14 posts tagged with "harvester"

Harvester's embedded Rancher UI may display warnings about expiring KubeVirt certificates. You can safely ignore these warnings because automatic certificate rotation is handled by KubeVirt and is enabled by default.

KubeVirt Certificate Rotation Strategy​

KubeVirt provides a self-signed certificate mechanism that rotates both CA and certifcates on a defined recurring interval. You can check the setting certificateRotateStrategy by running the following command:

kubectl get kubevirt -n harvester-system -o yaml

By default, the value of certificateRotateStrategy is empty, which means that KubeVirt uses its default rotation settings and no manual configuration is required.

certificateRotateStrategy: {}

Configuration Fields​

You can use the following fields to configure certificateRotateStrategy.

• .ca.duration: Validity period of the CA certificate. The default value is "168h".
• .ca.renewBefore: Amount of time before a CA certificate expires during which a new certificate is issued. The default value is "33.6h".
• .server.duration: Validity period of server component certificates (for example, virt-api, virt-handler, and virt-operator). The default value is "24h".
• .server.renewBefore: Amount of time before a server certificate expires during which a new certificate is issued. The default value is "4.8h".

Example of a complete configuration:

certificateRotateStrategy:
  selfSigned:
    ca:
      duration: 168h
      renewBefore: 33.6h
    server:
      duration: 24h
      renewBefore: 4.8h

Certificate Rotation Triggers​

Certificate rotation can be triggered by several conditions. The following list only outlines key triggers and is not exhaustive.

• Missing certificate: A required certificate does not exist.
• Invalid CA signature: A certificate was not signed by the specified CA.
• Proactive renewal: The renewBefore value takes effect. A new certificate must be issued before the current one expires.
• CA expiration: The CA certificate has expired, so the certificate signed by the CA is also rotated.

When certificate rotation is triggered, you should see virt-operator log records similar to the following:

{"component":"virt-operator","level":"info","msg":"secret kubevirt-virt-api-certs updated","pos":"core.go:278","timestamp":"2024-12-06T08:02:01.045809Z"}
{"component":"virt-operator","level":"info","msg":"secret kubevirt-controller-certs updated","pos":"core.go:278","timestamp":"2024-12-06T08:02:01.056759Z"}
{"component":"virt-operator","level":"info","msg":"secret kubevirt-exportproxy-certs updated","pos":"core.go:278","timestamp":"2024-12-06T08:02:01.063530Z"}
{"component":"virt-operator","level":"info","msg":"secret kubevirt-virt-handler-server-certs updated","pos":"core.go:278","timestamp":"2024-12-06T08:02:01.068608Z"}
{"component":"virt-operator","level":"info","msg":"secret kubevirt-virt-handler-certs updated","pos":"core.go:278","timestamp":"2024-12-06T08:02:01.074555Z"}
{"component":"virt-operator","level":"info","msg":"secret kubevirt-operator-certs updated","pos":"core.go:278","timestamp":"2024-12-06T08:02:01.078719Z"}
{"component":"virt-operator","level":"info","msg":"secret kubevirt-export-ca updated","pos":"core.go:278","timestamp":"2024-12-06T08:03:36.063496Z"}
{"component":"virt-operator","level":"info","msg":"secret kubevirt-ca updated","pos":"core.go:278","timestamp":"2024-12-06T08:04:06.052750Z"}

References​

• Harvester: Issue 5798
• https://kubevirt.io/2020/KubeVirt-Security-Fundamentals.html
• https://github.com/kubevirt/kubevirt/blob/v1.1.1/pkg/virt-operator/resource/generate/components/secrets.go#L326
• https://github.com/kubevirt/kubevirt/blob/v1.1.1/pkg/virt-operator/resource/apply/certificates.go

Scenarios:

1. The Harvester cluster is installed with 3+ nodes.

2. The Rancher Manager/Server is deployed independently. (Hereafter it is mentioned as Rancher Manager)

3. The Harvester cluster is imported to this Rancher Manager and works as a node driver.

4. The Rancher Manager deploys a couple of downstream K8s clusters, the machines/nodes of those clusters are backed by Harvester VMs.

5. There are also some traditional VMs deployed on the Harvester cluster, which have no direct connection with the Rancher Manager.

You plan to move those Harvester nodes geographically, or to power off the whole cluster for some time, it is essential to shutdown the Harvester cluster and restart later.

General Principle​

To safely shutdown a Harvester cluster, you need to follow the roughly reverse order of the cluster installation and the workload deployments.

Those facts need to be taken into account particularly:

1. The common methodology of Kubernetes operator/controller is to try things continuously until they meet expectations. When the cluster is shutting down node by node, if you don't stop those workloads in advance, they will try hard until the last node is off. It causes the last few nodes to have heavy CPU/memory/network/storage usage and increases the chance of data corruption.

2. Each Harvester node has limited capacity of CPU/memory/network/storage and the max-pod-number, when all workloads are crowded on the last few nodes, the unexpected pod eviction, scheduling failure and other phenomena may happen.

3. Harvester has embedded Longhorn as the default CSI driver, each PV can have 3 or more replicas, when replicas are rescheduled to other nodes, Longhorn will copy data from source node and rebuild the replica. Undoubtedly, stop the PVs as much as possible before the cluster shutdown to avoid the data moving.

4. Unlike normal Kubernetes deployments which have no PVs and are more flexible & agile to deploy anywhere on the cluster, the VMs are backed by massive sized PVs, slowly to move/migrate or even pinned on certain nodes to take the advantage of PCI-passthrough/vGPU/... and are much more sensitive to data consistency.

Needless to say, it is a bad practice to brutally power off the nodes on production environments.

1. Precondition​

1.1 Generate a Support-bundle File​

For trouble-shooting purpose, it is essential to follow this instruction to generate a support-bundle file before taking any actions. And make sure the workload namespaces are added.

1.2 Keep Network Stability​

A good practice is to have detailed documents about the infrastructure related settings.

• The bare metal server NIC slot/port connections with the remote (ToR) Switches.

• The VLAN for the management network.

• (Optional) The DHCP Server, ip-pools and ip-mac bindings for the Harvester cluster if DHCP server is used. If there is no fixed IP binding, when the server restarts after some days it may get a different IP from the DHCP server.

• The VLANs for the VM networks, the CIDRs, default gateways and optional DHCP servers.

• NTP servers.

• DNS servers.

• (Optional) The http proxy.

• (Optional) The private containerd-registry.

• (Optional) The firewall configurations.

See the Harvester ISO Installation to review the infrastructure related settings for the Harvester cluster.

Before the Harvester cluster is restarted later, check and test those settings again to make sure the infrastructure is ready.

2. Backup​

(Optional) Backup VMs if Possible​

It is always a good practice to backup things before a whole cluster shutdown.

(Optional) Backup Downstream K8s Clusters if Possible​

Harvester doesn't touch the (Rancher Manager managed) downstream K8s clusters' workload, when they are not able to be migrated to other node drivers, suggests to backup those clusters.

(Optional) Stop or Migrate Downstream K8s Clusters if Possible​

Harvester doesn't touch the downstream K8s clusters' workload, but suggests to stop or migrate the downstream clusters to avoid your service interruption.

3. Shutdown Workloads​

3.1 Shutdown Traditional VMs​

1. Shutdown VM from the VM shell (e.g. Linux shutdown command), the OS itself will save data to disks.

2. Check the VM status from Harvester UI - VM page, when it is not Off, then click the Stop command.

3.2 Shutdown Rancher Downstream Cluster Machines(VMs)​

Suppose your Harvester cluster was imported to Rancher as a node driver before.

When Rancher deploys a downstream cluster on node driver Harvester, it creates a couple of VMs on Harvester automatically. Directly stopping those VMs on Harvester is not a good practice when Rancher is still managing the downstream cluster. For example, Rancher may create new VMs if you stop them from Harvester.

If you have got a solution to shutdown those downstream clusters, and check those VMs are Off; or there is no downstream clusters, then jump to the step disable some addons.

Unless you have already deleted all the downstream clusters which are deploy on this Harvester, DO NOT remove this imported Harvester from the Rancher Manager. Harvester will get a different driver-id when it is imported later, but those aforementioned downstream clusters are connected to driver-id.

To safely shutdown those VMs but still keep the Rancher Manager managed downstream cluster alive, please follow the steps below:

Disconnect Harvester from the Rancher Manager​

The cattle-cluster-agent-*** pod is the direct connection between Rancher Manager and Harvester cluster, and this pod is monitored and managed by the embedded Rancher in Harvester, scaling down this pod does not work. The embedded Rancher will scale it up automatically.

Run steps below to suspend the connection.

All following CLI commands are executed upon Harvester cluster.

1. Set the management.cattle.io/scale-available of deployment rancher to be "" instead of "3" or other values.

This change will stop the auto-scaling.

harvester$ kubectl edit deployment -n cattle-system rancher
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
...
    management.cattle.io/scale-available: "3"  // record this value, and change it to ""
...
  generation: 16
  labels:
    app: rancher
    app.kubernetes.io/managed-by: Helm
...
  name: rancher
  namespace: cattle-system

2. Scale down the rancher deployment.

harvester$ kubectl scale deployment -n cattle-system rancher --replicas=0
deployment.apps/rancher scaled


harvester$ get deployment -n cattle-system rancher
NAME      READY   UP-TO-DATE   AVAILABLE   AGE
rancher   0/0     0            0           33d

3. Make sure the rancher-* pods are gone.

Check the rancher-* pods on cattle-system are gone, if any of them is stucking at Terminating, use kubectl delete pod -n cattle-system rancher-pod-name --force to delete it.

harvester$ kubectl get pods -n cattle-system
NAME                                         READY   STATUS        RESTARTS       AGE
..
rancher-856f674f7d-5dqb6                     0/1     Terminating   0              3d22h
rancher-856f674f7d-h4vsw                     1/1     Running       23 (68m ago)   33d
rancher-856f674f7d-m6s4r                     0/1     Pending       0              3d19h
...

