You can update a OKD cluster with a single operation by using the web console or the OpenShift CLI (oc) with OKD 4.
About the OpenShift Update Service: For clusters with internet accessibility, Red Hat provides over-the-air updates through an OKD update service as a hosted service located behind public APIs.
Upgrade channels and releases: Upgrade channels allow you to choose an upgrade strategy. Upgrade channels are connected to a minor version of OKD. Upgrade channels control only release selection and do not impact the version of the cluster that you install; the openshift-install binary file for a specific version of OKD always installs that version. For more information, see the following:
Preparing to perform an EUS-to-EUS update: Due to fundamental Kubernetes design, all OKD updates between minor versions must be serialized. You must update from OKD 4.8 to 4.9, and then to 4.10. You cannot update from OKD 4.8 to 4.10 directly. However, if you want to update between two Extended Update Support (EUS) versions, you can do so by incurring only a single reboot of non-master hosts. For more information, see the following item:
Updating a cluster within a minor version using the web console: You can update an OKD cluster by using the web console. You can the update a cluster between minor versions. For more information, see the following items:
Updating a cluster within a minor version using the CLI: You can update an OKD cluster by using the
oc. You can the update a cluster between minor versions. For more information, see the following actions:
Performing a canary rollout update: By controlling 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 actions:
Updating a cluster that includes Fedora compute machines: You can update an OKD cluster. If your cluster contains Fedora machines, you must update those machines. You can perform the following actions:
Updating a restricted network cluster: A restricted network environment is one in which your cluster nodes cannot access the internet. You can update a restricted network OKD cluster by using the
oc. You can also update a restricted network OKD cluster by using the OpenShift Update Service. For more information, see the following items:
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 13 or later is supported for vSphere virtual machines in a cluster. For more information, see the following information:
Using hardware version 13 for your cluster nodes running on vSphere is now deprecated. This version is still fully supported, but support will be removed in a future version of OKD. Hardware version 15 is now the default for vSphere virtual machines in OKD.