2.2. Prerequisites

Before you upgrade your cluster:

Review the OpenShift Container Platform 3.11 Release Notes. The release notes contain important notices about changes to OpenShift Container Platform and its function.
If you are completing a large-scale upgrade, which involves at least 10 worker nodes and thousands of projects and pods, review Special considerations for large-scale upgrades to prevent upgrade failures.
If you are completing a disconnected cluster update, you must update your image registry with new image versions or the cluster update will fail. For example, when updating from 3.11.153 to 3.11.157, make sure the v3.11.157 image tags are present.
Upgrade the cluster to the latest asynchronous release of version 3.10. If your cluster is at a version earlier than 3.10, you must first upgrade incrementally. For example, upgrade from 3.7 to 3.9 (the 3.8 version was skipped), and then from 3.9 to 3.10.
Run the Environment health checks to verify the cluster’s health. In this process, you confirm that the nodes are in the Ready state and running the expected starting version and that there are no diagnostic errors or warnings.
Ensure that your cluster meets the current prerequisites. If it does not, your upgrade might fail.
The day before the upgrade, validate OpenShift Container Platform storage migration to ensure potential issues are resolved before the outage window:
```
$ oc adm migrate storage --include=* --loglevel=2 --confirm --config /etc/origin/master/admin.kubeconfig
```