You can update, or upgrade, an {product-title} cluster. If your cluster contains Red Hat Enterprise Linux (RHEL) machines, you must perform more steps to update those machines.
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Have access to the cluster as a user with
adminprivileges. See Using RBAC to define and apply permissions. -
Have a recent etcd backup in case your upgrade fails and you must restore your cluster to a previous state.
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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.
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Important
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If you are running cluster monitoring with an attached PVC for Prometheus, you might experience OOM kills during cluster upgrade. When persistent storage is in use for Prometheus, Prometheus memory usage doubles during cluster upgrade and for several hours after upgrade is complete. To avoid the OOM kill issue, allow worker nodes with double the size of memory that was available prior to the upgrade. For example, if you are running monitoring on the minimum recommended nodes, which is 2 cores with 8 GB of RAM, increase memory to 16 GB. For more information, see BZ#1925061. |
modules/update-service-overview.adoc .Additional resources
You can use hooks to run Ansible tasks on the RHEL compute machines during the {product-title} update.