A nice trick with docker is to mount the docker daemon's unix socket into a container, so that container can act as a client to the docker daemon it is running under, e.g.:
docker run ... -v /var/run/docker.sock:/var/run/docker.sock
But this doesn't work with Fedora or RHEL as the host because of their
use of SELinux to harden containers. When the docker client attempts
to access /var/run/docker.sock within the container, you'll get
"Permission denied" errors.
This repo contains a small SELinux module that fixes this issue, allowing containers to access the socket.
Make sure you have the prerequisite SELinux utilities by doing (on RHEL/CentOS/Fedora/etc.):
yum install policycoreutils policycoreutils-python checkpolicy
Then as root, just do
make
Or if you are paranoid, without being root you can do
make dockersock.pp
to build the SELinux policy module package, and then load it as root with
semodule -i dockersock.pp
Should you ever wish to remove the module, do
semodule -r dockersock