Reinstalling a Proxmox 7.4 node using backed-up files vs deleting and adding it back

jsabater

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Oct 25, 2021
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Palma, Mallorca, Spain
Hey everyone!

So I have a 7-node cluster of PVE 7.4 and I need to reinstall one of the nodes because I did not REDACTED when installing it. I would like to keep the same IP address and hostname. The node is already empty (i.e., all LXCs and VMs have already been migrated to another node) and HA is not being used.

Anyway, I've been reading about it and I seem to have two options.

Reinstall in-place

So this would mean not deleting the node from the cluster, reinstalling, configuring and bringing back the old configuration from backup. Steps:

1. Stop pve-cluster.service.
2. Stop corosync.service.
3. Stop everything that begins with pve and ends in .service?
4. Back up /etc/pve/ and /etc/corosync/.
5. Back up /root/.ssh/id*.
6. Back up something else?
7. Shut down the node.
8. Boot it up using Hetzner's rescue distro, and launch the installation process of Debian 11.
9. Install Proxmox on top of the existing Debian.
10. Stop pve-cluster.service and corosync.service.
11. Stop everything that begins with pve and ends in .service?
12. Overwrite the existing installation inside /etc/pve/ and /etc/corosync/ with the backup data.
13. Overwrite the existing root user SSH keys with the back-up.
14. Start pve-cluster.service and corosync.service, or just reboot?
15. Enjoy Proxmox. :)

Delete, install, re-add

So this would mean deleting the node from the cluster, reinstalling, configuring, and joining the cluster again. Steps:

1. Shut down the node proxmox5
2. From proxmox1, delete the node using pvecm delnode proxmox5. Make sure the SSH keys are gone, as well as anything proxmox5-like inside /etc/pve/.
3. Boot it up using Hetzner's rescue distro, and launch the installation process of Debian 11.
4. Install Proxmox on top of the existing Debian.
5. Configure the OS and everything else to my liking.
6. Join the cluster again.
7. Enjoy Proxmox. :)


Would anyone be so kind as to provide feedback upon the following questions?

1. Am I missing something in any of the steps above mentioned?
2. Is there any significant advantage (or less risk involved) in doing one or the other? I really don't mind doing either, but I'd like to know the pros and cons beforehand.

P.S. For some reason, I have the feeling (call it intutition) that the safest best is to remove the node, then add it again :rolleyes:

Thanks.

References:

* https://pve.proxmox.com/wiki/Cluster_Manager#_remove_a_cluster_node
* https://forum.proxmox.com/threads/reinstall-node-in-cluster.64281/
* https://forum.proxmox.com/threads/reinstall-node-in-cluster.88660/
* https://forum.proxmox.com/threads/reinstalling-a-node-within-a-cluster.50517/
 
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So I have a 7-node cluster of PVE 7.4 and I need to reinstall one of the nodes because I did not REDACTED when installing it. I would like to keep the same IP address and hostname.
I think the manual warns about reusing the same hostname and/or IP address, after you removed it from the cluster, on a new node. It will probably introduce more issues.
 
I think the manual warns about reusing the same hostname and/or IP address, after you removed it from the cluster, on a new node. It will probably introduce more issues.
I have read on the forums that it is convenient (necessary?) not to have HA in use, albeit I don't really know why, as I have not found anything on the official documentation regarding this.

What the documentation warns about is not to have replication on, but I am not sure why, as the node would be empty of VMs and LXCs prior to deletion, so no sync jobs would be active on that node. Not that I am using replication anyway.
 
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