[debian-mysql] Bug#991839: Bug#991839: mariadb-server-10.3: MariaDB intermittantly not starting on boot on AWS EC2 t2.medium instance

[Daniel Black]

Jeremy,

You are correct in that this is due to one of the hardening directives
in the service file Protect{Home,System} or PrivateDevices that is
trying to be applied before the kernel/system has completed the
underlying mounts on which they depend.

Without these hardening directives, and without
PermissionsStartOnly=true and all of the ExecStartPre= directives the
system is pretty secure as the mysqld/mariadbd process is run under
the non-privileged mysql user which ordinary cannot perform the
restricted items. Being a tiny VM I'm assuming this is the only
services there.

systemd-analyze dump (hint from
https://freedesktop.org/wiki/Software/systemd/Debugging/#reportingsystemdbugs-
Information to Attach to a Bug Report) may include some timing
information of services to verify. The logs since boot `journalctl -b`
might give enough information to see what ordering is happening at
boot.

kernel argument systemd.log_level=debug will include more information
in the mariadb.service journal `journalctl -u mariadb.service
--priority=7` such that the specific mount/system call might be able
to be identified. systemd.log_level=debug will probably make the
journalctl -b too verbose to read