Comment 17 for bug 1735097

There is error in /var/log/syslog (similar to https://bugs.launchpad.net/ubuntu/+source/mysql-5.5/+bug/1637280). I had MariaDB installed before running devstack. Devstack purges mariadb* mysql* but maybe some residual configuration was left. will test further.

Dec 8 16:41:15 ubuntu1804 mysql-systemd-start[25028]: 2018-12-09T00:41:15.256901Z 0 [ERROR] Failed to access directory for --secure-file-priv. Please make sure that directory exists and is accessible by MySQL Server. Supplied value : /var/lib/mysql-files