Hi all - we just imported the existing cluster into the rancher; However, after doing that, we are not able to re-scale the cluster anymore; When editing Config of the Imported cluster, only Annotations and and Member roles are visible. Nothing else. Is there still something we have to do after importing?

Importing a cluster into Rancher doesn't allow you to scale the nodes of that cluster. Additionally, you can manage the Kubernetes version of the cluster unless the imported cluster is K3s or RKE2.

Thank you so much for your feedback @big-hydrogen-97240. The Cluster we imported was created before in Rancher, but we had to completely re-create the rancher instance.

If you had backups of your previous Rancher instance via

rancher-backup

then you can restore the previous Rancher instance to your new one. That would bring everything back.

sadly, we do not have instances/backups

Then there is likely some hacky way to get it working again, but you are probably better off recreating the cluster from the new Rancher instance.

shouldn’t this somehow be possible with this steps? https://ranchermanager.docs.rancher.com/v2.0-v2.4/how-to-guides/new-user-guides/kubernetes-clusters-in-rancher-setup/import-existing-clusters

No. As I said above, importing an existing cluster doesn't give you the ability to scale the cluster. For example, importing an existing cluster won't tell the Rancher server where the cluster is provisioned, which keys are needed to create new nodes, etc.