A

agent-plugin

Checkmk extension for a Discourse forum run with discourse_docker: container, installed version against the release channel (latest, release, ESR) including missing security backports, DNS and SMTP from inside the container, Sidekiq, Redis, PostgreSQL, backups, admin dashboard problems and disk space - one docker exec per run, no API key.

Checkmk 2.5 extension that monitors TCP/UDP connections per local port (ESTABLISHED plus optional LISTEN, TIME_WAIT, CLOSE_WAIT, … with per-state thresholds and graphs). Ships its own agent plug-ins for Linux, AIX, Solaris and Windows, deployable via the agent bakery.

Checkmk extension for pending system/package updates on Linux (apt, dnf/yum, zypper, apk) and Windows (Windows Update, winget): security vs. normal updates, update cache age, reboot required and service restart needed - language-independent, never triggers repository rate limiting. Live-tested on 23 Linux distribution versions and Windows 11 / Server 2016 / 2022.