Cluster with 3 nodes and failover nic

[mlc42]

i, try to build a cluster with 2 identical nodes (with storage) and one only for quorum.

The 2 nodes with storage have 2 nics, one 2.5 GB (should later be used for replication)
and one 1 GB nic.

The 3 node has only one 1 GB nic.

When building the cluster at the first and second node i use one nic for primary work and the
other as failover.
After that it is impossible to add the 3 node (with one nic) to the cluster.
If i only use one nic at all three nodes it works, but i have no failover for the important nodes one and two.

Do i need to add a second nic to the third node and why ?


Best regards
Martin

 

[dylanw]

Rather than trying to create a 3 node cluster, setting up a 2 node cluster with an external qdevice [1] may be more appropriate for your setup.

[1] https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_corosync_external_vote_support

 

[mlc42]

I´ve done this with a raspi4 as third quorum device, works fine.
But unfortunately i found no way to get drbd/linstor running
in that configuration. I think i had to build the drdb/linstor packages
for raspi to get it running. At the moment i use a pc for the third node.
With one 1 GB nic my Cluster runs in acceptable speed.

Best regards
Martin

 

[dylanw]

Sorry, I am not very familiar with drbd/linstor, is it required to run on the three nodes, even if one is just a qdevice? Would pve's storage replication [1] functionality be of any help as an alternative?

[1] https://pve.proxmox.com/pve-docs/pve-admin-guide.html#chapter_pvesr

 

[mlc42]

Years before i build a 2 node cluster with proxmox/drbd and powerswitch fencing.
It works until now without heavy problems.
Trying to build a new cluster with proxmox 6.4, i read that i can use
ZFS or CEPH nor more drbd integration. Ceph consumes a lot of hardware 3 identical nodes..
ZFS is only async replication. So in case of a failure of one node there will be a data loss since
the last replication. Because i cannot know what the vm´s are doing at this point it is not
very realiable. Linstor has a plugin for proxmox so i give it a try. They use there on quorum
so i must have a third (diskless) node. It would be fine to do this with raspberry. May be i found
out how. I know that some wrote not to use a raspi for that, but it has some advantages.
Easy to handle, very low power consumption and cheap.
In case of a failure i took another raspi, plugin a sdcard copy and my cluster will be ready again.
I´ve man raspis in industriell environment and privat use (kodi media center..) The all work very well
since years.

Best regards
Martin