What can be expected during a Rancher Hosted Prime upgrade?

There is minimal impact or disruption during a Rancher Hosted Prime upgrade. During the one-hour maintenance window you can expect a brief (usually 1-2 minutes) when your Rancher control plane UI/API is inaccessible. This does not impact the workloads on your managed downstream clusters, only your ability to make changes to these clusters. Immediately following the Rancher control plane upgrade, the cluster and node agents running in your managed downstream clusters will be upgraded and restarted. This also only takes a few minutes (unless you have very large clusters or very poor network speeds) and during this time Rancher will be unable to manage the cluster, but again the workloads running on the clusters should operate normally.