[ClusterLabs] qdevice network redundancy

[Jan Friesse]

Him
you mostly answered all your questions yourself correctly :) Only reason 
why there is no multiple links supported (yet) is really it is not 
implemented - it's one of todo 
(https://github.com/corosync/corosync-qdevice/issues/23). Also you are 
right, it is less reliable than having full third node, but it can be 
used by multiple clusters (full third node cannot be used that way). 
Also if qnetd is outside cluster network (= closer to customer of 
service provided by cluster) it can be used as decision maker what 
cluster partition is "better" (reachable by customer). In short, having 
just one cluster using qnetd inside cluster network is perfectly valid 
and possible use-case, but it's not really what qnetd primary purpose is 
(multiple, mostly 2-node, clusters, qnetd running on 3rd site).

Regards
   Honza


On 01/10/2025 05:06, Paul B. Henson via Users wrote:
> Hmm, I dug around the source code a bit after sending my first message.
> The proxmox documentation says to use an IP address when adding a
> qdevice:
> 
> https://www.proxmox.com/images/download/pve/docs/pve-admin-guide-9.0.pdf
> 
> 	"pvecm qdevice setup <QDEVICE-IP>"
> 
> The qdevice only supports a single "Host" option, but it seems if you
> specify an actual hostname and not an IP address it tries all of the IP
> addresses associated with that hostname when connecting, and if a
> connection fails, it tries them all again?
> 
> So it appears you can use a qdevice with redundancy across multiple
> network links and different subnets, but only if you configure it with a
> hostname that resolves to multiple IP addresses as opposed to
> configuring with a single IP address?
> 
> I don't think I'd want to involve dns in cluster config, but I suppose
> adding a qdevice name with multiple IP addresses to the hosts file on
> each node would work.
> 
> I'll have to test this...
> 
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