Why does `gluster add-brick' fail when used with fully qualified domain name?

Issue

• We are attempting to add a brick to expand our storage volume but the gluster cli fails, even for new bricks.

gluster volume add-brick <volume_1> <hostname_1_fqdn>:/<brick_1>/glusterfs <hostname_2_fqdn>:/<brick_1>/glusterfs <hostname_1_fqdn>:/<brick_2>/glusterfs <hostname_2_fqdn>:/<brick_2>/glusterfs

• Following the first failed attempt, we restarted glusterd on all servers in the cluster, then performed the following procedure on all new bricks before trying add-brick again.

  • Remove all subdirectories including .glusterd
  • Remove all extended attributes
  • Check with "getfattr -m trusted.* //glusterfs; ls -a //glusterfs" and similar for all new bricks

• Using empty bricks without any extended attributes the result was the same: "Add Brick unsuccessful"

• New nodes were probed using hostnames/short names but the add-brick was performed using fully qualified hostnames, we need to know the root cause.