4. Scale down the cattle-cluster-agent deployment.

harvester$ kubectl scale deployment -n cattle-system cattle-cluster-agent --replicas=0
deployment.apps/cattle-cluster-agent scaled


harvester$ kubectl get deployment -n cattle-system
NAME                        READY   UP-TO-DATE   AVAILABLE   AGE
cattle-cluster-agent        0/0     0            0           23d

Please note:

1. From now on, this Harvester is Unavailable on the Rancher Manager.

2. The Harvester WebUI returns 503 Service Temporarily Unavailable, all operations below can be done via kubectl.

Shutdown Rancher Downstream Cluster Machines(VMs)​

1. Shutdown VM from the VM shell (e.g. Linux shutdown command).

2. Check the vmi instances, if any is still Running, stop it.

harvester$ kubectl get vmi
NAMESPACE   NAME   AGE    PHASE     IP            NODENAME   READY
default     vm1    5m6s   Running   10.52.0.214   harv41     True


harvester$ virtctl stop vm1 --namespace default
VM vm1 was scheduled to stop

harvester$ kubectl get vmi -A
NAMESPACE   NAME   AGE    PHASE     IP            NODENAME   READY
default     vm1    5m6s   Running   10.52.0.214   harv41     False


harvester$ kubectl get vmi -A
No resources found

harvester$ kubectl get vm -A
NAMESPACE   NAME   AGE   STATUS    READY
default     vm1    7d    Stopped   False

3.3 Disable Some Addons​

Harvester has some addons which are backed by PVCs, it is necessary to disable them.

The rancher-monitoring addon should be disabled.

The experimental Rancher Manager addon should be disabled.

For other addons, please follow the Harvester document to keep or disable them.

From Harvester UI addon page, write down those none-Disabled addons, click Disable menu to disable them, wait until the state becomes Disabled

From CLI:

$ kubectl get addons.harvesterhci.io -A

NAMESPACE                  NAME                    HELMREPO                                                 CHARTNAME                         ENABLED
cattle-logging-system      rancher-logging         http://harvester-cluster-repo.cattle-system.svc/charts   rancher-logging                   false
cattle-monitoring-system   rancher-monitoring      http://harvester-cluster-repo.cattle-system.svc/charts   rancher-monitoring                true
harvester-system           harvester-seeder        http://harvester-cluster-repo.cattle-system.svc/charts   harvester-seeder                  false
harvester-system           nvidia-driver-toolkit   http://harvester-cluster-repo.cattle-system.svc/charts   nvidia-driver-runtime             false
harvester-system           pcidevices-controller   http://harvester-cluster-repo.cattle-system.svc/charts   harvester-pcidevices-controller   false
harvester-system           vm-import-controller    http://harvester-cluster-repo.cattle-system.svc/charts   harvester-vm-import-controller    false

Example: disable rancher-monitoring

$ kubectl edit addons.harvesterhci.io -n cattle-monitoring-system rancher-monitoring

...
spec:
  chart: rancher-monitoring
  enabled: false               // set this field to be false
...

3.4 (Optional) Disable other Workloads​

If you have deployed some customized workloads on the Harvester cluster directly, it is better to disable/remove them.

3.5 Check Longhorn Volumes​

The volumes should be in state detached, check the related workload if some volumes are still in state attached.

harvester$ kubectl get volume -A
NAMESPACE         NAME                                       DATA ENGINE   STATE      ROBUSTNESS   SCHEDULED   SIZE          NODE     AGE
longhorn-system   pvc-3323944c-00d9-4b35-ae38-a00b1e8a8841   v1            detached   unknown                  5368709120             13d
longhorn-system   pvc-394713a4-d08c-4a45-bf7a-d44343f29dea   v1            attached   healthy                  6442450944    harv41   8d    // still attached and in use
longhorn-system   pvc-5cf00ae2-e85e-413e-a4f1-8bc4242d4584   v1            detached   unknown                  2147483648             13d
longhorn-system   pvc-620358ca-94b3-4bd4-b008-5c144fd815c9   v1            attached   healthy                  2147483648    harv41   8d    // still attached and in use
longhorn-system   pvc-8174f05c-919b-4a8b-b1ad-4fc110c5e2bf   v1            detached   unknown                  10737418240            13d

4. Shutdown Nodes​

Get all nodes from Harvester WebUI Host Management.

From CLI:

harvester$ kubectl get nodes -A
NAME     STATUS   ROLES                       AGE   VERSION
harv2    Ready    <none>                      24d   v1.27.10+rke2r1  // worker node
harv41   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1  // control-plane node
harv42   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1  // control-plane node
harv43   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1  // control-plane node

4.1 Shutdown the Worker Nodes​

1. SSH to the Harvester worker nodes.

2. Run command sudo -i shutdown.

$ sudo -i shutdown

Shutdown scheduled for Mon 2024-07-22 06:58:56 UTC, use 'shutdown -c' to cancel.

3. Wait until all those nodes are down.

4.2 Shutdown Control-plane Nodes and Witness Node​

So far, there are generally three control-plane nodes left, and three etcd-* pods are running in kube-system namespaces.

The first step is to find which one of the etcd-* pod is running as the leader.

Run below command upon any of the etcd-* pod, note the IS LEADER column.

$ kubectl exec -n kube-system etcd-harv41 -- env ETCDCTL_API=3 etcdctl endpoint status --cluster -w table --cacert /var/lib/rancher/rke2/server/tls/etcd/server-ca.crt --cert /var/lib/rancher/rke2/server/tls/etcd/server-client.crt --key /var/lib/rancher/rke2/server/tls/etcd/server-client.key

+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
|           ENDPOINT           |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| https://192.168.122.141:2379 | c70780b7862269c9 |   3.5.9 |   34 MB |      true |      false |        45 |    6538756 |            6538756 |        |
| https://192.168.122.142:2379 | db04095b49eb5352 |   3.5.9 |   34 MB |     false |       true |        45 |    6538756 |            6538756 |        |
| https://192.168.122.143:2379 | c27585769b2ce977 |   3.5.9 |   34 MB |     false |       true |        45 |    6538756 |            6538756 |        |
+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

Witness Node​

If your cluster has one Witness Node and the etcd leader happens to be on this node.

harvester$ kubectl get nodes -A
NAME     STATUS     ROLES                       AGE    VERSION
harv2    Ready      <none>                      25d    v1.27.10+rke2r1  // worker node
harv41   Ready      control-plane,etcd,master   55d    v1.27.10+rke2r1  // control-plane node
harv42   Ready      control-plane,etcd,master   55d    v1.27.10+rke2r1  // control-plane node
harv43   Ready      etcd                         1d    v1.27.10+rke2r1  // witness node

+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
|           ENDPOINT           |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| https://192.168.122.141:2379 | c70780b7862269c9 |   3.5.9 |   34 MB |     false |       true |        46 |    6538829 |            6538829 |        |
| https://192.168.122.142:2379 | db04095b49eb5352 |   3.5.9 |   34 MB |     false |       true |        46 |    6538829 |            6538829 |        |
| https://192.168.122.143:2379 | a21534d02463b347 |   3.5.9 |   34 MB |      true |      false |        46 |    6538829 |            6538829 |        |
+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

Run kubectl delete pod -n kube-system etcd-name command to delete the etcd pod on the witness node to trigger the pod replacement and leader re-election so that the etcd leader will be located on one of the control-plane nodes. Check the etcd leader again to make sure.

+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
|           ENDPOINT           |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| https://192.168.122.141:2379 | c70780b7862269c9 |   3.5.9 |   34 MB |      true |      false |        47 |    6538833 |            6538833 |        |
| https://192.168.122.142:2379 | db04095b49eb5352 |   3.5.9 |   34 MB |     false |       true |        47 |    6538833 |            6538833 |        |
| https://192.168.122.143:2379 | a21534d02463b347 |   3.5.9 |   34 MB |     false |       true |        47 |    6538833 |            6538833 |        |
+------------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

To now, the etcd has three running instances and the leader is located on the control-plane node.

Shutdown the two IS LEADER == false nodes one by one.

harvester-node-shell$ sudo -i shutdown

4.3 Shutdown the Last Control-plane Node​

Shutdown the last IS LEADER == true node. Remember its physical information for restarting it first in the steps below.

harvester-last-node-shell$ sudo -i shutdown

5. Restart​

If the Harvester cluster has been moved to a new location, or has been off for days, or your infrastructure has changes, check and test the network stability.

5.1 Restart the Control-plane Nodes and the Witness Node​

The first step is to start those etcd located nodes one after another.

Restart the Leader Control-plane Node​

Power on the last shutdown node first. After about three minutes, continue the next step.

When you check the etcd pod log on this node, the following message may be observed.

sent MsgPreVote request to db04095b49eb5352 at term 5

"msg":"prober detected unhealthy status","round-tripper-name":"ROUND_TRIPPER_RAFT_MESSAGE","remote-peer-id":"db04095b49eb5352","rtt":"0s","error":"dial tcp 192.168.122.142:2380: connect: no route to host"

The etcd is wating for the other two members to be online and then vote a leader.

Restart the Rest of Control-plane Nodes and the Witness Node​

Power on the rest nodes which also hosted the etcd pod before.

Wait until all the three control-plane nodes or possibly two control-plane and one witness nodes are Ready.

From CLI:

harvester$ kubectl get nodes -A
NAME     STATUS   ROLES                       AGE   VERSION
harv41   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1
harv42   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1
harv43   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1

The etcd forms a quorum and can tolerant the failure of one node.

