On Wed, 31 Jan 2024 18:23:40 +0100 lejeczek via Users <users@clusterlabs.org> wrote:
> On 31/01/2024 17:13, Jehan-Guillaume de Rorthais wrote: > > On Wed, 31 Jan 2024 16:37:21 +0100 > > lejeczek via Users <users@clusterlabs.org> wrote: > > > >> > >> On 31/01/2024 16:06, Jehan-Guillaume de Rorthais wrote: > >>> On Wed, 31 Jan 2024 16:02:12 +0100 > >>> lejeczek via Users <users@clusterlabs.org> wrote: > >>> > >>>> On 29/01/2024 17:22, Ken Gaillot wrote: > >>>>> On Fri, 2024-01-26 at 13:55 +0100, lejeczek via Users wrote: > >>>>>> Hi guys. > >>>>>> > >>>>>> Is it possible to trigger some... action - I'm thinking specifically > >>>>>> at shutdown/start. > >>>>>> If not within the cluster then - if you do that - perhaps outside. > >>>>>> I would like to create/remove constraints, when cluster starts & > >>>>>> stops, respectively. > >>>>>> > >>>>>> many thanks, L. > >>>>>> > >>>>> You could use node status alerts for that, but it's risky for alert > >>>>> agents to change the configuration (since that may result in more > >>>>> alerts and potentially some sort of infinite loop). > >>>>> > >>>>> Pacemaker has no concept of a full cluster start/stop, only node > >>>>> start/stop. You could approximate that by checking whether the node > >>>>> receiving the alert is the only active node. > >>>>> > >>>>> Another possibility would be to write a resource agent that does what > >>>>> you want and order everything else after it. However it's even more > >>>>> risky for a resource agent to modify the configuration. > >>>>> > >>>>> Finally you could write a systemd unit to do what you want and order it > >>>>> after pacemaker. > >>>>> > >>>>> What's wrong with leaving the constraints permanently configured? > >>>> yes, that would be for a node start/stop > >>>> I struggle with using constraints to move pgsql (PAF) master > >>>> onto a given node - seems that co/locating paf's master > >>>> results in troubles (replication brakes) at/after node > >>>> shutdown/reboot (not always, but way too often) > >>> What? What's wrong with colocating PAF's masters exactly? How does it > >>> brake any replication? What's these constraints you are dealing with? > >>> > >>> Could you share your configuration? > >> Constraints beyond/above of what is required by PAF agent > >> itself, say... > >> you have multiple pgSQL cluster with PAF - thus multiple > >> (separate, for each pgSQL cluster) masters and you want to > >> spread/balance those across HA cluster > >> (or in other words - avoid having more that 1 pgsql master > >> per HA node) > > ok > > > >> These below, I've tried, those move the master onto chosen > >> node but.. then the issues I mentioned. > > You just mentioned it breaks the replication, but there so little > > information about your architecture and configuration, it's impossible to > > imagine how this could break the replication. > > > > Could you add details about the issues ? > > > >> -> $ pcs constraint location PGSQL-PAF-5438-clone prefers > >> ubusrv1=1002 > >> or > >> -> $ pcs constraint colocation set PGSQL-PAF-5435-clone > >> PGSQL-PAF-5434-clone PGSQL-PAF-5433-clone role=Master > >> require-all=false setoptions score=-1000 > > I suppose "collocation" constraint is the way to go, not the "location" > > one. > This should be easy to replicate, 3 x VMs, Ubuntu 22.04 in > my case No, this is not easy to replicate. I have no idea how you setup your PostgreSQL replication, neither I have your full pacemaker configuration. Please provide either detailed setupS and/or ansible and/or terraform and/or vagrant, then a detailed scenario showing how it breaks. This is how you can help and motivate devs to reproduce your issue and work on it. I will not try to poke around for hours until I find an issue that might not even be the same than yours. _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
