Reintegration of an isolated RKE cluster

Rancher
1

Hi there.

Introduction:

We have a problem with one of our (RKE) Clusters, which was created by using Rancher “Add Cluster → Existing Nodes”.

Some months ago, due to a combination of unfortunate circumstances, the Rancher + the target cluster got unresponsive.
After setting up a new Rancher cluster, the isolated target cluster got reintegrated as external cluster.
This works quite nice, but now some important features are not possible anymore, like:

  • Updating the Kubernetes version
  • Adding new nodes

The question:

  • Is is somehow possible to reintegrate the target cluster as RKE-Cluster to make it fully manageable (without having to set it up again)?

If this is not possible:

  1. do you have advice for the best way to proceed? Do you know any tool to fetch
    all required manifests from the cluster to re-use it on a new cluster?
  2. how can I handle updates, adding nodes etc. via the target cluster commandline?

Thanks in advance.

Technical Note: Rancher version is 2.5.2

Greetings