Check the VIP​

The following EXTERNAL-IP should be the same as the VIP of the Harvester cluster.

harvester$ kubectl get service -n kube-system ingress-expose
NAME             TYPE           CLUSTER-IP     EXTERNAL-IP       PORT(S)                      AGE
ingress-expose   LoadBalancer   10.53.50.107   192.168.122.144   443:32701/TCP,80:31480/TCP   34d

5.2 Restart the Worker Nodes​

Wait until all nodes are Ready.

From CLI:

harvester$ kubectl get nodes -A
NAME     STATUS   ROLES                       AGE   VERSION
harv2    Ready    <none>                      24d   v1.27.10+rke2r1  // worker node
harv41   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1
harv42   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1
harv43   Ready    control-plane,etcd,master   54d   v1.27.10+rke2r1

Healthy Check​

Basic Components​

Harvester deploys some basic components on the following namespaces. When a bare-metal server is powered on, it may take upto around 15 minutes for the Harvester OS to be running and all the deployments on this node to be ready.

If any of them continues to show the status like Failed/CrashLoopBackOff, a troubleshooting is needed to confirm the root cause.

NAMESPACE                         NAME                                                     READY   STATUS      RESTARTS       AGE
cattle-fleet-local-system         fleet-agent-645766877f-bt424                             1/1     Running     0              11m

cattle-fleet-system               fleet-controller-57f78dcd48-5tkkj                        1/1     Running     4 (14m ago)    42h
cattle-fleet-system               gitjob-d5bb7b548-jscgk                                   1/1     Running     2 (14m ago)    42h

cattle-system                     harvester-cluster-repo-6c6458bd46-7jcrl                  1/1     Running     2 (14m ago)    42h
cattle-system                     system-upgrade-controller-6f86d6d4df-f8jg7               1/1     Running     2 (14m ago)    42h
cattle-system                     rancher-7bc9d94b87-g4k4v                                 1/1     Running     3 (14m ago)    42h  // note: if embedded Rancher was stopped in the above steps, it is not Running now
cattle-system                     rancher-webhook-6c5c6fbb65-2cbbs                         1/1     Running     2 (14m ago)    42h

harvester-system                  harvester-787b467f4-qlfwt                                1/1     Running     2 (14m ago)    39h
harvester-system                  harvester-load-balancer-56d9c8758c-cvcmk                 1/1     Running     2 (14m ago)    42h
harvester-system                  harvester-load-balancer-webhook-6b4d4d9d6b-4tsgl         1/1     Running     2 (14m ago)    42h
harvester-system                  harvester-network-controller-9pzxh                       1/1     Running     2 (14m ago)    42h
harvester-system                  harvester-network-controller-manager-69bcf67c7f-44zqj    1/1     Running     2 (14m ago)    42h
harvester-system                  harvester-network-webhook-6c5d48bdf5-8kn9r               1/1     Running     2 (14m ago)    42h
harvester-system                  harvester-node-disk-manager-c4c5k                        1/1     Running     3 (14m ago)    42h
harvester-system                  harvester-node-manager-qbvbr                             1/1     Running     2 (14m ago)    42h
harvester-system                  harvester-node-manager-webhook-6d8b48f559-m5shk          1/1     Running     2 (14m ago)    42h
harvester-system                  harvester-webhook-87dc4cdd8-jg2q6                        1/1     Running     2 (14m ago)    39h
harvester-system                  kube-vip-n4s8l                                           1/1     Running     3 (14m ago)    42h
harvester-system                  virt-api-799b99fb65-g8wgq                                1/1     Running     2 (14m ago)    42h
harvester-system                  virt-controller-86b84c8f8f-4hhlg                         1/1     Running     2 (14m ago)    42h
harvester-system                  virt-controller-86b84c8f8f-krq4f                         1/1     Running     3 (14m ago)    42h
harvester-system                  virt-handler-j9gwn                                       1/1     Running     2 (14m ago)    42h
harvester-system                  virt-operator-7585847fbc-hvs26                           1/1     Running     2 (14m ago)    42h

kube-system                       cloud-controller-manager-harv41                          1/1     Running     5 (14m ago)    42h
kube-system                       etcd-harv41                                              1/1     Running     2              42h
kube-system                       harvester-snapshot-validation-webhook-8594c5f8f8-8mk57   1/1     Running     2 (14m ago)    42h
kube-system                       harvester-snapshot-validation-webhook-8594c5f8f8-dkjmf   1/1     Running     2 (14m ago)    42h
kube-system                       harvester-whereabouts-cpqvl                              1/1     Running     2 (14m ago)    42h

kube-system                       kube-apiserver-harv41                                    1/1     Running     2              42h
kube-system                       kube-controller-manager-harv41                           1/1     Running     4 (14m ago)    42h
kube-system                       kube-proxy-harv41                                        1/1     Running     2 (14m ago)    42h
kube-system                       kube-scheduler-harv41                                    1/1     Running     2 (14m ago)    42h
kube-system                       rke2-canal-d5kmc                                         2/2     Running     4 (14m ago)    42h
kube-system                       rke2-coredns-rke2-coredns-84b9cb946c-qbwnb               1/1     Running     2 (14m ago)    42h
kube-system                       rke2-coredns-rke2-coredns-autoscaler-b49765765-6bjsk     1/1     Running     2 (14m ago)    42h
kube-system                       rke2-ingress-nginx-controller-cphgw                      1/1     Running     2 (14m ago)    42h
kube-system                       rke2-metrics-server-655477f655-gsnsc                     1/1     Running     2 (14m ago)    42h
kube-system                       rke2-multus-8nqg4                                        1/1     Running     2 (14m ago)    42h
kube-system                       snapshot-controller-5fb6d65787-nmjdh                     1/1     Running     2 (14m ago)    42h
kube-system                       snapshot-controller-5fb6d65787-phvq7                     1/1     Running     3 (14m ago)    42h

longhorn-system                   backing-image-manager-5c32-ea70                          1/1     Running     0              13m
longhorn-system                   csi-attacher-749459cf65-2x792                            1/1     Running     6 (13m ago)    42h
longhorn-system                   csi-attacher-749459cf65-98tj4                            1/1     Running     5 (13m ago)    42h
longhorn-system                   csi-attacher-749459cf65-nwglq                            1/1     Running     5 (13m ago)    42h
longhorn-system                   csi-provisioner-775b4f76f4-h9mwd                         1/1     Running     5 (13m ago)    42h
longhorn-system                   csi-provisioner-775b4f76f4-nvjzt                         1/1     Running     5 (13m ago)    42h
longhorn-system                   csi-provisioner-775b4f76f4-zvd6w                         1/1     Running     5 (13m ago)    42h
longhorn-system                   csi-resizer-68867d54f5-4hf5j                             1/1     Running     5 (13m ago)    42h
longhorn-system                   csi-resizer-68867d54f5-fs9ht                             1/1     Running     5 (13m ago)    42h
longhorn-system                   csi-resizer-68867d54f5-ht5hj                             1/1     Running     6 (13m ago)    42h
longhorn-system                   csi-snapshotter-8469656cc7-6c47f                         1/1     Running     6 (13m ago)    42h
longhorn-system                   csi-snapshotter-8469656cc7-9kk2v                         1/1     Running     5 (13m ago)    42h
longhorn-system                   csi-snapshotter-8469656cc7-vf9z4                         1/1     Running     5 (13m ago)    42h
longhorn-system                   engine-image-ei-94d5ee6c-pqx9h                           1/1     Running     2 (14m ago)    42h
longhorn-system                   instance-manager-beb75434e263a2aa9eedc0609862fed2        1/1     Running     0              13m
longhorn-system                   longhorn-csi-plugin-85qm7                                3/3     Running     14 (13m ago)   42h
longhorn-system                   longhorn-driver-deployer-6448498bc6-sv857                1/1     Running     2 (14m ago)    42h
longhorn-system                   longhorn-loop-device-cleaner-bqg9v                       1/1     Running     2 (14m ago)    42h
longhorn-system                   longhorn-manager-nhxbl                                   2/2     Running     6 (14m ago)    42h
longhorn-system                   longhorn-ui-7f56fcf5ff-clc8b                             1/1     Running     6 (13m ago)    42h
longhorn-system                   longhorn-ui-7f56fcf5ff-m95sh                             1/1     Running     7 (13m ago)    42h

Storage Network​

When the Storage Network has been enabled on the cluster, follow those steps to check if the Longhorn PODs have the correct second IP assigned to them.

5.3 Enable Addons​

Enable those previously disabled addons, wait until they are DepoloySuccessful.

5.4 Restore the Connection to the Rancher Manager​

Run following 1, 2 commands on the Harvester cluster.

1. Set the management.cattle.io/scale-available of rancher deployment to be the value recorded on the above steps.

This change will enable the auto-scaling.

harvester$ kubectl edit deployment -n cattle-system rancher
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
...
    management.cattle.io/scale-available: "3"  // recorded on the above steps
...
  generation: 16
  labels:
    app: rancher
    app.kubernetes.io/managed-by: Helm
...
  name: rancher
  namespace: cattle-system

2. Scale up the rancher deployment on Harvester cluster.

harvester$ kubectl scale deployment -n cattle-system rancher --replicas=3
deployment.apps/rancher scaled

harvester$ get deployment -n cattle-system rancher
NAME      READY   UP-TO-DATE   AVAILABLE   AGE
rancher   0/0     0            0           33d

...

harvester$ kubectl get deployment -n cattle-system
NAME                        READY   UP-TO-DATE   AVAILABLE   AGE
cattle-cluster-agent        2/2     2            2           23d
rancher                     1/2     2            1           33d

3. Check the virtualization management on the Rancher Manager.

The Harvester cluster continues to be active on the Rancher Virtualization Management .

4. Check the Harvester cluster WebUI.

You should be able to access the Harvester WebUI again.

5.5 Start VMs​

5.1 Start Traditional VMs​

When there are many VMs deployed on the cluster, don't start all the VMs at the same time, suggest starting them group by group.

