Things about CheckMK not (easily) found in the documentation.
Every host is
pinged, this service is named "Check_MK".
Run containerized version in podman with
podman --cap-add net_raw for ping to work
Install Plugins in containerized Raw edition:
$ podman exec -it -u cmk checkmk /bin/bash OMD[cmk]:~$ cd /tmp OMD[cmk]:~$ curl https://raw.githubusercontent.com/f-zappa/check_mk_adsl_line/master/adsl_line-1.3.mkp OMD[cmk]:~$ mkp install adsl_line-1.3.mkp
- has systemd v219, the agent requires 220. remedy: "legacy mode"
- avoid xinetd? use Agent over SSH
- ssh known_hosts in checkmk container: run
cmk --check $hostname which lets "the correct" ssh ask for accepting the host key.
podman -u cmk $containername /bin/ssh $hostname did not suffice in my case
checkmk defaults to IPv4 only, change in Settings > Folder "Main" > Dual stack. Selecting "both" will do ping4 and ping6 checks separately.
podman container gets no public route, only link-local (fe80:), thus IPv6 pings to public addresses fail. Apparently an open issue: https://github.com/containers/podman/issues/15850.