How does this work? Given that its PID1 is not a "real" init process but a bash running the script `/google/scripts/onrun.sh` and its / being type `aufs`, I guess this is a Debian Docker instance?
Yep, /etc/debian_version is 9.3. It has a docker0 network interface (among others)
That's for the dockerd which is running inside the ... VM?
The interesting thing is that the uptime and dmesg show that this system is not shared on the kernel level - if I were to guess, I'd say that Google allocates a real virtual machine with a tiny OS running Docker, starts the docker container inside this VM and then grants you webshell/ssh access to this Docker container.
But why the Docker setup when the machine is yours anyway?