Cis Docker V170 2.10

CIS Docker Benchmark v1.7.0 - Control 2.10

Profile Applicability

• Level: 2 - Docker - Linux

Description

The --cgroup-parent option allows you to set the default cgroup parent to use for all containers. If there is no specific usage requirement for this, the setting should be left at its default.

Rationale

System administrators typically define cgroups under which containers are supposed to run. Even if cgroups are not explicitly defined by the system administrators, containers run under docker cgroup by default.

It is possible to attach to a different cgroup other than the one which is the default, however this type of usage should be monitored and confirmed because attaching to a different cgroup other than the one that is default, it could be possible to share resources unevenly causing resource utilization problems on the host.

Impact

None.

Audit Procedure

In order to confirm this setting, the dockerd start-up options and any settings in /etc/docker/daemon.json should be reviewed.

To review the dockerd startup options, use:

ps -ef | grep dockerd

You should ensure that the --cgroup-parent parameter is either not set or is set as appropriate non-default cgroup.

The contents of /etc/docker/daemon.json should also be checked for this setting.

Remediation

The default setting is in line with good security practice and can be left in situ. If you wish to specifically set a non-default cgroup, pass the --cgroup-parent parameter to the Docker daemon when starting it.

For example,

dockerd --cgroup-parent=/foobar

Default Value

By default, docker daemon uses /docker for fs cgroup driver and system.slice for systemd cgroup driver.

References

1. https://docs.docker.com/engine/reference/commandline/dockerd/#default-cgroup-parent

CIS Controls

Profile

Level 2 - Docker - Linux (Manual)