Hello,
there is an outstanding request in docker-library/mariadb for Alpine support:
Federico Razzoli has managed to make MariaDB 10.1 work in Alpine with some caveats (no tokudb, no oqgraph, no galera). You can look at his work here
https://hub.docker.com/r/santec/mariadb-alpine/. I admit I don't know about portability of Galera lib on Alpine - should probably talk to Codership about that.
Is there any way we can make this happen?