Wait until they are Running.

5.2 Rancher Downstream Cluster Machines(VMs)​

After the Harvester cluster is re-connected to the Rancher Manager successfully, the Rancher Manager will handle the downstream K8s clusters' machines(vms) automatically. Wait until all the downstream clusters are ready.

See Rancher Manager Access Downstream Clusters to monitor and operator the downstream clusters.

If Rancher Manager does not restart the machines(vms) automatically, you can start those VMs from the Vitrual Machines page on Harvester UI.

5.6 Generate a new Support-bundle File​

Generate a new support-bundle file on the Harvester cluster.

Together with the previously generated support-bundle file, the two files record the cluster settings, configurations and status before shutting down and after rebooting. It is helpful for troubleshooting.

User-Provided Credentials on Harvester​

When installing a Harvester cluster, you are asked to provide the following credential related information:

• Cluster token of the first node that is added to the cluster. Other nodes must use this token to join the cluster.

• Password for the default Linux user rancher on each node.

• SSH keys on each node (optional).

• HTTP proxy on each node (optional).

You may plan to change them from time to time, the following paragraphs describe the detailed steps.

Cluster Token​

Cluster Token on Nodes Joining an Existing Cluster​

When a node is unable to join a cluster because of a cluster token error, perform the recommended troubleshooting steps.

Cluster Token (RKE2 Token Rotation)​

Harvester does not allow you to change the cluster token even if RKE2 is a core component of Harvester.

The RKE2 documentation states that the November 2023 releases of RKE2 (v1.28.3+rke2r2, v1.27.7+rke2r2, v1.26.10+rke2r2, and v1.25.15+rke2r2) allow you to rotate the cluster token using the command rke2 token rotate --token original --new-token new.

During testing, the command was run on the first node of a cluster running Harvester v1.3.0 with RKE2 v1.27.10+rke2r1.

1. Rotate the token on initial node.

/opt/rke2/bin $ ./rke2 token rotate --token rancher --new-token rancher1

WARNING: Recommended to keep a record of the old token. If restoring from a snapshot, you must use the token associated with that snapshot.
WARN[0000] Cluster CA certificate is not trusted by the host CA bundle, but the token does not include a CA hash. Use the full token from the server's node-token file to enable Cluster CA validation. 
Token rotated, restart rke2 nodes with new token

2. When the first cluster node was rebooted, RKE2 service was unable to start.

RKE2 log:

...
May 29 15:45:11 harv41 rke2[3293]: time="2024-05-29T15:45:11Z" level=info msg="etcd temporary data store connection OK"
May 29 15:45:11 harv41 rke2[3293]: time="2024-05-29T15:45:11Z" level=info msg="Reconciling bootstrap data between datastore and disk"
May 29 15:45:11 harv41 rke2[3293]: time="2024-05-29T15:45:11Z" level=fatal msg="Failed to reconcile with temporary etcd: bootstrap data already found and encrypted with different token"
May 29 15:45:11 harv41 systemd[1]: rke2-server.service: Main process exited, code=exited, status=1/FAILURE
...

This known issue was logged on Github issue rke2 token rotate does not work as expected (v1.27.10+rke2r1).

:::Warning

Do not attempt to rotate the RKE2 token on your cluster before Harvester announces official support for this feature (even if the embedded RKE2 binary has the token rotate option).

:::

Password of the Default User rancher​

This process is node-specific. You must change the password of the default user on each node even if the same password is used on all Harvester nodes.

SSH keys​

You must log into a Harvester node using the default user account rancher to change the SSH keys.

HTTP Proxy​

After a Harvester cluster is installed, you can use the Harvester UI to change the HTTP proxy.

Alternatively, you can use kubectl or the rest API against the URI /harvesterhci.io.setting/http-proxy.

$ kubectl get settings.harvesterhci.io http-proxy -oyaml

apiVersion: harvesterhci.io/v1beta1
default: '{}'
kind: Setting
metadata:
  creationTimestamp: "2024-05-13T20:44:20Z"
  generation: 1
  name: http-proxy
  resourceVersion: "5914"
  uid: 282506bb-f1dd-4247-bf0e-93640698c1f5
status: {}

Harvester has a webhook that checks this setting to ensure it meets all conditions, e.g. the internal IPs and CIDRs are specified in the noProxy field.

Other Credentials and Settings​

auto-rotate-rke2-certs​

Harvester is built on top of Kubernetes, RKE2, and Rancher. RKE2 generates a list of *.crt and *.key files that allow Kubernetes components to function. The *.crt file expires after one year by default.

$ ls /var/lib/rancher/rke2/server/tls/ -alth

...
-rw-r--r-- 1 root root  570 May 27 08:45 server-ca.nochain.crt
-rw------- 1 root root 1.7K May 27 08:45 service.current.key
-rw-r--r-- 1 root root  574 May 27 08:45 client-ca.nochain.crt
drwxr-xr-x 2 root root 4.0K May 13 20:45 kube-controller-manager
drwxr-xr-x 2 root root 4.0K May 13 20:45 kube-scheduler
drwx------ 6 root root 4.0K May 13 20:45 .
drwx------ 8 root root 4.0K May 13 20:45 ..
-rw-r--r-- 1 root root 3.9K May 13 20:40 dynamic-cert.json
drwx------ 2 root root 4.0K May 13 20:39 temporary-certs
-rw------- 1 root root 1.7K May 13 20:39 service.key
-rw-r--r-- 1 root root 1.2K May 13 20:39 client-auth-proxy.crt
-rw------- 1 root root  227 May 13 20:39 client-auth-proxy.key
-rw-r--r-- 1 root root 1.2K May 13 20:39 client-rke2-cloud-controller.crt
...
-rw-r--r-- 1 root root 1.2K May 13 20:39 client-admin.crt
-rw------- 1 root root  227 May 13 20:39 client-admin.key
...


$ openssl x509 -enddate -noout -in /var/lib/rancher/rke2/server/tls/client-admin.crt

notAfter=May 13 20:39:42 2025 GMT

When a cluster has been running for over one year, Kubernetes components may fail to start after upgrades or node rebooting. The workaround is to delete the related files and restart the pod.

Harvester v1.3.0 added the setting auto-rotate-rke2-certs, which allows you to set the Harvester cluster to automatically rotate certificates for RKE2 services. When you enable the setting and specify a certificate validity period, Harvester automatically replaces the certificate before the specified period ends.

Harvester Cloud Credentials​

See the article Renew Harvester Cloud Credentials.

additional-ca​

See the documentation for this setting.

ssl-certificates​

See the documentation for this setting.

ssl-parameters​

See the documentation for this setting.

containerd-registry​

See the documentation for this setting.

Expiration of kubeconfig Tokens in Rancher 2.8.x​

In Rancher 2.8.x, the default value of the kubeconfig-default-token-ttl-minutes setting is 30 days.

A side effect of using this default value is the expiration of authentication tokens embedded in kubeconfigs that Rancher uses to provision guest Kubernetes clusters on Harvester. When such tokens expire, Rancher loses the ability to perform management operations for the corresponding Rancher-managed guest Kubernetes clusters. Issue #44912 tracks the issue described in this article.

Workaround​

You can patch the expired Harvester cloud credentials to use a new authentication token.

1. Identify the expired cloud credentials and which Harvester cluster is affected by them.

   

2. Download a new kubeconfig file for the affected Harvester cluster.

   

3. Patch the cloud credentials. The cloud credential is stored as a secret in cattle-global-data namespace, and can be replaced with the new kubeconfig file. Ensure that the environment variable KUBECONFIG_FILE contains the path to the new kubeconfig file.

   #!/bin/sh
   CLOUD_CREDENTIAL_ID=$1  # .metadata.name of the cloud credential
   KUBECONFIG_FILE=$2      # path to the downloaded kubeconfig file
   
   kubeconfig="$(base64 -w 0 "${KUBECONFIG_FILE}")"
   
   patch_file=$(mktemp)
   
   cat > ${patch_file} <<EOF
   data:
     harvestercredentialConfig-kubeconfigContent: $kubeconfig
   EOF
   
   kubectl patch secret ${CLOUD_CREDENTIAL_ID} -n cattle-global-data --patch-file ${patch_file} --type merge
   rm ${patch_file}
   

   Copy

   important

   macOS users must use gbase64 to ensure that the -w flag is supported.

Expiration of kubeconfig Tokens in Rancher 2.9.3​

In Rancher 2.9.3 and later versions, the Rancher UI displays a warning when a Harvester cloud credential or a related cluster contains an expired token. You can renew the token on the Cloud Credentials screen by selecting ⋮ > Renew, or the Clusters screen by selecting ⋮ > Renew Cloud Credential

Through v1.3.0, no explicit support has been provided for using Harvester (installing, booting, and running) with any type of storage that is not locally attached. This is in keeping with the philosophy of Hyper-Converged Infrastructure (HCI), which by definition hosts computational capability, storage, and networking in a single device or a set of similar devices operating in a cluster.

However, there are certain limited conditions that allow Harvester to be used on nodes without locally-attached bootable storage devices. Specifically, the use of converged network adapters (CNAs) as well as manual changes to the boot loader configuration of the installed system are required.

Concepts, Requirements, and Limitations​

This section describes background concepts and outlines requirements and limitations that you must consider before performing the procedure. For more information about the described concepts, see the references listed at the end of this article.

iSCSI Concepts and Terminology​

SCSI (Small Computer System Interface) is a set of standards for transferring data between computers systems and I/O devices. It is primarily used with storage devices.

