Joining a cluster with already created guests VM

Gryd3 said:
I have a work-around that *might* work for you, but has not been thoroughly tested.
There is a firm requirement however that there must not be any conflicts with the guest ID, or the node name.

On node1 (with guests)
Create a new cluster or get join information.

On node2 (with guests)
scp -r /etc/pve/nodes/* to node1:/etc/pve/nodes
rm -r /etc/pve/nodes/*
Join cluster.

Please realize there is potential for things to go sideways!
I've done this to re-assemble a cluster I've recently had to pick apart, and can't provide any details on long-term issues or risk.
I cannot suggest this work-around at the moment for nodes that have never been in a cluster with each other.
I've done this with online VMs! and they remain operational through the process. The join cluster process will overwrite the contents of /etc/pve/nodes with copies from the cluster... so copying your new node directory to the cluster with scp will indirectly restore it on cluster join.

Good luck.
Click to expand...
Thanks, it worked just fine!
I also backed up storage.cfg on joining node and appended the contents to the cluster storage.cfg.
 
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Golden solution

If there are conflicting ID's you can temporarily rename files in /etc/pve/nodes/<node-name>/qemu-server/[ID].conf

Coming from ESXI this limitation is a bit strange. There are many many use cases where a user would need to join a node with existing guests. Also like another user said, in a sane world pve would be tracking these with GUIDs in the background and the VM ID number would be user facing only
 
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Hi folks,

I tried the SCP way like above up comments said it but didn't work me. so I tried this on my own and it worked for me!

on the new node take a backup of /etc/pve/nodes/YOURNEWNODENAME/qemu-server and delete all the files in it and try to join the server once done restore the file to original location, it worked for me!

1. NewNode: cp -rpf /etc/pve/nodes/YOURNEWNODENAME/qemu-server /root/
2. NewNode: rm -rf /etc/pve/nodes/YOURNEWNODENAME/qemu-server/*
3. OldNode: get the "Join Information" from your main
4. NewNode: click on "Join Cluster" and add the info copied earlier and join the cluster
5. NewNode: cp -rpf /root/qemu-server /etc/pve/nodes/YOURNEWNODENAME/

and you are done! just Make sure you have no conflicting VM / LXC IDs.

Good Luck!
 
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Thejeswar_Reddy said:
Hi folks,

I tried the SCP way like above up comments said it but didn't work me. so I tried this on my own and it worked for me!

on the new node take a backup of /etc/pve/nodes/YOURNEWNODENAME/qemu-server and delete all the files in it and try to join the server once done restore the file to original location, it worked for me!

1. NewNode: cp -rpf /etc/pve/nodes/YOURNEWNODENAME/qemu-server /root/
2. NewNode: rm -rf /etc/pve/nodes/YOURNEWNODENAME/qemu-server/*
3. OldNode: get the "Join Information" from your main
4. NewNode: click on "Join Cluster" and add the info copied earlier and join the cluster
5. NewNode: cp -rpf /root/qemu-server /etc/pve/nodes/YOURNEWNODENAME/

and you are done! just Make sure you have no conflicting VM / LXC IDs.

Good Luck!
Click to expand...
This is what I have in mind
Will try with a small node (2vm and they are backed up)
 
Disco said:
Hello, how about this https://www.youtube.com/watch?v=4Z3wS6nMUtQ
Just move conf file of VMs temporarily. I consider this method just genious, until someone proves other.
Click to expand...
Thanks for the suggestion, I did this and it worked. In my case I only had 1 VM)
For those that don't want to watch the (too) long video (or if the video is gone), here are the steps:
  1. Shutdown any VMs (or containers)
  2. Take note of any VM mappings
  3. Move the VM config (/etc/pve/nodes/$HOSTNAME/qemu-server) to a different location (can even be on the same host: I just used /root/)
  4. Join the cluster normally via the GUI (still had the usuall disconnection issues, and I did the P2P SSH to accept the keys)
  5. Restore the VM config
  6. Restore the mappings
  7. Start the VM
I had some trouble where I had a mapped USB drive to the VM which was no visible in the USB mappings anymore until I restarted the node.

DISCLAIMER/WARNING:
This process appear to overwrite whatever you had in /etc/pve/storage.cfg
So be sure to backup that file and then manually update as needed!
 
Gryd3 said:
I have a work-around that *might* work for you, but has not been thoroughly tested.
There is a firm requirement however that there must not be any conflicts with the guest ID, or the node name.

On node1 (with guests)
Create a new cluster or get join information.

On node2 (with guests)
scp -r /etc/pve/nodes/* to node1:/etc/pve/nodes
rm -r /etc/pve/nodes/*
Join cluster.

Please realize there is potential for things to go sideways!
I've done this to re-assemble a cluster I've recently had to pick apart, and can't provide any details on long-term issues or risk.
I cannot suggest this work-around at the moment for nodes that have never been in a cluster with each other.
I've done this with online VMs! and they remain operational through the process. The join cluster process will overwrite the contents of /etc/pve/nodes with copies from the cluster... so copying your new node directory to the cluster with scp will indirectly restore it on cluster join.

Good luck.
Click to expand...
Thank you!
Worked flawless here.
PVE 8.4.1
 
Gryd3 said:
On node1 (with guests)
Create a new cluster or get join information.

On node2 (with guests)
scp -r /etc/pve/nodes/* to node1:/etc/pve/nodes
rm -r /etc/pve/nodes/*
Join cluster.
Click to expand...
Thanks man, this works like a charm, using origin node on proxmox 7.x and destination node on proxmox 8.x,
 
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