Can’t build or push docker container?

Error:

oci runtime error: applying cgroup configuration for process caused mountpoint for devices not found

Try restarting docker. If you then get:

Error starting daemon: Devices cgroup isn't mounted

Then it may be time to shutdown and cold-start the machine.

In my case, I didn’t have to install or config anything new. Docker was running fine before this failure. Try restarting docker (eg. systemctl restart docker). If it fails, shutdown and cold-boot the machine. Ensure docker is running. After 129 days of uptime, my docker just got in a weird, bad state.

See also:

https://stackoverflow.com/questions/32002882/error-starting-docker-daemon-on-ubuntu-14-04-devices-cgroup-isnt-mounted/55657451