Updating clusters overview

With update channels, you can choose an update strategy. Update channels are specific to a minor version of OKD. Update channels only control release selection and do not impact the version of the cluster that you install. The openshift-install binary file for a specific version of the OKD always installs that minor version.

OKD 4.16 offers the following update channel:

Updating a cluster using the web console: You can update an OKD 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.

Updating a cluster using the CLI: You can update an OKD cluster within a minor version by using the OpenShift CLI (oc). The following steps update a cluster within a minor version. You can use the same instructions for updating a cluster between minor versions.

Performing a canary rollout update: By controlling the rollout of an update to the worker nodes, you can ensure that mission-critical applications stay available during the whole update, even if the update process causes your applications to fail. Depending on your organizational needs, you might want to update a small subset of worker nodes, evaluate cluster and workload health over a period of time, and then update the remaining nodes. This is referred to as a canary update. Alternatively, you might also want to fit worker node updates, which often requires a host reboot, into smaller defined maintenance windows when it is not possible to take a large maintenance window to update the entire cluster at one time. You can perform the following procedures:

About cluster updates in a disconnected environment: If your mirror host cannot access both the internet and the cluster, you can mirror the images to a file system that is disconnected from that environment. You can then bring that host or removable media across that gap. If the local container registry and the cluster are connected to the mirror host of a registry, you can directly push the release images to the local registry.

Updating hardware on vSphere: You must ensure that your nodes running in vSphere are running on the hardware version supported by OpenShift Container Platform. Currently, hardware version 15 or later is supported for vSphere virtual machines in a cluster. For more information, see the following:

Updating hosted control planes: On hosted control planes for OKD, updates are decoupled between the control plane and the nodes. Your service cluster provider, which is the user that hosts the cluster control planes, can manage the updates as needed. The hosted cluster handles control plane updates, and node pools handle node updates. For more information, see the following information: