Automatically restart Webmin/Virtualmin in case of failure

Running out of memory sometimes happens on swap-less VPSes, and it seems Webmin (together with its twin, Virtualmin) are among the first processes to die in out-of-memory cases.

Setting up a little script to check for and restart Webmin if it is no longer running is a pretty simple (workaround) solution – but should never replace the proper procedure of adjusting the settings or upgrading the VPS to avoid running out of memory in the future.

Emails not visible on freshly installed CentOS 6 with Virtualmin

Main symptom of a problem is that emails are visible in the Read User Mail utility in Webmin but they do not show up in either webmail (Roundcube/Squirrelmail), Usermin or any email client configured to connect to the server.

After further inspection, it appears the emails get delivered to /var/mail/usermailbox@domain.tld instead of /home/username/homes/usermailbox/Maildir.

Bash script to monitor and (re)start Webmin

Webmin (Virtualmin) has great service monitoring capabilities, restarting any failed services that it detects. Unfortunately, it cannot and does not monitor or restart itself it it crashes.

Still, since on (most) Linux systems it comes with a service manager, this can be used to check its status. The included bash script does this and restarts it if necessary…

Configure Munin to graph MySQL on CentOS 5/6 with Virtualmin

If you’re running a CentOS 5/6 VPS/Server with Virtualmin and installed Munin to graph the system stats, you’ll mostly likely notice that the generated graphs do not include MySQL.

This is expected behaviour since Virtualmin asks you to define a root password for your MySQL server (so it isn’t left unsecured out in the open), while Munin tries to read MySQL data using the root account and no password and fails.

But there’s an easy way to fix this…