On 01/02/2024 15:02, Jehan-Guillaume de Rorthais wrote:
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.
How about you start with the basics - strange inclination to
complicate things when they are not, I hear from you -
that's what I did while "stumbled" upon these "issues"
How about just:
a) do vanilla-default pgSQL in Ubuntu (or perhaps any other
OS of your choice), I use _pg_createcluster_
b) follow PAF official guide (a single PAF resource should
suffice)
Have a healthy pgSQL cluster, OS _reboot_ nodes - play with
that, all should be ok, moving around/electing master should
work a ok.
Then... add, play with "additional" co/location constraints,
then OS reboots,- things should begin braking.
I have 3-node HA cluster & 3-node PAF resource = 1 master +
2 slaves.
Only thing I deliberately set, to alleviate pgsql
replication was _wal_keep_size_ - I increased that, but this
is subjective.
It's fine with me if you don't feel like doing this.
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