#monitoring

A box is slow or swapping. Work through it step by step: measure, find the offender, kill it if needed, then check whether a service — not a one-off process — is the real cause via systemctl and journalctl.

Live CPU, memory, network and disk usage per container, and the processes running inside one: the quick way to find the container hogging resources.

ps takes a snapshot of running processes; top (or htop) watches them live, sorted by resource usage.