Support for persistent volumes was added to the docker containerizer in
MESOS-3413. However, this does not work on CentOS 6.
On CentOS 6, the same docker run -v ... operation does not perform a recursive bind, whereas on every other OS supported by Mesos, docker does a recursive bind.
Docker has already dropped support for CentOS 6, so we should add precautionary documentation in case anyone tries to use the docker containerizer on CentOS 6.