The SCSI standards specify the following:

• SCSI protocol: A set of message formats and rules of exchange
• SCSI transports: Methods for physically connecting storage devices to the computer system and transferring SCSI messages between them

A number of SCSI transports are defined, including the following:

• SAS (Serial Attached SCSI) and UAS (USB Attached SCSI): Used to access SCSI storage devices that are directly attached to the computers using that storage
• FCP (Fibre Channel Protocol) and iSCSI (Internet SCSI): Permit computer systems to access storage via a Storage Area Network (SAN), where the storage devices are attached to a system other than the computers using that storage

The SCSI protocol is a client-server protocol, which means that all interaction occurs between clients that send requests and a server that services the requests. In the SCSI context, the client is called the initiator and the server is called the target. iSCSI initiators and targets identify themselves using a specially formatted identifier called an iSCSI qualified name (IQN). The controller used to provide access to the storage devices is commonly called a host bus adapter (HBA).

When using iSCSI, access is provided by a traditional Internet protocol, with an extra layer to encapsulate SCSI commands within TCP/IP messages. This can be implemented entirely in software (transferring messages using a traditional NIC), or it can be "offloaded" to a "smart" NIC that contains the iSCSI protocol and provides access through special firmware. Such NICs, which provide both a traditional Ethernet interface for regular Internet traffic and a higher-level storage interface for iSCSI services, are often called converged network adapters (CNAs).

Systems with iSCSI CNAs can be configured to enable the system bootstrap firmware to boot the system via iSCSI. In addition, if the loaded operating system is aware of such an interface provided by the CNA, it can access the bootstrap device using that firmware interface as if it were a locally attached device without requiring initialization of the operating system's full software iSCSI protocol machinery.

Additional Concepts and Terminology​

Harvester must be installed on a bootable storage device, which is referred to as the boot disk.

Other storage devices, which are referred to as non-boot disks, may also be used in the Harvester ecosystem.

Requirements​

You must install Harvester on a node with a converged NIC that provides iSCSI offload capability with firmware support. This firmware must specifically support the iSCSI Boot Firmware Table (iBFT).

Limitations​

The procedure will not work in environments with the following conditions:

• iSCSI is not implemented in a converged NIC.
• Nodes boot via PXE.
• Harvester is installed only on virtual machines.

Procedure​

The following is a summary of the procedure. Individual steps, which are described in the following sections, must be performed interactively. A fully automated installation is not possible at this time.

1. Provision storage for your Harvester node on your iSCSI server system.
2. Configure system firmware to boot via iSCSI using the available CNA.
3. Boot the Harvester install image and install to the iSCSI device.
4. On first Harvester boot after installation, edit the kernel boot parameters in the GRUB kernel command line.
5. Permanently edit the GRUB configuration file in the normally read-only partition.

1. Provision storage for your Harvester node on your iSCSI server system.​

Before attempting to install Harvester onto a disk accessed by iSCSI, the storage must first be provisioned on the storage server.

The details depend on the storage server and will not be discussed here.

However, several pieces of information must be obtained in order for the system being installed to be able to access the storage using iSCSI.

• The IP address and port number of the iSCSI server.
• The iSCSI Qualified Name (IQN) of the iSCSI target on the server.
• The LUN of the volume on the server to be accessed from the client as the disk on which Harvester will be installed.
• Depending on on how the server is administered, authentication parameters may also be required.

These items of information will be determined by the server system.

In addition, an IQN must be chosen for the client system to be used as its initiator identifier.

An IQN is a string in a certain format. In general, any string in the defined format can be used as long as it is unique. However, specific environments may place stricter requirements on the choice of names.

The format of an IQN is illustrated in the following example:

    iqn.2024-02.com.example:cluster1-node0-boot-disk

There are lots of variations of this format, and this is just an example.

The correct name to use should be chosen in consultation with the administrator of your storage server and storage area network.

2. Configure system firmware to boot via iSCSI using the available CNA.​

When your system to be installed powers on or is reset, you must enter the firmware setup menu to change the boot settings and enable booting via iSCSI.

Precise details for this are difficult to provide because they vary from system to system.

It is typical to force the system to enter the firmware settings menu by typing a special key such as F2, F7, ESC, etc. Which one works for your system varies. Often the system will display a list of which key(s) are available for specific firmware functions, but it is not uncommon for the firmware to erase this list and start to boot after only a very short delay, so you have to pay close attention.

If in doubt, consult the system provider's documentation. An example document link is provided in the References section. Other vendors should provide similar documentation.

The typical things you need to configure are:

• Enable UEFI boot
• Configure iSCSI initiator and target parameters
• Enable the iSCSI device in the boot menu
• Set the boot order so that your system will boot from the iSCSI device

Boot the Harvester install image and install to the iSCSI device​

This can be done by whatever means you would normally use to load the Harvester install image.

The Harvester installer should automatically "see" the iSCSI device in the dialog where you chose the installation destination. Choose this device to install.

Installation should proceed and complete normally.

When installation completes, your system should reboot.

4. On first boot, edit kernel boot parameters in the GRUB kernel command line.​

As your system starts to come up after the first reboot, the firmware will load the boot loader (GRUB) from the iSCSI device, and GRUB will be able to use this device to load the kernel.

However, the kernel will not be aware of the iSCSI boot disk unless you modify the kernel parameters in the GRUB command line.

If you don't modify the kernel parameters, then system startup procedures will fail to find the COS_OEM and other paritions on the boot disk, and it will be unable to access the cloud-init configuration or any of the container images needed to

The first time the GRUB menu appears after installation, you should stop the GRUB boot loader from automatically loading the kernel, and edit the kernel command line.

To stop GRUB from automatically loading the kernel, hit the ESC key as soon as the menu appears. You will only have a few seconds to do this before the system automatically boots.

Then, type "e" to edit the GRUB configuration for the first boot option.

It will show you something similar to the following:

setparams 'Harvester v1.3.0'

  # label is kept around for backward compatibility
  set label=${active_label}
  set img=/cOS/active.img
  loopback $loopdev /$img
  source $(loopdev)/etc/cos/bootargs.cfg
  linux ($loopdev)$kernel $kernelcmd ${extra_cmdline} ${extra_active_cmdline}
  initrd ($loopdev)$initramfs

Move the cursor down to the line that begins with linux, and move the cursor to the end of that line.

Append the following string (two parameters): rd.iscsi.firmware rd.iscsi.ibft.

The line beginning with linux should now look like this:

  linux ($loopdev)$kernel $kernelcmd ${extra_cmdline} ${extra_active_cmdline} rd.iscsi.firmware rd.iscsi.ibft

At this point, type Ctrl-X to resume booting with the modified kernel command line.

Now the node should come up normally, and finish with the normal Harvester console screen that shows the cluster and node IP addresses and status.

The the node should operate normally now but the kernel boot argument changes will not be preserved across a reboot unless you perform the next step.

5. Permanently edit the GRUB configuration file.​

At this point you need to preserve these boot argument changes.

You can do this from the console by pressing F12 and logging in, or you can use an SSH session over the network.

The changes must be made permanent by editing the GRUB configuration file grub.cfg.

The trick here is that the file to be changed is stored in a partition which is normally read-only, so the first thing you must do is to re-mount the volume to be read-write.

Start out by using the blkid command to find the device name of the correct partition:

    $ sudo -i
    # blkid -L COS_STATE
    /dev/sda4
    #

The device name will be something like /dev/sda4. The following examples assume that's the name but you should modify the commands to match what you see on your system.

Now, re-mount that volume to make it writable:

    # mount -o remount -rw /dev/sda4 /run/initramfs/cos-state

Next, edit the grub.cfg file.

    # vim /run/initramfs/cos-state/grub2/grub.cfg

Look for menuentry directives. There will be several of these; at least one as a fallback, and one for recovery. You should apply the same change to all of them.

In each of these, edit the line beginning with linux just as you did for the interactive GRUB menu, appending rd.iscsi.firmware rd.iscsi.ibft to the arguments.

Then save the changes.

It is not necessary, but probably advisable to remount that volume again to return it to its read-only state:

    # mount -o remount -ro /dev/sda4 /run/initramfs/cos-state

From this point on, these changes will persist across node reboots.

A few important notes:

• You must perform this same procedure for every node of your cluster that you are booting with iSCSI.
• These changes will be overwritten by the upgrade procedure if you upgrade your cluster to a newer version of Harvester. Therefore, if you do an upgrade, be sure to re-do the procedure to edit the grub.cfg on every node of your cluster that is booting by iSCSI.

References​

• SCSI provides an overview of SCSI and contains references to additional material.
• iSCSI provides an overview of iSCSI and contains references to additional material.
• Converged Network Adapter provides a summary of CNAs and references to additional material.
• Harvester Docuementation provides a general description of how to permanently edit kernel parameters to be used when booting a Harvester node.
• Dell PowerEdge R630 Owner's Manual This is an example of relevant vendor documentation. Other vendors such as HPE, IBM, Lenovo, etc should provide comparable documentation, though the details will vary.

Filesystem trim is a common way to release unused space in a filesystem. However, this operation is known to cause IO errors when used with Longhorn volumes that are rebuilding. For more information about the errors, see the following issues:

• Harvester: Issue 4793
• Longhorn: Issue 7103

Risks Associated with Filesystem Trim​

A consequence of the IO errors caused by filesystem trim is that VMs using affected Longhorn volumes become stuck. Imagine the VM is running critical applications, then becomes unavailable. This is significant because Harvester typically uses Longhorn volumes as VM disks. The IO errors will cause VMs to flap between running and paused states until volume rebuilding is completed.

Although the described system behavior does not affect data integrity, it might induce panic in some users. Consider the guest Kubernetes cluster scenario. In a stuck VM, the etcd service is unavailable. The effects of this failure cascade from the Kubernetes cluster becoming unavailable to services running on the cluster becoming unavailable.

