Comment 1 for bug 1712087

I've noticed the same issue using kolla-ansible for Pike release.
From my investigations when mariadb container is stopped the following file /var/lib/docker/volumes/mariadb/_data/gvwstate.dat is deleted.

As an workaround I've created a copy of the gvwstate.dat file before the container was stoped.
Once the mariadb containers were started again I used the back-up file for gvwstate.dat to recover mariadb cluster