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

[Fiona Ebner <f.ebner@proxmox.com>]

Am 25.04.25 um 15:25 schrieb Daniel Kral:
> On 4/25/25 14:25, Fiona Ebner wrote:
>> Am 25.04.25 um 10:36 schrieb Daniel Kral:
>>> On 4/24/25 12:12, Fiona Ebner wrote:
>>> As suggested by @Lukas off-list, I'll also try to make the check
>>> selective, e.g. the user has made an infeasible change to the config
>>> manually by writing to the file and then wants to create another rule.
>>> Here it should ignore the infeasible rules (as they'll be dropped
>>> anyway) and only check if the added rule / changed rule is infeasible.
>>
>> How will you select the rule to drop? Applying the rules one-by-one to
>> find a first violation?
> 
> AFAICS we could use the same helpers to check whether the rules are
> feasible, and only check whether the added / updated ruleid is one that
> is causing these troubles. I guess this would be a reasonable option
> without duplicating code, but still check against the whole config.
> There's surely some optimization potential here, but then we would have
> a larger problem at reloading the rule configuration for the manager
> anyway. For the latter I could check for what size of a larger
> configuration this could become an actual bottleneck.
> 
> For either adding a rule or updating a rule, we would just make the
> change to the configuration in-memory and run the helper. Depending on
> the result, we'd store the config or error out to the API user.

ACK, I also don't think we need to worry too much about optimization
here yet.

>>> But as you said, it must not change the user's configuration in the end
>>> as that would be very confusing to the user.
>>
>> Okay, so dropping dynamically. I guess we could also disable such rules
>> explicitly/mark them as being in violation with other rules somehow:
>> Tri-state enabled/disabled/conflict status? Explicit field?
>>
>> Something like that would make such rules easily visible and have the
>> configuration better reflect the actual status.
>>
>> As discussed off-list now: we can try to re-enable conflicting rules
>> next time the rules are loaded.
> 
> Hm, there's three options now:
> 
> - Allowing conflicts over the create / update API and auto-resolving the
> conflicts as soon as we're able to (e.g. on the load / save where the
> rule becomes feasible again).
> 
> - Not allowing conflicts over the create / update API, but set the state
> to 'conflict' if manual changes (or other circumstances) made the rules
> be in conflict with one another.
> 
> - Having something like the SDN config, where there's a working
> configuration and a "draft" configuration that needs to be applied. So
> conflicts are allowed in drafts, but not in working configurations.
> 
> The SDN option seems too much for me here, but I just noticed some
> similarity.
> 
> I guess one of the first two makes more sense. If there's no arguments
> against this, I'd choose the second option as we can always allow
> intentional conflicts later if there's user demand or we see other
> reasons in that.

I do prefer the second option :)


_______________________________________________
pve-devel mailing list
pve-devel@lists.proxmox.com
https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel