Reading /proc/mounts while simultaneously unmounting mountpoints
prevents unmounting all submounts under /var. This is due to the fact
that /proc/mounts will change as we perform unmounts, and that causes a
read of the file to become inaccurate. We now read /proc/mounts into
memory to get a snapshot of all submounts under /var, and then we
proceed with unmounting them.
This also adds some additional logging that I found to be useful while
debugging this. It also adds logic to skip of DaemonSet managed pods.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
