Docker on Debian
================

To enable docker memory limitation, the kernel needs to be loaded with
boot parameters: cgroup_enable=memory swapaccount=1.

This is because enabling memory cgroup support has some run-time overhead,
and kernel maintainers don't want to slow down systems unnecessarily.

http://www.mail-archive.com/debian-bugs-dist@lists.debian.org/msg764104.html
https://github.com/docker/docker/issues/396

To instruct the kernel to enable memory cgroup support, edit
/etc/default/grub and extend GRUB_CMDLINE_LINUX_DEFAULT like:

GRUB_CMDLINE_LINUX_DEFAULT="cgroup_enable=memory swapaccount=1"

Then run update-grub, and reboot.


As noted in the upstream documentation (https://docs.docker.io), Docker will
allow non-root users in the "docker" group to access "docker.sock" and thus
communicate with the daemon.  To add yourself to the "docker" group, use
something like:

adduser YOURUSER docker

As also noted in the upstream documentation, the "docker" group (and any other
means of accessing the Docker API) is root-equivalent.  If you don't trust a
user with root on your box, you shouldn't trust them with Docker either.  If you
are interested in further information about the security aspects of Docker,
please be sure to read the "Docker Security"
(http://docs.docker.io/en/latest/articles/security/) article in the
upstream documentation.
