Updating a cluster using the web console | Updating clusters

Prerequisites
Performing a canary rollout update
Updating a cluster by using the web console
Changing the update server by using the web console

You can update, or upgrade, an OpenShift Container Platform cluster by using the web console. The following steps update a cluster within a minor version. You can use the same instructions for updating a cluster between minor versions.

Because of the difficulty of changing update channels by using oc, use the web console to change the update channel. It is recommended to complete the update process within the web console. You can follow the steps in Updating a cluster using the CLI to complete the update after you change to a 4.8 channel.

Prerequisites

Have access to the cluster as a user with admin privileges. See Using RBAC to define and apply permissions.
Have a recent etcd backup in case your update fails and you must restore your cluster to a previous state.
Ensure all Operators previously installed through Operator Lifecycle Manager (OLM) are updated to their latest version in their latest channel. Updating the Operators ensures they have a valid update path when the default OperatorHub catalogs switch from the current minor version to the next during a cluster update. See Updating installed Operators for more information.
Ensure that all machine config pools (MCPs) are running and not paused. Nodes associated with a paused MCP are skipped during the update process. You can pause the MCPs if you are performing a canary rollout update strategy.
If your cluster uses manually maintained credentials, ensure that the Cloud Credential Operator (CCO) is in an upgradeable state. For more information, see Upgrading clusters with manually maintained credentials for AWS, Azure, or GCP.
If you run an Operator or you have configured any application with the pod disruption budget, you might experience an interruption during the upgrade process. If minAvailable is set to 1 in PodDisruptionBudget, the nodes are drained to apply pending machine configs which might block the eviction process. If several nodes are rebooted, all the pods might run on only one node, and the PodDisruptionBudget field can prevent the node drain.

When an update is failing to complete, the Cluster Version Operator (CVO) reports the status of any blocking components while attempting to reconcile the update. Rolling your cluster back to a previous version is not supported. If your update is failing to complete, contact Red Hat support.
Using the unsupportedConfigOverrides section to modify the configuration of an Operator is unsupported and might block cluster updates. You must remove this setting before you can update your cluster.

Additional resources

Support policy for unmanaged Operators

Performing a canary rollout update

In some specific use cases, you might want a more controlled update process where you do not want specific nodes updated concurrently with the rest of the cluster. These use cases include, but are not limited to:

You have mission-critical applications that you do not want unavailable during the update. You can slowly test the applications on your nodes in small batches after the update.
You have a small maintenance window that does not allow the time for all nodes to be updated, or you have multiple maintenance windows.

The rolling update process is not a typical update workflow. With larger clusters, it can be a time-consuming process that requires you execute multiple commands. This complexity can result in errors that can affect the entire cluster. It is recommended that you carefully consider whether your organization wants to use a rolling update and carefully plan the implementation of the process before you start.

The rolling update process described in this topic involves:

Creating one or more custom machine config pools (MCPs).
Labeling each node that you do not want to update immediately to move those nodes to the custom MCPs.
Pausing those custom MCPs, which prevents updates to those nodes.
Performing the cluster update.
Unpausing one custom MCP, which triggers the update on those nodes.
Testing the applications on those nodes to make sure the applications work as expected on those newly-updated nodes.
Optionally removing the custom labels from the remaining nodes in small batches and testing the applications on those nodes.

Pausing an MCP prevents the Machine Config Operator from applying any configuration changes on the associated nodes. Pausing an MCP also prevents any automatically-rotated certificates from being pushed to the associated nodes, including the automatic CA rotation of the kube-apiserver-to-kubelet-signer CA certificate. If the MCP is paused when the kube-apiserver-to-kubelet-signer CA certificate expires and the MCO attempts to automatically renew the certificate, the new certificate is created but not applied across the nodes in the respective machine config pool. This causes failure in multiple oc commands, including but not limited to oc debug, oc logs, oc exec, and oc attach. Pausing an MCP should be done with careful consideration about the kube-apiserver-to-kubelet-signer CA certificate expiration and for short periods of time only.

If you want to use the canary rollout update process, see Performing a canary rollout update.

Updating a cluster by using the web console

If updates are available, you can update your cluster from the web console.

You can find information about available OpenShift Container Platform advisories and updates in the errata section of the Customer Portal.

Prerequisites

Have access to the web console as a user with admin privileges.

Procedure

From the web console, click Administration → Cluster Settings and review the contents of the Details tab.
For production clusters, ensure that the Channel is set to the correct channel for the version that you want to update to, such as stable-4.8.

For production clusters, you must subscribe to a stable-* or fast-* channel.
- If the Update status is not Updates available, you cannot update your cluster.
- Select channel indicates the cluster version that your cluster is running or is updating to.

Select a version to update to, and click Save.

The Input channel Update status changes to Update to <product-version> in progress, and you can review the progress of the cluster update by watching the progress bars for the Operators and nodes.

If you are upgrading your cluster to the next minor version, like version 4.y to 4.(y+1), it is recommended to confirm your nodes are updated before deploying workloads that rely on a new feature. Any pools with worker nodes that are not yet updated are displayed on the Cluster Settings page.

After the update completes and the Cluster Version Operator refreshes the available updates, check if more updates are available in your current channel.
- If updates are available, continue to perform updates in the current channel until you can no longer update.
- If no updates are available, change the Channel to the stable-* or fast-* channel for the next minor version, and update to the version that you want in that channel.
You might need to perform several intermediate updates until you reach the version that you want.

Changing the update server by using the web console

Changing the update server is optional. If you have an OpenShift Update Service (OSUS) installed and configured locally, you must set the URL for the server as the upstream to use the local server during updates.

Procedure

Navigate to Administration → Cluster Settings, click version.
Click the YAML tab and then edit the upstream parameter value:
Example output
```
  ...
  spec:
    clusterID: db93436d-7b05-42cc-b856-43e11ad2d31a
    upstream: '<update-server-url>' (1)
  ...
```
1 The <update-server-url> variable specifies the URL for the update server.

The default upstream is https://api.openshift.com/api/upgrades_info/v1/graph.
Click Save.