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.
Have used both Zabbix and Prometheus for this. Highly recommend Prometheus over Zabbix if you can afford the time to learn it. It’s a bit weird at first but it’s so much easier to extend and manage then Zabbix in my experience.
You will need to set up Grafana to go along with Prometheus. But, again, it’s so flexible that you will end up being happier with it.