I use some batch scripts in my proxmox installation. They are in cron.hourly and daily checking for virus and ram/CPU load of my LXC containers. An email is send on condition.
What are your tipps or solution without unnecessary load on disc io or CPU time. Lets keep it simple.
Regarding your edit: people are answering the question you posed in your post title, not necessarily giving you advice about how you should do it.