Are you running Docker on Raspbian and getting the error:

cgroups: memory cgroup not supported on this system

Best solution is to add cgroup_memory=1 in /boot/cmdline.txt and reboot.

sudo echo "cgroup_memory=1" >> /boot/cmdline.txt

PLease note, for future releases of Raspbian you will need the following instead:

sudo echo "cgroup_enable=memory" >> /boot/cmdline.txt

Alternatively, you can downgrade to an earlier docker version:

sudo apt-get install -y docker-ce=17.09.0~ce-0~raspbian --allow-downgrades