Merge 2 servers with guests in a cluster

[jinjer]

Hi all.

I have a simple question regarding (manual) cluster construction.

I need to join a remote server running proxmox 1.5 to a server in my office without recreating/reinstalling the remote server (the local proxmox is running 1.6 atm).

I just need the remote server to be controlled from the local server. I don't need drbd/sharing and migration.

There's no possibility at the moment to touch the remote server to which I only have ssh access (no keyboard/video/mouse, and I'd like to avoid reboots as much as possible).

The cluster howto explicitly states that the new server that is joined must have no running guests.

Any hints ?

thank you,
jinjer

 

[tom]

All nodes should be in the same network, so your scenario is not really supported.

Basically, you need to make sure that both nodes are running the same version and if you have VM´s on the node, you need to make sure that you do not have conflicting/identical VMID´s - those needs to be unique in a cluster.

 

[jinjer]

Tom, this was a quick answer. Thank you.

I'm concerned about the existing configurations on the "slave" server when joining a master. Are they migrated during the join, or is the master continuously polling the slave for changes?

So, the issues seem to be:

1. VMID must be unique (this is easy to obtain).
2. Proxmox version must match
3. The network must be "local"

Regarding issue #2, I'm wondering if there's an api which changes between 1.5 and 1.6 or if the master just logins to the slave via SSH and issues commands. I will setup a 1.5/1.6 setup for testing purposes in my office, so I'm looking for general tips here.

Technically, the remote server could be accessed in the "local net" via vpn links. However, my (uneducated) guess would be that local network is necessary for migration/drbd and possibly iscsi/shared storage. As I'll obviously not attempt such things between data centers, are there other issues that are worth pointing (out of your head)?

jinjer.

 

[tom]

mixing 1.5/1.6 should work but we do never support or test such scenarios. using a VPN will work now but not with the upcoming Proxmox VE 2.x series (new cluster communication)

 

[jinjer]

Ok, I'll post my findings regarding the 1.5/1.6 merge. I'm starting to dig a little in the perl code and like what I see (so far

I think proxmox is a very nice piece of software and with little effort could grow in something really useful for more complex scenarios (multiple data centers, well defined api to help with mixing different levels of bare-metal installations, cold-migration across data centers etc).

What I like most is that it parses existing configuration files instead of relying on a database.

 

[tom]

Ok, I'll post my findings regarding the 1.5/1.6 merge. I'm starting to dig a little in the perl code and like what I see (so far

I think proxmox is a very nice piece of software and with little effort could grow in something really useful for more complex scenarios (multiple data centers, well defined api to help with mixing different levels of bare-metal installations, cold-migration across data centers etc).

API will come for 2.x. very nice.

What I like most is that it parses existing configuration files instead of relying on a database.

yes, we try to keep VM config files "human readable". 99,9 % of users do not understand complex xml config files - just adding a lot of complexity with no or maybe just little benefit.

 

[jinjer]

I tried a cluster with 1.5 master and 1.6 slave and it works. I guess the other way around will be fine too. After sync, the machines from the slave are visible in the master too, so the only possible problem is to make sure the IDs are different.

There's a little bug I found: The master I used is an atom D510 which is x64 enabled but has no VT. The slave I used is fully VT capable. The proxmox interface on the master does not allow creation of KVM guests on the slave, even if it's capable of doing so. It must be a simple fix somewhere...

jinjer.

 

[tom]

...
There's a little bug I found: The master I used is an atom D510 which is x64 enabled but has no VT. The slave I used is fully VT capable. The proxmox interface on the master does not allow creation of KVM guests on the slave, even if it's capable of doing so. It must be a simple fix somewhere...

jinjer.

I consider this not as a design issue. I suggest you promote the slave to the master.

 

[jinjer]

I consider this not as a design issue. I suggest you promote the slave to the master.

Well, there will be a problem on the other side, creating kvm guest on non-kvm enabled host would become possible. Ideally, create.htm should consider the currently selected slave and get it's processor caps (via ssh).