During installation, we filled in the machine’s fully qualified domain name (FQDN), which can be rather long when it appears in cluster logs and status output. See for yourself how the machine identifies itself:

[root@pcmk-1 ~]# uname -n
pcmk-1.localdomain

We can use the hostnamectl tool to strip off the domain name:

[root@pcmk-1 ~]# hostnamectl set-hostname $(uname -n | sed s/\\..*//)

Now, check that the machine is using the correct name:

[root@pcmk-1 ~]# uname -n
pcmk-1

You may want to reboot to ensure all updates take effect.