How to Check If Filesystem Trim Is Enabled​

Linux​

In most Linux distributions, filesystem trim is enabled by default. You can check if the related service fstrim is enabled by running the following command:

$ systemctl status fstrim.timer
● fstrim.timer - Discard unused blocks once a week
     Loaded: loaded (/lib/systemd/system/fstrim.timer; enabled; vendor preset: enabled)
     Active: active (waiting) since Mon 2024-03-18 03:40:24 UTC; 1 week 1 day ago
    Trigger: Mon 2024-04-01 01:00:06 UTC; 5 days left
   Triggers: ● fstrim.service
       Docs: man:fstrim

Mar 18 03:40:24 harvester-cluster-01-pool1-49b619f6-tpc4v systemd[1]: Started Discard unused blocks once a week.

When the fstrim.timer service is enabled, the system periodically runs fstrim.

Windows​

You can check if filesystem trim is enabled by running the following command:

C:\> fsutil behavior query DisableDeleteNotify
NTFS DisableDeleteNotify = 0  (Allows TRIM operations to be sent to the storage device)
ReFS DisableDeleteNotify = 0  (Allows TRIM operations to be sent to the storage device)

DisableDeleteNotify = 0 indicates that TRIM operations are enabled. For more information, see fsutil behavior in the Microsoft documentation.

Risk Mitigation​

Linux​

One way to mitigate the described risks is to disable fstrim services in VMs. fstrim services is enabled by default in many modern Linux distributions. You can determine if fstrim is enabled in VMs that use affected Longhorn volumes by checking the following:

• /etc/fstab: Some root filesystems mount with the discard option.

  Example:

  /dev/mapper/rootvg-rootlv /                       xfs     defaults,discard        0 0
  

  Copy

  You can disable fstrim on the root filesystem by removing the discard option.

  /dev/mapper/rootvg-rootlv /                       xfs     defaults        0 0   <-- remove the discard option
  

  Copy

  After removing the discard option, you can remount the root filesystem using the command mount -o remount / or by rebooting the VM.

• fstrim.timer: When this service is enabled, fstrim executes weekly by default. You can either disable the service or edit the service file to prevent simultaneous fstrim execution on VMs.

  You can disable the service using the following command:

  systemctl disable fstrim.timer
  

  Copy

  To prevent simultaneous fstrim execution, use the following values in the service file (located at /usr/lib/systemd/system/fstrim.timer):

  [Timer]
  OnCalendar=weekly
  AccuracySec=1h
  Persistent=true
  RandomizedDelaySec=6000
  

  Copy

Windows​

To mitigate the described risks, you can disable TRIM operations using the following commands:

• ReFS v2

  C:\> fsutil behavior set DisableDeleteNotify ReFS 1
  

  Copy

• NTFS and ReFS v1

  C:\> fsutil behavior set DisableDeleteNotify 1
  

  Copy

Harvester calculates the resource metrics using data that is dynamically collected from the system. Host-level resource metrics are calculated and then aggregated to obtain the cluster-level metrics.

You can view resource-related metrics on the Harvester UI.

• Hosts screen: Displays host-level metrics

  

• Dashboard screen: Displays cluster-level metrics

  

CPU and Memory​

The following sections describe the data sources and calculation methods for CPU and memory resources.

• Resource capacity: Baseline data
• Resource usage: Data source for the Used field on the Hosts screen
• Resource reservation: Data source for the Reserved field on the Hosts screen

Resource Capacity​

In Kubernetes, a Node object is created for each host.

The .status.allocatable.cpu and .status.allocatable.memory represent the available CPU and Memory resources of a host.

# kubectl get nodes -A -oyaml
apiVersion: v1
items:
- apiVersion: v1
  kind: Node
  metadata:
..
      management.cattle.io/pod-limits: '{"cpu":"12715m","devices.kubevirt.io/kvm":"1","devices.kubevirt.io/tun":"1","devices.kubevirt.io/vhost-net":"1","memory":"17104951040"}'
      management.cattle.io/pod-requests: '{"cpu":"5657m","devices.kubevirt.io/kvm":"1","devices.kubevirt.io/tun":"1","devices.kubevirt.io/vhost-net":"1","ephemeral-storage":"50M","memory":"9155862208","pods":"78"}'
      node.alpha.kubernetes.io/ttl: "0"
..
    name: harv41
    resourceVersion: "2170215"
    uid: b6f5850a-2fbc-4aef-8fbe-121dfb671b67
  spec:
    podCIDR: 10.52.0.0/24
    podCIDRs:
    - 10.52.0.0/24
    providerID: rke2://harv41
  status:
    addresses:
    - address: 192.168.122.141
      type: InternalIP
    - address: harv41
      type: Hostname
    allocatable:
      cpu: "10"
      devices.kubevirt.io/kvm: 1k
      devices.kubevirt.io/tun: 1k
      devices.kubevirt.io/vhost-net: 1k
      ephemeral-storage: "149527126718"
      hugepages-1Gi: "0"
      hugepages-2Mi: "0"
      memory: 20464216Ki
      pods: "200"
    capacity:
      cpu: "10"
      devices.kubevirt.io/kvm: 1k
      devices.kubevirt.io/tun: 1k
      devices.kubevirt.io/vhost-net: 1k
      ephemeral-storage: 153707984Ki
      hugepages-1Gi: "0"
      hugepages-2Mi: "0"
      memory: 20464216Ki
      pods: "200"

Resource Usage​

CPU and memory usage data is continuously collected and stored in the NodeMetrics object. Harvester reads the data from usage.cpu and usage.memory.

# kubectl get NodeMetrics -A -oyaml
apiVersion: v1
items:
- apiVersion: metrics.k8s.io/v1beta1
  kind: NodeMetrics
  metadata:
...
    name: harv41
  timestamp: "2024-01-23T12:04:44Z"
  usage:
    cpu: 891736742n
    memory: 9845008Ki
  window: 10.149s

Resource Reservation​

Harvester dynamically calculates the resource limits and requests of all pods running on a host, and updates the information to the annotations of the NodeMetrics object.

      management.cattle.io/pod-limits: '{"cpu":"12715m",...,"memory":"17104951040"}'
      management.cattle.io/pod-requests: '{"cpu":"5657m",...,"memory":"9155862208"}'

For more information, see Requests and Limits in the Kubernetes documentation.

Storage​

Longhorn is the default Container Storage Interface (CSI) driver of Harvester, providing storage management features such as distributed block storage and tiering.

Reserved Storage in Longhorn​

Longhorn allows you to specify the percentage of disk space that is not allocated to the default disk on each new Longhorn node. The default value is "30". For more information, see Storage Reserved Percentage For Default Disk in the Longhorn documentation.

Depending on the disk size, you can modify the default value using the embedded Longhorn UI.

Data Sources and Calculation​

Harvester uses the following data to calculate metrics for storage resources.

• Sum of the storageMaximum values of all disks (status.diskStatus.disk-name): Total storage capacity

• Total storage capacity - Sum of the storageAvailable values of all disks (status.diskStatus.disk-name): Data source for the Used field on the Hosts screen

• Sum of the storageReserved values of all disks (spec.disks): Data source for the Reserved field on the Hosts screen

# kubectl get nodes.longhorn.io -n longhorn-system -oyaml

apiVersion: v1
items:
- apiVersion: longhorn.io/v1beta2
  kind: Node
  metadata:
..
    name: harv41
    namespace: longhorn-system
..
  spec:
    allowScheduling: true
    disks:
      default-disk-ef11a18c36b01132:
        allowScheduling: true
        diskType: filesystem
        evictionRequested: false
        path: /var/lib/harvester/defaultdisk
        storageReserved: 24220101427
        tags: []
..
  status:
..
    diskStatus:
      default-disk-ef11a18c36b01132:
..
        diskType: filesystem
        diskUUID: d2788933-8817-44c6-b688-dee414cc1f73
        scheduledReplica:
          pvc-95561210-c39c-4c2e-ac9a-4a9bd72b3100-r-20affeca: 2147483648
          pvc-9e83b2dc-6a4b-4499-ba70-70dc25b2d9aa-r-4ad05c86: 32212254720
          pvc-bc25be1e-ca4e-4818-a16d-48353a0f2f96-r-c7b88c60: 3221225472
          pvc-d9d3e54d-8d67-4740-861e-6373f670f1e4-r-f4c7c338: 2147483648
          pvc-e954b5fe-bbd7-4d44-9866-6ff6684d5708-r-ba6b87b6: 5368709120
        storageAvailable: 77699481600
        storageMaximum:   80733671424
        storageScheduled: 45097156608
    region: ""
    snapshotCheckStatus: {}
    zone: ""

The Longhorn documentation provides best practice recommendations for deploying Longhorn in production environments. Before configuring workloads, ensure that you have set up the following basic requirements for optimal disk performance.

• SATA/NVMe SSDs or disk drives with similar performance
• 10 Gbps network bandwidth between nodes
• Dedicated Priority Classes for system-managed and user-deployed Longhorn components

The following sections outline other recommendations for achieving optimal disk performance.

IO Performance​

• Storage network: Use a dedicated storage network to improve IO performance and stability.

• Longhorn disk: Use a dedicated disk for Longhorn storage instead of using the root disk.

• Replica count: Set the default replica count to "2" to achieve data availability with better disk space usage or less impact to system performance. This practice is especially beneficial to data-intensive applications.

• Storage tag: Use storage tags to define storage tiering for data-intensive applications. For example, only high-performance disks can be used for storing performance-sensitive data. You can either add disks with tags or create StorageClasses with tags.

• Data locality: Use best-effort as the default data locality of Longhorn Storage Classes.

  For applications that support data replication (for example, a distributed database), you can use the strict-local option to ensure that only one replica is created for each volume. This practice prevents the extra disk space usage and IO performance overhead associated with volume replication.

  For data-intensive applications, you can use pod scheduling functions such as node selector or taint toleration. These functions allow you to schedule the workload to a specific storage-tagged node together with one replica.

Space Efficiency​

• Recurring snapshots: Periodically clean up system-generated snapshots and retain only the number of snapshots that makes sense for your implementation.

