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Updating OpenShift Virtualization

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OpenShift Virtualization on RHEL 9

OpenShift Virtualization 4.17 is based on Red Hat Enterprise Linux (RHEL) 9. You can update to OpenShift Virtualization 4.17 from a version that was based on RHEL 8 by following the standard OpenShift Virtualization update procedure. No additional steps are required.

As in previous versions, you can perform the update without disrupting running workloads. OpenShift Virtualization 4.17 supports live migration from RHEL 8 nodes to RHEL 9 nodes.

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RHEL 9 machine type

All VM templates that are included with OpenShift Virtualization now use the RHEL 9 machine type by default: machineType: pc-q35-rhel9.<y>.0, where <y> is a single digit corresponding to the latest minor version of RHEL 9. For example, the value pc-q35-rhel9.2.0 is used for RHEL 9.2.

Updating OpenShift Virtualization does not change the machineType value of any existing VMs. These VMs continue to function as they did before the update. You can optionally change a VM’s machine type so that it can benefit from RHEL 9 improvements.

Before you change a VM’s machineType value, you must shut down the VM.
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About updating OpenShift Virtualization

  • Operator Lifecycle Manager (OLM) manages the lifecycle of the OpenShift Virtualization Operator. The Marketplace Operator, which is deployed during Red Hat OpenShift Service on AWS installation, makes external Operators available to your cluster.

  • OLM provides z-stream and minor version updates for OpenShift Virtualization. Minor version updates become available when you update Red Hat OpenShift Service on AWS to the next minor version. You cannot update OpenShift Virtualization to the next minor version without first updating Red Hat OpenShift Service on AWS.

  • OpenShift Virtualization subscriptions use a single update channel that is named stable. The stable channel ensures that your OpenShift Virtualization and Red Hat OpenShift Service on AWS versions are compatible.

  • If your subscription’s approval strategy is set to Automatic, the update process starts as soon as a new version of the Operator is available in the stable channel. It is highly recommended to use the Automatic approval strategy to maintain a supportable environment. Each minor version of OpenShift Virtualization is only supported if you run the corresponding Red Hat OpenShift Service on AWS version. For example, you must run OpenShift Virtualization 4.17 on Red Hat OpenShift Service on AWS 4.17.

    • Though it is possible to select the Manual approval strategy, this is not recommended because it risks the supportability and functionality of your cluster. With the Manual approval strategy, you must manually approve every pending update. If Red Hat OpenShift Service on AWS and OpenShift Virtualization updates are out of sync, your cluster becomes unsupported.

  • The amount of time an update takes to complete depends on your network connection. Most automatic updates complete within fifteen minutes.

  • Updating OpenShift Virtualization does not interrupt network connections.

  • Data volumes and their associated persistent volume claims are preserved during update.

If you have virtual machines running that use AWS Elastic Block Store (EBS) storage, they cannot be live migrated and might block an Red Hat OpenShift Service on AWS cluster update.

As a workaround, you can reconfigure the virtual machines so that they can be powered off automatically during a cluster update. Set the evictionStrategy field to None and the runStrategy field to Always.
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About workload updates

When you update OpenShift Virtualization, virtual machine workloads, including libvirt, virt-launcher, and qemu, update automatically if they support live migration.

Each virtual machine has a virt-launcher pod that runs the virtual machine instance (VMI). The virt-launcher pod runs an instance of libvirt, which is used to manage the virtual machine (VM) process.

You can configure how workloads are updated by editing the spec.workloadUpdateStrategy stanza of the HyperConverged custom resource (CR). There are two available workload update methods: LiveMigrate and Evict.

Because the Evict method shuts down VMI pods, only the LiveMigrate update strategy is enabled by default.

When LiveMigrate is the only update strategy enabled:

  • VMIs that support live migration are migrated during the update process. The VM guest moves into a new pod with the updated components enabled.

  • VMIs that do not support live migration are not disrupted or updated.

    • If a VMI has the LiveMigrate eviction strategy but does not support live migration, it is not updated.

If you enable both LiveMigrate and Evict:

  • VMIs that support live migration use the LiveMigrate update strategy.

  • VMIs that do not support live migration use the Evict update strategy. If a VMI is controlled by a VirtualMachine object that has runStrategy: Always set, a new VMI is created in a new pod with updated components.

Migration attempts and timeouts

When updating workloads, live migration fails if a pod is in the Pending state for the following periods:

5 minutes

If the pod is pending because it is Unschedulable.

15 minutes

If the pod is stuck in the pending state for any reason.

When a VMI fails to migrate, the virt-controller tries to migrate it again. It repeats this process until all migratable VMIs are running on new virt-launcher pods. If a VMI is improperly configured, however, these attempts can repeat indefinitely.

Each attempt corresponds to a migration object. Only the five most recent attempts are held in a buffer. This prevents migration objects from accumulating on the system while retaining information for debugging.
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Configuring workload update methods

You can configure workload update methods by editing the HyperConverged custom resource (CR).

