Docker failed to start daemon: Devices cgroup isn't mounted [Debian GNU/Linux 9 (stretch) ] armv7l

Question

docker.log

time="2020-02-18T10:05:51.740757000+08:00" level=error msg="'overlay' not found as a supported filesystem on this host. Please ensure kernel is new enough and has overlay support loaded." storage-driver=overlay2 time="2020-02-18T10:05:51.747446000+08:00" level=error msg="AUFS was not found in /proc/filesystems" storage-driver=aufs time="2020-02-18T10:05:51.758181000+08:00" level=error msg="'overlay' not found as a supported filesystem on this host. Please ensure kernel is new enough and has overlay support loaded." storage-driver=overlay time="2020-02-18T10:05:51.990661000+08:00" level=error msg="Udev sync is not supported. This will lead to data loss and unexpected behavior. Install a more recent version of libdevmapper or select a different storage driver. For more information, see https://docs.docker.com/engine/reference/commandline/dockerd/#storage-driver-options" storage-driver=devicemapper time="2020-02-18T10:05:52.146274000+08:00" level=warning msg="Your kernel does not support cgroup memory limit" time="2020-02-18T10:05:52.146389000+08:00" level=warning msg="Unable to find cpu cgroup in mounts" time="2020-02-18T10:05:52.146445000+08:00" level=warning msg="Unable to find blkio cgroup in mounts" time="2020-02-18T10:05:52.146504000+08:00" level=warning msg="Unable to find cpuset cgroup in mounts" time="2020-02-18T10:05:52.146553000+08:00" level=warning msg="mountpoint for pids not found" time="2020-02-18T10:05:52.149506000+08:00" level=info msg="stopping healthcheck following graceful shutdown" module=libcontainerd time="2020-02-18T10:05:52.160535000+08:00" level=info msg="stopping event stream following graceful shutdown" error="context canceled" module=libcontainerd namespace=plugins.moby failed to start daemon: Devices cgroup isn't mounted

docker version

Client: Docker Engine - Community Version: 19.03.6 API version: 1.40 Go version: go1.12.16 Git commit: 369ce74 Built: Thu Feb 13 01:40:25 2020 OS/Arch: linux/arm Experimental: false Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

Answer 1

I am on MX Linux 21.3. It is based on Debian.

In my case cgroup was already mounted (mount told me so, also validated in df), but running sudo dockerd still gave me the same error ("Devices cgroup isn't mounted").

What worked for me was to install a package called cgroupfs-mount.

sudo apt install cgroupfs-mount

After this, sudo service docker start worked.

Reference: https://www.gushiciku.cn/pl/gcx5

Answer 2

I have this literally bookmarked, and I go here every time I need to start docker on my netbooting Alpine. Single command to mount the cgroup pseudofs, w/o touching fstab:

sudo mount -t cgroup cgroup /sys/fs/cgroup

FYI: this may be also caused by your kernel not having cgroup support compiled in, but it's highly unlikely.