  For applications with replication capability, periodically delete all types of snapshots.

Disaster Recovery​

• Recurring backups: Create recurring backup jobs for mission-critical application volumes.

• System backup: Run periodic system backups.

In Harvester, the VM Live Migration is well supported by the UI. Please refer to Harvester VM Live Migration for more details.

The VM Live Migration process is finished smoothly in most cases. However, sometimes the migration may get stuck and not end as expected.

This article dives into the VM Live Migration process in more detail. There are three main parts:

• General Process of VM Live Migration
• VM Live Migration Strategies
• VM Live Migration Configurations

Related issues:

• Migration should show the proper status and progress in the UI
• VM Migration policy and status

General Process of VM Live Migration​

Starting a Migration from Harvester UI​

1. Go to the Virtual Machines page.
2. Find the virtual machine that you want to migrate and select ⋮ > Migrate.
3. Choose the node to which you want to migrate the virtual machine and select Apply.

After successfully selecting Apply, a CRD VirtualMachineInstanceMigration object is created, and the related controller/operator will start the process.

Migration CRD Object​

You can also create the CRD VirtualMachineInstanceMigration object manually via kubectl or other tools.

The example below starts a migration process for a virtual machine instance (VMI) new-vm.

apiVersion: kubevirt.io/v1
kind: VirtualMachineInstanceMigration
metadata:
  name: migration-job
spec:
  vmiName: new-vm

Under the hood, the open source projects Kubevirt, Libvirt, QEMU, ... perform most of the VM Live Migration. References.

Migration Status Reporting​

When starting a virtual machine instance (VMI), it has also been calculated whether the machine is live migratable. The result is being stored in the VMI VMI.status.conditions. The calculation can be based on multiple parameters of the VMI, however, at the moment, the calculation is largely based on the Access Mode of the VMI volumes. Live migration is only permitted when the volume access mode is set to ReadWriteMany. Requests to migrate a non-LiveMigratable VMI will be rejected.

The reported Migration Method is also being calculated during VMI start. BlockMigration indicates that some of the VMI disks require copying from the source to the destination. LiveMigration means that only the instance memory will be copied.

Status:
  Conditions:
    Status: True
    Type: LiveMigratable
  Migration Method: BlockMigration

Migration Status​

The migration progress status is reported in VMI.status. Most importantly, it indicates whether the migration has been completed or failed.

Below is an example of a successful migration.

Migration State:
    Completed:        true
    End Timestamp:    2019-03-29T03:37:52Z
    Migration Config:
      Completion Timeout Per GiB:  800
      Progress Timeout:             150
    Migration UID:                  c64d4898-51d3-11e9-b370-525500d15501
    Source Node:                    node02
    Start Timestamp:                2019-03-29T04:02:47Z
    Target Direct Migration Node Ports:
      35001:                      0
      41068:                      49152
      38284:                      49153
    Target Node:                  node01
    Target Node Address:          10.128.0.46
    Target Node Domain Detected:  true
    Target Pod:                   virt-launcher-testvmimcbjgw6zrzcmp8wpddvztvzm7x2k6cjbdgktwv8tkq

VM Live Migration Strategies​

VM Live Migration is a process during which a running Virtual Machine Instance moves to another compute node while the guest workload continues to run and remain accessible.

Understanding Different VM Live Migration Strategies​

VM Live Migration is a complex process. During a migration, the source VM needs to transfer its whole state (mainly RAM) to the target VM. If there are enough resources available, such as network bandwidth and CPU power, migrations should converge nicely. If this is not the scenario, however, the migration might get stuck without an ability to progress.

The main factor that affects migrations from the guest perspective is its dirty rate, which is the rate by which the VM dirties memory. Guests with high dirty rate lead to a race during migration. On the one hand, memory would be transferred continuously to the target, and on the other, the same memory would get dirty by the guest. On such scenarios, one could consider to use more advanced migration strategies. Refer to Understanding different migration strategies for more details.

There are 3 VM Live Migration strategies/policies:

VM Live Migration Strategy: Pre-copy​

Pre-copy is the default strategy. It should be used for most cases.

The way it works is as following:

1. The target VM is created, but the guest keeps running on the source VM.
2. The source starts sending chunks of VM state (mostly memory) to the target. This continues until all of the state has been transferred to the target.
3. The guest starts executing on the target VM. 4. The source VM is being removed.

Pre-copy is the safest and fastest strategy for most cases. Furthermore, it can be easily cancelled, can utilize multithreading, and more. If there is no real reason to use another strategy, this is definitely the strategy to go with.

However, on some cases migrations might not converge easily, that is, by the time the chunk of source VM state would be received by the target VM, it would already be mutated by the source VM (which is the VM the guest executes on). There are many reasons for migrations to fail converging, such as a high dirty-rate or low resources like network bandwidth and CPU. On such scenarios, see the following alternative strategies below.

VM Live Migration Strategy: Post-copy​

The way post-copy migrations work is as following:

1. The target VM is created.
2. The guest is being run on the target VM.
3. The source starts sending chunks of VM state (mostly memory) to the target.
4. When the guest, running on the target VM, would access memory: 1. If the memory exists on the target VM, the guest can access it. 2. Otherwise, the target VM asks for a chunk of memory from the source VM.
5. Once all of the memory state is updated at the target VM, the source VM is being removed.

The main idea here is that the guest starts to run immediately on the target VM. This approach has advantages and disadvantages:

Advantages:

• The same memory chink is never being transferred twice. This is possible due to the fact that with post-copy it doesn't matter that a page had been dirtied since the guest is already running on the target VM.
• This means that a high dirty-rate has much less effect.
• Consumes less network bandwidth.

Disadvantages:

• When using post-copy, the VM state has no one source of truth. When the guest (running on the target VM) writes to memory, this memory is one part of the guest's state, but some other parts of it may still be updated only at the source VM. This situation is generally dangerous, since, for example, if either the target or guest VMs crash the state cannot be recovered.
• Slow warmup: when the guest starts executing, no memory is present at the target VM. Therefore, the guest would have to wait for a lot of memory in a short period of time.
• Slower than pre-copy on most cases.
• Harder to cancel a migration.

VM Live Migration Strategy: Auto-converge​

Auto-converge is a technique to help pre-copy migrations converge faster without changing the core algorithm of how the migration works.

Since a high dirty-rate is usually the most significant factor for migrations to not converge, auto-converge simply throttles the guest's CPU. If the migration would converge fast enough, the guest's CPU would not be throttled or throttled negligibly. But, if the migration would not converge fast enough, the CPU would be throttled more and more as time goes.

This technique dramatically increases the probability of the migration converging eventually.

Observe the VM Live Migration Progress and Result​

Migration Timeouts​

Depending on the type, the live migration process will copy virtual machine memory pages and disk blocks to the destination. During this process non-locked pages and blocks are being copied and become free for the instance to use again. To achieve a successful migration, it is assumed that the instance will write to the free pages and blocks (pollute the pages) at a lower rate than these are being copied.

Completion Time​

In some cases the virtual machine can write to different memory pages / disk blocks at a higher rate than these can be copied, which will prevent the migration process from completing in a reasonable amount of time. In this case, live migration will be aborted if it is running for a long period of time. The timeout is calculated base on the size of the VMI, it's memory and the ephemeral disks that are needed to be copied. The configurable parameter completionTimeoutPerGiB, which defaults to 800s is the time for GiB of data to wait for the migration to be completed before aborting it. A VMI with 8Gib of memory will time out after 6400 seconds.

Progress Timeout​

A VM Live Migration will also be aborted when it notices that copying memory doesn't make any progress. The time to wait for live migration to make progress in transferring data is configurable by the progressTimeout parameter, which defaults to 150 seconds.

VM Live Migration Configurations​

Changing Cluster Wide Migration Limits​

KubeVirt puts some limits in place so that migrations don't overwhelm the cluster. By default, it is to only run 5 migrations in parallel with an additional limit of a maximum of 2 outbound migrations per node. Finally, every migration is limited to a bandwidth of 64MiB/s.

You can change these values in the kubevirt CR:

    apiVersion: kubevirt.io/v1
    kind: Kubevirt
    metadata:
      name: kubevirt
      namespace: kubevirt
    spec:
      configuration:
        migrations:
          parallelMigrationsPerCluster: 5
          parallelOutboundMigrationsPerNode: 2
          bandwidthPerMigration: 64Mi
          completionTimeoutPerGiB: 800
          progressTimeout: 150
          disableTLS: false
          nodeDrainTaintKey: "kubevirt.io/drain"
          allowAutoConverge: false ---------------------> related to: Auto-converge
          allowPostCopy: false -------------------------> related to: Post-copy
          unsafeMigrationOverride: false

Remember that most of these configurations can be overridden and fine-tuned to a specified group of VMs. For more information, please refer to the Migration Policies section below.

Migration Policies​

Migration policies provides a new way of applying migration configurations to Virtual Machines. The policies can refine Kubevirt CR's MigrationConfiguration that sets the cluster-wide migration configurations. This way, the cluster-wide settings default how the migration policy can be refined (i.e., changed, removed, or added).

Remember that migration policies are in version v1alpha1. This means that this API is not fully stable yet and that APIs may change in the future.

Migration Configurations​

Currently, the MigrationPolicy spec only includes the following configurations from Kubevirt CR's MigrationConfiguration. (In the future, more configurations that aren't part of Kubevirt CR will be added):

apiVersion: migrations.kubevirt.io/v1alpha1
kind: MigrationPolicy
  spec:
    allowAutoConverge: true
    bandwidthPerMigration: 217Ki
    completionTimeoutPerGiB: 23
    allowPostCopy: false

All the above fields are optional. When omitted, the configuration will be applied as defined in KubevirtCR's MigrationConfiguration. This way, KubevirtCR will serve as a configurable set of defaults for both VMs that are not bound to any MigrationPolicy and VMs that are bound to a MigrationPolicy that does not define all fields of the configurations.