Prerequisites

  • To use live migration as an update method, you must first enable live migration in the cluster.

    If a VirtualMachineInstance CR contains evictionStrategy: LiveMigrate and the virtual machine instance (VMI) does not support live migration, the VMI will not update.
Procedure

  1. To open the HyperConverged CR in your default editor, run the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv

  2. Edit the workloadUpdateStrategy stanza of the HyperConverged CR. For example:

    apiVersion: hco.kubevirt.io/v1beta1
kind: HyperConverged
metadata:
  name: kubevirt-hyperconverged
spec:
  workloadUpdateStrategy:
    workloadUpdateMethods: (1)
    - LiveMigrate (2)
    - Evict (3)
    batchEvictionSize: 10 (4)
    batchEvictionInterval: "1m0s" (5)
# ...
    1 The methods that can be used to perform automated workload updates. The available values are LiveMigrate and Evict. If you enable both options as shown in this example, updates use LiveMigrate for VMIs that support live migration and Evict for any VMIs that do not support live migration. To disable automatic workload updates, you can either remove the workloadUpdateStrategy stanza or set workloadUpdateMethods: [] to leave the array empty.
    2 The least disruptive update method. VMIs that support live migration are updated by migrating the virtual machine (VM) guest into a new pod with the updated components enabled. If LiveMigrate is the only workload update method listed, VMIs that do not support live migration are not disrupted or updated.
    3 A disruptive method that shuts down VMI pods during upgrade. Evict is the only update method available if live migration is not enabled in the cluster. If a VMI is controlled by a VirtualMachine object that has runStrategy: Always configured, a new VMI is created in a new pod with updated components.
    4 The number of VMIs that can be forced to be updated at a time by using the Evict method. This does not apply to the LiveMigrate method.
    5 The interval to wait before evicting the next batch of workloads. This does not apply to the LiveMigrate method.

    You can configure live migration limits and timeouts by editing the spec.liveMigrationConfig stanza of the HyperConverged CR.

  3. To apply your changes, save and exit the editor.

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Approving pending Operator updates

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Manually approving a pending Operator update

If an installed Operator has the approval strategy in its subscription set to Manual, when new updates are released in its current update channel, the update must be manually approved before installation can begin.

Prerequisites

  • An Operator previously installed using Operator Lifecycle Manager (OLM).

Procedure

  1. In the Administrator perspective of the Red Hat OpenShift Service on AWS web console, navigate to Operators → Installed Operators.

  2. Operators that have a pending update display a status with Upgrade available. Click the name of the Operator you want to update.

  3. Click the Subscription tab. Any updates requiring approval are displayed next to Upgrade status. For example, it might display 1 requires approval.

  4. Click 1 requires approval, then click Preview Install Plan.

  5. Review the resources that are listed as available for update. When satisfied, click Approve.

  6. Navigate back to the Operators → Installed Operators page to monitor the progress of the update. When complete, the status changes to Succeeded and Up to date.

Monitoring update status

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Monitoring OpenShift Virtualization upgrade status

To monitor the status of a OpenShift Virtualization Operator upgrade, watch the cluster service version (CSV) PHASE. You can also monitor the CSV conditions in the web console or by running the command provided here.

The PHASE and conditions values are approximations that are based on available information.
Prerequisites

  • Log in to the cluster as a user with the cluster-admin role.

  • Install the OpenShift CLI (oc).

Procedure

  1. Run the following command:

    $ oc get csv -n openshift-cnv

  2. Review the output, checking the PHASE field. For example:

    Example output
    VERSION  REPLACES                                        PHASE
4.9.0    kubevirt-hyperconverged-operator.v4.8.2         Installing
4.9.0    kubevirt-hyperconverged-operator.v4.9.0         Replacing

  3. Optional: Monitor the aggregated status of all OpenShift Virtualization component conditions by running the following command:

    $ oc get hyperconverged kubevirt-hyperconverged -n openshift-cnv \
  -o=jsonpath='{range .status.conditions[*]}{.type}{"\t"}{.status}{"\t"}{.message}{"\n"}{end}'

    A successful upgrade results in the following output:

    Example output
    ReconcileComplete  True  Reconcile completed successfully
Available          True  Reconcile completed successfully
Progressing        False Reconcile completed successfully
Degraded           False Reconcile completed successfully
Upgradeable        True  Reconcile completed successfully
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Viewing outdated OpenShift Virtualization workloads

You can view a list of outdated workloads by using the CLI.

If there are outdated virtualization pods in your cluster, the OutdatedVirtualMachineInstanceWorkloads alert fires.
Procedure

  • To view a list of outdated virtual machine instances (VMIs), run the following command:

    $ oc get vmi -l kubevirt.io/outdatedLauncherImage --all-namespaces

Configure workload updates to ensure that VMIs update automatically.

Additional resources