[ClusterLabs] 答复: No slave is promoted to be master

[Ken Gaillot]

On Thu, 2018-04-12 at 07:29 +0000, 范国腾 wrote:
> Hello,
>  
> We use the following command to create the cluster. Node2 is always
> the master when the cluster starts. Why does pacemaker not select
> node1 as the default master?
> How to configure if we want node1 to be the default master?

You can specify a location constraint giving pgsqld's master role a
positive score (not INFINITY) on node1, or a negative score (not
-INFINITY) on node2. Using a non-infinite score in a constraint tells
pacemaker that it's a preference, but not a requirement.

However, there's rarely a good reason to do that. In HA, the best
practice is that all nodes should be completely interchangeable, so
that the service can run equally on any node (since it might have to,
in a failure scenario). Such constraints can be useful temporarily,
e.g. if you need to upgrade the software on one node, or if one node is
underperforming (perhaps it's waiting on a hardware upgrade to come in,
or running some one-time job consuming a lot of CPU).

>  
> pcs cluster setup --name cluster_pgsql node1 node2
> pcs resource create pgsqld ocf:heartbeat:pgsqlms
> bindir=/usr/local/pgsql/bin pgdata=/home/postgres/data op start
> timeout=600s op stop timeout=60s op promote timeout=300s op demote
> timeout=120s op monitor interval=15s timeout=100s role="Master" op
> monitor interval=16s timeout=100s role="Slave" op notify
> timeout=60s;pcs resource master pgsql-ha pgsqld notify=true
> interleave=true;
>  
>  
> Sometimes it reports the following error, how to configure to avoid
> it?
-- 
Ken Gaillot <kgaillot at redhat.com>