Migrating from single node to three-node cluster

[oviano]

So I've been trying out Proxmox on an Intel NUC. I've got it all working nicely; I created 4 x VMs all on the one single node (call this Node1). Performance is better than I expected for a single node, which is good. The VMs all have hard disk sizes of 256GB so quite small.

Now I want to add two more nodes (identical NUC hardware, call these Node2 and Node3) and create a three-node cluster so I have redundancy and to maximise the performance of my VMs.

After reading bits and pieces from various sources, would the following be the correct approach?

1. Back up the VMs on the Node1 to my shared NFS NAS storage (actually I'm already doing this on a schedule)
2. Create Node2 and Node3 and create a two-node cluster from them
3. Restore the VMs to Node2/3
4. Remove the VMs from Node1
5. Add Node1 to the cluster
6. Move the VMs into their final positions using the cluster/migrate

I guess I don't need Step 3, but I guess I don't like having the VMs only exist on the shared storage for longer than absolutely necessary!

 

[janczmok]

Approach would be easy:
- On Node1 create a Cluster, and Node2 and Node3 joining the cluster

Tip: Dedicated Lan for Migration is always better, e.g. LAN1 is "outside" LAN for the normal VMs to speak to the world, and LAN2 is "sync-LAN" for server migration etc.

Once cluster created and you got those working together, just online migrate from Node1 to Node2 or Node3

 

[Chris]

Hi,
you can do this way easier. Just create a cluster from the already existing node with the VMs on it, install Proxmox VE on the other two node and join them to the cluster. The 2 new nodes will have to be empty (no VMs/CTs) to not run into conflicting VMIDs and the like. You can follow the steps outlined in the docs https://pve.proxmox.com/pve-docs/pve-admin-guide.html#chapter_pvecm

Of course you should have a tested backup of the VMs/CTs before starting with the procedue.

 

[oviano]

Hi,
you can do this way easier. Just create a cluster from the already existing node with the VMs on it, install Proxmox VE on the other two node and join them to the cluster. The 2 new nodes will have to be empty (no VMs/CTs) to not run into conflicting VMIDs and the like. You can follow the steps outlined in the docs https://pve.proxmox.com/pve-docs/pve-admin-guide.html#chapter_pvecm

Of course you should have a tested backup of the VMs/CTs before starting with the procedue.

Ah ok, thanks.

Could've sworn I read somewhere about not being able to join a node to a cluster if the node had VMs on it, maybe it was old or I misread.

 

[lordandy]

You can't add a node which has VMs running to a cluster - but if you only have 1 Node, just create the cluster on that one initially, and then join the other (empty) nodes to the cluster - this works and I just did it as well but I'm now stuck on some optimization with networking

 

[oviano]

You can't add a node which has VMs running to a cluster - but if you only have 1 Node, just create the cluster on that one initially, and then join the other (empty) nodes to the cluster - this works and I just did it as well but I'm now stuck on some optimization with networking

Brilliant, thank you.

Hope you sort your issue

 

[oviano]

Approach would be easy:
- On Node1 create a Cluster, and Node2 and Node3 joining the cluster

Tip: Dedicated Lan for Migration is always better, e.g. LAN1 is "outside" LAN for the normal VMs to speak to the world, and LAN2 is "sync-LAN" for server migration etc.

Once cluster created and you got those working together, just online migrate from Node1 to Node2 or Node3

Thank you. Yes, I have read about a dedicated LAN. At this stage I'm not going to do that, as I'm only really looking at the cluster as a way of handling a node breaking down and being able to migrate a VM from a backup to a different node; i.e. I'm not going in to HA/shared storage for the VMs etc, so I don't think the cluster traffic warrants the upgrades I would have to make to the NUCs.

Also, I'm trying to take things one step at a time, as I'm new to this. But maybe in future.