Proxmox VE4: 2 nodes HA failover possbile (with a trick?)

R

Ruben Waitz

Member
Aug 6, 2012
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Hi,

I've extensively tested PVE4 in HA mode with DRBD9 on a 3 nodes cluster, based on the instructions at http://pve.proxmox.com/wiki/High_Availability_Cluster_4.x
The fail-over mechanism works nice!

Now I need to setup a PVE4 HA/DRBD9 cluster with 2 nodes. I know the wiki page (mentioned above) requires 3 nodes, but is it possible to do it with 2 nodes somehow? My current setup seems to work fine, but lacks to do the actual fail-over. I found this article http://pve.proxmox.com/wiki/Two-Node_High_Availability_Cluster, but that's for the old PVE version.

Thanks in advance.

Best Regards,
Ruben
 
If you want HA failover, you *must* have at least three nodes. The third node can be a tiny box that does never run any VMs.
 
Hi vkhera,

Thank you for answering.
I assume this tiny box is for the quorum/pmxcfs.

Do you think the HD of this tiny box could also be small?
To put it simply, when I create the DRBD9 configuration, does it matter the 'tiny box' node has a small HD? (Furthermore in the PVE-UI I can configure fail-over only the other nodes).

Thank you in advance for answering!

Ruben
 
Ruben Waitz said:
Hi vkhera,

Thank you for answering.
I assume this tiny box is for the quorum/pmxcfs.

Do you think the HD of this tiny box could also be small?
To put it simply, when I create the DRBD9 configuration, does it matter the 'tiny box' node has a small HD? (Furthermore in the PVE-UI I can configure fail-over only the other nodes).

Thank you in advance for answering!

Ruben
Click to expand...

Yes the third node can simply provide a vote to achieve quorum. You can setup groups and failover domains to ensure the VM only runs on specific nodes. There should be no issue with the 3rd node having a small harddrive.
 
I was thinking about this and how PVE4 does not have support for a quorum disk. I was about to set up a third tiny node for quorum as the PVE dev's suggest, but then I realized that now I have to go buy another license key since all nodes on my cluster must be licensed to the same level, so that adds another 220EUR annually just for that.

I would request that there be a cheap or free license for this use case.
 
vkhera said:
I was thinking about this and how PVE4 does not have support for a quorum disk. I was about to set up a third tiny node for quorum as the PVE dev's suggest, but then I realized that now I have to go buy another license key since all nodes on my cluster must be licensed to the same level, so that adds another 220EUR annually just for that.

I would request that there be a cheap or free license for this use case.
Click to expand...

If your that concerned about it, use the free repo's for the 3rd node.
 
hi

may be rebuilding a minimal set of proxmox cluster related package for rasberry is a good alternative :-)

A+
 
adamb said:
If your that concerned about it, use the free repo's for the 3rd node.
Click to expand...

From the subscription purchase page: "In a Proxmox VE Cluster you need to have the same subscription level for all your servers." so your idea doesn't work, as I pointed out originally.
 
demoze said:
may be rebuilding a minimal set of proxmox cluster related package for rasberry is a good alternative :-)
Click to expand...

The proxmox developers indicated they did not have the inclination to do this. I do not know what minimal set of packages would be necessary for this to build it myself.
 
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