docker_only=true is not causing any effect in 0.49.1, 0.50 and 0.51.

[Sergiodiaz53]

Hello there,

I'm using cAdvisor 0.49.1 to collect some docker metrics. Im running it with:

docker run --rm gcr.io/cadvisor/cadvisor:v0.49.1 --docker_only=true --enable_metrics=cpu,cpuLoad,diskIO,memory,network,process

even that I'm using --docker_only=true, I'm getting these messages:

Registration of the crio container factory failed: Get "http://%2Fvar%2Frun%2Fcrio%2Fcrio.sock/info": dial unix /var/run/crio/crio.sock: connect: no such file or directory
Registration of the podman container factory failed: failed to validate Podman info: response not present: Get "http://d/v1.0.0/info": dial unix /var/run/podman/podman.sock: connect: no such file or directory
Registration of the mesos container factory failed: unable to create mesos agent client: failed to get version

And even that I'm not adding 'oom_event' to the --enable_metrics flag, im getting:
Could not configure a source for OOM detection, disabling OOM events: open /dev/kmsg: no such file or directory

In 0.47.2 docker_only seems to be working fine, while in both v0.50.0 and v0.51.0 the problem persists.
The OOM detection message appears in all the 4 versions.