add docs on vnc_container bc templates (#908)

Add documentation on vnc_container batch connect templates.

source/how-tos/app-development/interactive/submit.rst

@@ -96,23 +96,41 @@ The three possible configuration options that can be used in the
 Each of these configuration options take a set of their own configuration
 options described below.
 
-Configure Batch Connect
-```````````````````````
+Batch Connect Template types
+````````````````````````````
 
-All batch scripts are generated from either the ``basic`` template or the
-``vnc`` template specified with the following configuration option:
+Open OnDemand has three distinct batch connect template types.
+These template types determine the resulting shell scripts that wrap
+your batch connect application.
+
+For example the ``vnc`` type will provide a script that boots up a
+VNC server, exports a ``DISPLAY`` variable and other utilities to
+ensure that the job has been bootstrapped appropriately to
+start GUI applications.
+
+The options available are ``basic``, ``vnc`` or ``vnc_container``.
+``vnc_container`` is basically just like ``vnc`` only in that it
+boostraps the VNC programs inside a container instead of on the
+host machine.
 
 .. describe:: template (String)
 
-   the template used for rendering the batch script (``"basic"`` or ``"vnc"``)
+    The template used to create the wrapper script for your batch connect
+    application.
 
-   Default
-     ``"basic"``
+    Default
+      Generate a basic wrapper script for HTTP applications.
 
-   Example
-     Render a batch script for a VNC Interactive Application
+      .. code-block:: yaml
 
-     .. code-block:: yaml
+        ---
+        batch_connect:
+          template: "basic"
+
+    Example
+      Generate a wrapper script for a VNC interactive application.
+
+      .. code-block:: yaml
 
         # ${HOME}/ondemand/dev/my_app/submit.yml.erb
         ---

source/reference/files/submit-yml-erb.rst

@@ -16,6 +16,7 @@ These are reference pages, you can see
 
    submit-yml/basic-bc-options
    submit-yml/vnc-bc-options
+   submit-yml/vnc-container-bc-options
    submit-yml/script
 
 Simple Example

source/reference/files/submit-yml/vnc-container-bc-options.rst

@@ -0,0 +1,142 @@
+.. _vnc-container-bc-options:
+
+Batch Connect VNC Container Options
+===================================
+
+
+All the options in :ref:`vnc-bc-options` apply in addition to what's listed below.
+
+        # @option context [#to_s] :container_path ("vnc_container.sif") the path
+        #   to the container with VNC
+        # @option context [#to_s] :container_bindpath ("") paths to bind into
+        #   the container with VNC
+        # @option context [#to_s] :container_module ("singularity") the module
+        #   that loads Singularity or Apptainer with Lmod. Supports versions (i.e.
+        #   apptainer/1.10). If Singularity or Apptainer are installed at a 
+        #   system level (i.e., no module loaded to activate), set this to an
+        #   empty string.
+        # @option context [#to_s] :container_command ("singularity") the 
+        #   singularity or apptainer execution command
+
+  .. code-block:: yaml
+  
+    batch_connect:
+      template: "vnc_container"
+      # other 'vnc' or 'basic' options removed for brevity.
+      container_path: "vnc_container.sif"
+      container_bindpath: ""
+      container_module: "singularity"
+      container_command: "singularity"
+
+
+.. describe:: container_path (String, "vnc_container.sif")
+
+    The full path to the container image you wish to boot.
+
+    Default
+      Load the vnc_container.sif image.
+
+      .. code-block:: yaml
+
+        container_path: "vnc_container.sif"
+
+    Example
+      Provide an absolute path to a ``vnc_container.sif`` image.
+
+      .. code-block:: yaml
+
+        container_path: "/absolute/path/to/my/container/vnc_container.sif"
+
+.. describe:: container_bindpath (String, "")
+
+    A comma seperated list of mountpoints you wish to bind into the container.
+
+    Default
+      Do not bind any paths into the container.
+
+      .. code-block:: yaml
+
+        container_bindpath: ""
+
+    Example
+      Bind /etc, /dev and /usr into the container.
+
+      .. code-block:: yaml
+
+        container_bindpath: "/etc,/dev,/usr"
+
+.. describe:: container_module (String, "singularity")
+
+    The module to load before starting the container.
+
+    Default
+      Load the ``singularity`` module.
+
+      .. code-block:: yaml
+
+        container_module: "singularity"
+
+    Example
+      Load the ``singularity/1.1.3`` module.
+
+      .. code-block:: yaml
+
+        container_module: "singularity/1.1.3"
+
+.. describe:: container_command (String, "singularity")
+
+    The command used to start the container.
+
+    Default
+      Use the ``singularity`` command.
+
+      .. code-block:: yaml
+
+        container_module: "singularity"
+
+    Example
+      Use the ``apptainer`` command.
+
+      .. code-block:: yaml
+
+        container_module: "apptainer"
+
+
+Starter def file
+................
+
+This is a ``.def`` file that we've tested this feature with.
+You can use this as an example to start and update as required.
+
+
+.. note::
+  Note that we're installing turbovnc and websockify *inside*
+  the container. This is important as all processes will run
+  inside the contianer and not on the host.
+
+  You can still install these on the host machine, but they will
+  need to be mounted inside the container as the processes are
+  expected to be ran *inside* the container.
+
+.. code-block:: singularity
+
+  Bootstrap: docker
+
+  From: rockylinux/rockylinux:8
+
+  %environment
+    PATH=/opt/TurboVNC/bin:$PATH
+    LANGUAGE="en_US.UTF-8"
+    LC_ALL="en_US.UTF-8"
+    LANG="en_US.UTF-8"
+
+  %post   
+      dnf install -y epel-release
+      dnf groupinstall -y xfce
+      dnf install -y python3-pip xorg-x11-xauth
+      pip3 install ts
+      dnf install -y https://yum.osc.edu/ondemand/latest/compute/el8Server/x86_64/python3-websockify-0.10.0-1.el8.noarch.rpm
+      dnf install -y https://yum.osc.edu/ondemand/latest/compute/el8Server/x86_64/turbovnc-2.2.5-1.el8.x86_64.rpm
+      dnf clean all
+      chown root:root /opt/TurboVNC/etc/turbovncserver-security.conf
+      rm -rf /var/cache/dnf/*