Matching Policies to VMs​

Next in the spec are the selectors defining the group of VMs to apply the policy. The options to do so are the following.

This policy applies to the VMs in namespaces that have all the required labels:

apiVersion: migrations.kubevirt.io/v1alpha1
kind: MigrationPolicy
  spec:
  selectors:
    namespaceSelector:
      hpc-workloads: true       # Matches a key and a value

The policy below applies to the VMs that have all the required labels:

apiVersion: migrations.kubevirt.io/v1alpha1
kind: MigrationPolicy
  spec:
  selectors:
    virtualMachineInstanceSelector:
      workload-type: db       # Matches a key and a value

References​

Documents​

Libvirt Guest Migration​

Libvirt has a chapter to describe the pricipal of VM/Guest Live Migration.

https://libvirt.org/migration.html

Kubevirt Live Migration​

https://kubevirt.io/user-guide/operations/live_migration/

Source Code​

The VM Live Migration related configuration options are passed to each layer correspondingly.

Kubevirt​

https://github.com/kubevirt/kubevirt/blob/d425593ae392111dab80403ef0cde82625e37653/pkg/virt-launcher/virtwrap/live-migration-source.go#L103

...
import "libvirt.org/go/libvirt"

...

func generateMigrationFlags(isBlockMigration, migratePaused bool, options *cmdclient.MigrationOptions) libvirt.DomainMigrateFlags {
...
    if options.AllowAutoConverge {
        migrateFlags |= libvirt.MIGRATE_AUTO_CONVERGE
    }
    if options.AllowPostCopy {
        migrateFlags |= libvirt.MIGRATE_POSTCOPY
    }
...
}

Go Package Libvirt​

https://pkg.go.dev/libvirt.org/go/libvirt

const (
...
    MIGRATE_AUTO_CONVERGE                 = DomainMigrateFlags(C.VIR_MIGRATE_AUTO_CONVERGE)
    MIGRATE_RDMA_PIN_ALL                  = DomainMigrateFlags(C.VIR_MIGRATE_RDMA_PIN_ALL)
    MIGRATE_POSTCOPY                      = DomainMigrateFlags(C.VIR_MIGRATE_POSTCOPY)
...
)

Libvirt​

https://github.com/libvirt/libvirt/blob/bfe53e9145cd5996a791c5caff0686572b850f82/include/libvirt/libvirt-domain.h#L1030

    /* Enable algorithms that ensure a live migration will eventually converge.
     * This usually means the domain will be slowed down to make sure it does
     * not change its memory faster than a hypervisor can transfer the changed
     * memory to the destination host. VIR_MIGRATE_PARAM_AUTO_CONVERGE_*
     * parameters can be used to tune the algorithm.
     *
     * Since: 1.2.3
     */
    VIR_MIGRATE_AUTO_CONVERGE = (1 << 13),
...
   /* Setting the VIR_MIGRATE_POSTCOPY flag tells libvirt to enable post-copy
     * migration. However, the migration will start normally and
     * virDomainMigrateStartPostCopy needs to be called to switch it into the
     * post-copy mode. See virDomainMigrateStartPostCopy for more details.
     *
     * Since: 1.3.3
     */
    VIR_MIGRATE_POSTCOPY = (1 << 15),

Starting with Harvester v1.2.0, it offers the capability to install a Container Storage Interface (CSI) in your Harvester cluster. This allows you to leverage external storage for the Virtual Machine's non-system data disk, giving you the flexibility to use different drivers tailored for specific needs, whether it's for performance optimization or seamless integration with your existing in-house storage solutions.

It's important to note that, despite this enhancement, the provisioner for the Virtual Machine (VM) image in Harvester still relies on Longhorn. Prior to version 1.2.0, Harvester exclusively supported Longhorn for storing VM data and did not offer support for external storage as a destination for VM data.

One of the options for integrating external storage with Harvester is Rook, an open-source cloud-native storage orchestrator. Rook provides a robust platform, framework, and support for Ceph storage, enabling seamless integration with cloud-native environments.

Ceph is a software-defined distributed storage system that offers versatile storage capabilities, including file, block, and object storage. It is designed for large-scale production clusters and can be deployed effectively in such environments.

Rook simplifies the deployment and management of Ceph, offering self-managing, self-scaling, and self-healing storage services. It leverages Kubernetes resources to automate the deployment, configuration, provisioning, scaling, upgrading, and monitoring of Ceph.

In this article, we will walk you through the process of installing, configuring, and utilizing Rook to use storage from an existing external Ceph cluster as a data disk for a VM within the Harvester environment.

Install Harvester Cluster​

Harvester's operating system follows an immutable design, meaning that most OS files revert to their pre-configured state after a reboot. To accommodate Rook Ceph's requirements, you need to add specific persistent paths to the os.persistentStatePaths section in the Harvester configuration. These paths include:

os:
  persistent_state_paths:
    - /var/lib/rook
    - /var/lib/ceph
  modules:
    - rbd
    - nbd

After the cluster is installed, refer to How can I access the kubeconfig file of the Harvester cluster? to get the kubeconfig of the Harvester cluster.

Install Rook to Harvester​

Install Rook to the Harvester cluster by referring to Rook Quickstart.

curl -fsSLo rook.tar.gz https://github.com/rook/rook/archive/refs/tags/v1.12.2.tar.gz \
  && tar -zxf rook.tar.gz && cd rook-1.12.2/deploy/examples
# apply configurations ref: https://rook.github.io/docs/rook/v1.12/Getting-Started/example-configurations/
kubectl apply -f crds.yaml -f common.yaml -f operator.yaml
kubectl -n rook-ceph wait --for=condition=Available deploy rook-ceph-operator --timeout=10m

Using an existing external Ceph cluster​

1. Run the python script create-external-cluster-resources.py in the existing external Ceph cluster for creating all users and keys.

# script help ref: https://www.rook.io/docs/rook/v1.12/CRDs/Cluster/external-cluster/#1-create-all-users-and-keys
curl -s https://raw.githubusercontent.com/rook/rook/v1.12.2/deploy/examples/create-external-cluster-resources.py > create-external-cluster-resources.py
python3 create-external-cluster-resources.py --rbd-data-pool-name <pool_name> --namespace rook-ceph-external --format bash

2. Copy the Bash output.

Example output:

export NAMESPACE=rook-ceph-external
export ROOK_EXTERNAL_FSID=b3b47828-4c60-11ee-be38-51902f85c805
export ROOK_EXTERNAL_USERNAME=client.healthchecker
export ROOK_EXTERNAL_CEPH_MON_DATA=ceph-1=192.168.5.99:6789
export ROOK_EXTERNAL_USER_SECRET=AQDd6/dkFyu/IhAATv/uCMbHtWk4AYK2KXzBhQ==
export ROOK_EXTERNAL_DASHBOARD_LINK=https://192.168.5.99:8443/
export CSI_RBD_NODE_SECRET=AQDd6/dk2HsjIxAA06Yw9UcOg0dfwV/9IFBRhA==
export CSI_RBD_NODE_SECRET_NAME=csi-rbd-node
export CSI_RBD_PROVISIONER_SECRET=AQDd6/dkEY1kIxAAAzrXZnVRf4x+wDUz1zyaQg==
export CSI_RBD_PROVISIONER_SECRET_NAME=csi-rbd-provisioner
export MONITORING_ENDPOINT=192.168.5.99
export MONITORING_ENDPOINT_PORT=9283
export RBD_POOL_NAME=test
export RGW_POOL_PREFIX=default

3. Consume the external Ceph cluster resources on the Harvester cluster.

# Paste the above output from create-external-cluster-resources.py into import-env.sh
vim import-env.sh
source import-env.sh
# this script will create a StorageClass ceph-rbd
source import-external-cluster.sh

kubectl apply -f common-external.yaml
kubectl apply -f cluster-external.yaml
# wait for all pods to become Ready
watch 'kubectl --namespace rook-ceph get pods'

4. Create the VolumeSnapshotClass csi-rbdplugin-snapclass-external.

cat >./csi/rbd/snapshotclass-external.yaml <<EOF
---
apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshotClass
metadata:
  name: csi-rbdplugin-snapclass-external
driver: rook-ceph.rbd.csi.ceph.com # driver:namespace:operator
parameters:
  clusterID: rook-ceph-external # namespace:cluster
  csi.storage.k8s.io/snapshotter-secret-name: rook-csi-rbd-provisioner
  csi.storage.k8s.io/snapshotter-secret-namespace: rook-ceph-external # namespace:cluster
deletionPolicy: Delete
EOF

kubectl apply -f ./csi/rbd/snapshotclass-external.yaml

Configure Harvester Cluster​

Before you can make use of Harvester's Backup & Snapshot features, you need to set up some essential configurations through the Harvester csi-driver-config setting. To set up these configurations, follow these steps:

1. Login to the Harvester UI, then navigate to Advanced > Settings.
2. Find and select csi-driver-config, and then click on the ⋮ > Edit Setting to access the configuration options.
3. In the settings, set the Provisioner to rook-ceph.rbd.csi.ceph.com.
4. Next, specify the Volume Snapshot Class Name as csi-rbdplugin-snapclass-external. This setting points to the name of the VolumeSnapshotClass used for creating volume snapshots or VM snapshots.

Use Rook Ceph in Harvester​

After successfully configuring these settings, you can proceed to utilize the Rook Ceph StorageClass, which is named rook-ceph-block for the internal Ceph cluster or named ceph-rbd for the external Ceph cluster. You can apply this StorageClass when creating an empty volume or adding a new block volume to a VM, enhancing your Harvester cluster's storage capabilities.

With these configurations in place, your Harvester cluster is ready to make the most of the Rook Ceph storage integration.