Add a monitoring tool
It'd be useful to have a monitoring tool like nagios or zabbix setup to keep an eye on our services. This is especially true for services like ispconfig and mail which need to be working correctly or people won't get their mail/websites up.
- SSL certificate validity (lets-encrypt renewals)
- Critical services (Git, etc...)
I'm not sure if dockerising it is worth while, or keeping it sperated so if docker blows up it doesn't take the monitoring tool with it (which sounds sensible to me)