Fixes #255 - Document SELinux labels for mount options

docs/_includes/links/docker.rst

@@ -115,3 +115,26 @@
    <a target="_blank" href="https://docs.docker.com/toolbox/toolbox_install_windows/#optional-add-shared-directories">
      Docker Toolbox on Windows: add shared directories <img src="https://raw.githubusercontent.com/cytopia/icons/master/11x11/ext-link.png" />
    </a>
+
+..
+   ============================================================
+   Docker Documention
+   ============================================================
+
+.. |ext_lnk_docker_bind_propagation| raw:: html
+
+   <a target="_blank" href="https://docs.docker.com/storage/bind-mounts/#configure-bind-propagation">
+     Docker: Configure bind propagation <img src="https://raw.githubusercontent.com/cytopia/icons/master/11x11/ext-link.png" />
+   </a>
+
+.. |ext_lnk_docker_selinux_label| raw:: html
+
+   <a target="_blank" href="https://docs.docker.com/storage/bind-mounts/#configure-the-selinux-label">
+     Docker: Configure the selinux label <img src="https://raw.githubusercontent.com/cytopia/icons/master/11x11/ext-link.png" />
+   </a>
+
+.. |ext_lnk_docker_mount_z_flag| raw:: html
+
+   <a target="_blank" href="https://stackoverflow.com/questions/35218194/what-is-z-flag-in-docker-containers-volumes-from-option/35222815#35222815">
+     Stackoverflow: What is the z flag <img src="https://raw.githubusercontent.com/cytopia/icons/master/11x11/ext-link.png" />
+   </a>

docs/configuration-files/env-file.rst

@@ -787,6 +787,40 @@ downloading libraries with ``composer`` and others.
 Being able to do that on both sides, removes the need to install any development tools (except your
 IDE/editor) on your host and have everything fully encapsulated into the containers itself.
 
+.. _env_mount_options:
+
+MOUNT_OPTIONS
+-------------
+
+This variable allows you to add custom mount options/flags to all mounted directories.
+Initially only ``rw`` or ``ro`` are applied to mount points, you can however extend this
+before starting up the Devilbox.
+
+
++------------------------------+--------------------+----------------+
+| Name                         | Allowed values     | Default value  |
++==============================+====================+================+
+| ``MOUNT_OPTIONS``            | valid mount option | empty          |
++------------------------------+--------------------+----------------+
+
+If you are on Linux with SELinux enabled, you will want to set this value to ``,z`` to modify
+SELinux labels in order to share mounts among multiple container.
+
+.. seealso::
+   * |ext_lnk_docker_bind_propagation|
+   * |ext_lnk_docker_selinux_label|
+   * |ext_lnk_docker_mount_z_flag|
+
+.. important::
+   When adding custom mount options, ensure to start with a leading ``,``, as those options
+   are prepended to already existing options.
+
+   .. code-block:: bash
+
+      MOUNT_OPTIONS=,z
+      MOUNT_OPTIONS=,cached
+
+
 
 .. _env_httpd_datadir:
 

docs/getting-started/install-the-devilbox.rst

@@ -99,6 +99,30 @@ Open the ``.env`` file with your favorite text editor and adjust those values:
    * :ref:`syncronize_container_permissions`
 
 
+OS specific setup
+=================
+
+Linux: SELinux
+--------------
+
+If you have SELinux enabled, you will also have to adjust the :ref:`env_mount_options` to allow
+shared mounts among multiple container:
+
+.. code-block:: bash
+   :caption: .env
+   :emphasize-lines: 3
+
+   host> vi .env
+
+   MOUNT_OPTIONS=,z
+
+.. seealso::
+   * https://github.com/cytopia/devilbox/issues/255
+   * :ref:`env_mount_options`
+   * |ext_lnk_docker_selinux_label|
+   * |ext_lnk_docker_mount_z_flag|
+
+
 Checklist
 =========