[ClusterLabs] node1 and node2 communication time question

[Klaus Wenninger]

On Wed, Aug 10, 2022 at 3:49 AM 권오성 <kwonos.kau at gmail.com> wrote:
>
> Thank you for your reply.
> Then, can I think of it as being able to adjust the time by changing the token in /etc/corosync/corosync.conf?

That would basically be the time after which a non responsive
node in a cluster  would be declared dead and drop out of
the cluster.
But be careful when you set that time too low as your node
might drop out of the cluster because of a hickup in the
network or because load might prevent corosync from
being scheduled.
Then think of what it really means that a node isn't reachable
via network. It doesn't necessarily mean it is totally dead and
doesn't interfere with anything anymore or might come back
a second later.
With this uncertainty recovering a service on another node
is risky.
And this is where fencing kicks in to assure that this potentially
dead node is dead for sure before you proceed recovering
services from it.

> And the site I searched and found was explaining to disable fencing.
> If so, could you introduce me to a site or blog that explains by activating fencing?
> I am a college student studying about ha.
> I first learned about the concept of ha, and I don't know how to set it up or what options to change.
> And I am using a translator because I am not good at English, but I do not understand how to apply it by looking at the document in the cluster lab.

https://www.clusterlabs.org/pacemaker/doc/2.1/Clusters_from_Scratch/html/
should give you an introduction to all the important concepts and
run you through an example.
I don't know how well a translator does with that though.

Klaus

> Please check it out.
> Thank you.
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