[pve-devel] [RFC cluster/ha-manager 00/16] HA colocation rules

[Fabian Grünbichler]

On April 1, 2025 11:39 am, Daniel Kral wrote:
> On 4/1/25 03:50, DERUMIER, Alexandre wrote:
>> Small feature request from students && customers:  they are a lot
>> asking to be able to use vm tags in the colocation/affinity
> 
> Good idea! We were thinking about this too and I forgot to add it to the 
> list, thanks for bringing it up again!
> 
> Yes, the idea would be to make pools and tags available as selectors for 
> rules here, so that the changes can be made rather dynamic by just 
> adding a tag to a service.
> 
> The only thing we have to consider here is that HA rules have some 
> verification phase and invalid rules will be dropped or modified to make 
> them applicable. Also these external changes must be identified somehow 
> in the HA stack, as I want to keep the amount of runs through the 
> verification code to a minimum, i.e. only when the configuration is 
> changed by the user. But that will be a discussion for another series ;).

something to also consider is HA permissions:

https://bugzilla.proxmox.com/show_bug.cgi?id=4597

e.g., who is supposed to define (affinity or other) rules, who sees
them, what if there are conflicts, ..

what about conflicting requests? let's say we have a set of 5 VMs that
should run on the same node, but one is requested to be migrated to node
A, and a second one to node B? if a user doesn't see the rules for lack
of privileges this could get rather confusing behaviour wise in the end?

what about things like VMs X and Y needing to run together, but Z not
being allowed to run together with Y, and user A that only "sees" X
requesting X to be migrated to the node where Z is currently running?