SELinux does not seem to be supported for the Open Source version of DC/OS. Services/Applications like Jenkins or MySQL fail with a permission denied error when deploying the container. But when SELinux was turned off on the nodes of the cluster, the deploy worked.
It's not clear in the docs that SELinux is only for Enterprise.
I'm not sure if it's a bug in the Open Source version or if it is by design and the docs are just missing a clarification around SELinux.
Also, on the bootstrap box, it seems that SELinux also needs to be turned off to have a working bootstrap box to do the installation from.