[SOLVED] Migrating to a new server

[sshaikh]

I am trying to figure out a strategy to move my existing PVE installation to a new server. The new host will have new disks etc, so data will need to be migrated (as opposed to just physically moving the disk). I am also taking this opportunity to install Proxmox fresh. Quite significantly, I wish to keep the host/node name for the new host.

My initial plan was to rename the existing node, set up the new host, and then migrate the VMs over. However I have since found that renaming nodes with VMs is non trivial.

Is it possible to:

1. Update the DNS entry of the existing host
2. Install the new node with the same name and use the old DNS name (and have these exist on the network at the same time)
3. Migrate VMs using DNS names (ie with no visibility of the proxmox node names)

If not, does anyone have any tips on how to achieve this?

 

[emunt6]

Hi!

It is depends on your setup:
Option 1:
-You adding the new server to the existing cluster, migrate/move VMs to new server, then delete the old server from the cluster.

Option 2:
-Clone the Proxmox OS disk into the new server, adjust the parameters, done.

 

[fabian]

you can also use remote migration or backup+restore if you don't want to or cannot cluster the old and new node

 

[sshaikh]

I naively assumed nodes in a cluster have to have unique names. Is this not the case?

The complication here is a) wanting to keep (or reuse) the node name and b) have both old and new nodes up as I migrate the (offline) VMs.

 

[UdoB]

I naively assumed nodes in a cluster have to have unique names. Is this not the case?

No. The names do not matter; you can name three nodes frodo, enterprise and pve1. The important thing is that all nodes need to know the names in a consistent manner. Either you have setup full-blown (and redundant) DNS or you need to maintain /etc/hosts. The file should contain the same information on all nodes.

On each node ~# ping -c1 frodo; ping -c1 enterprise; ping -c1 pve1 needs to work flawlessly and give consistent information.

At the end ~# for H in frodo enterprise pve1; do ssh root@$H hostname ; done will work on all nodes identically.

Good luck

 

[sshaikh]

Ok I suspect I'm being dim or unclear (or probably both).

My current node is called "frodo".

I want to build a new node with new hardware, migrate my VMs over and decommission the old node.

There will be a period where both nodes will be running as machines are migrated.

Eventually I want this new node to be called "frodo".

Given nodes cannot be renamed (easily) while they contain VMs, how would I do this?

My current plan is to backup-delete-rename-restore the current node to "frodo-legacy" and carry on. I'm asking if there's another way that I'm missing.

 

[UdoB]

Given nodes cannot be renamed (easily) while they contain VMs, how would I do this?

Does this: https://pve.proxmox.com/wiki/Renaming_a_PVE_node help? For me this looks easy enough.

I am not sure if you run a cluster or not. Experiments with a cluster are always somewhat risky. If you really only have a single node there should be no problem.

Good luck

 

[sshaikh]

It doesn't I'm afraid:

Proxmox VE uses the hostname as a nodes name, so changing it works similar to changing the host name. This must be done on a empty node.

It's exactly the empty node requirement that makes this non trivial. Cluster vs standalone doesn't seem to be relevant.

Looks like deleting and restoring the VMs is the best way forward. Do I have to backup the storage too or will that survive a rename?

 

[sshaikh]

I threw caution to the wind and used the following thread to rename the node:

https://forum.proxmox.com/threads/proxmox-node-name-change.14327/

Very hacky and the cluster is no more but since it's temporary it'll work for in this case.