add new ister guide to toctree

Signed-off-by: Kristal Dale <kristal.dale@intel.com>

source/clear-linux/guides/maintenance/ister.rst

@@ -0,0 +1,94 @@
+.. _ister:
+
+ister
+#####
+
+The `ister.py tool`_ is a template based installer used by |CL-ATTR| to produce
+images for each release. The same ister tool is available for use to create
+custom images based on upstream |CL|.
+
+Description
+***********
+
+|CL| is a rolling release and produces on average 10 releases per week using the
+ister tool. With each release, we produce multiple `different image types`_ for
+different environments and use cases such as installers, Hyper-V, KVM, or
+VMWare.
+
+For each image, we also publish the corresponding JSON configuration file used
+by ister to generate the image. These JSON configuration files describe image
+type, partitions, version, and which bundles will be preinstalled by default
+with the image.
+
+The :ref:`mixer<mixer>` tool uses ister to build an image for your custom mix.
+Like upstream images, a JSON configuration file is defined for the image, which
+ister uses to generate the image.
+
+Configuration files for upstream images may be used to recreate an image, for
+example when you want to:
+
+* Use an older version of |CL| and the image is no longer available (only after
+  March 2017).
+* Customize the partitions of an image.
+* Customize the bundles preinstalled in an image.
+* Run your own post installation script.
+
+How to use ister
+****************
+
+Learn how to use ister to recreate an upstream image. Refer to the
+:ref:`mixer <mixer>` guide for instruction on using ister to build an image for
+a custom mix.
+
+Example: Recreate an upstream image
+===================================
+
+Prerequisites
+-------------
+
+#. |CL| installed.
+
+#. :command:`os-installer` bundle is installed.
+
+#. ister.py has sudo privilege.
+
+Recreate upstream image
+-----------------------
+
+Follow these steps to recreate an upstream image based on the image's JSON
+configuration file:
+
+#. Download the JSON configuration file for the desired image:
+
+   * `Configuration files for the current release`_
+   * `Previous releases`_ (only after March 2017)
+
+   For a previous release, the configuration file for the specific release is
+   located at
+   ``https://cdn.download.clearlinux.org/releases/<version number>/clear/config/image/``
+
+#. The JSON configuration file for the image may have an accompanying
+   “PostNonChroot” script that is executed at the end of the image creation
+   process. If it does, download the script as well and make it executable.
+
+#. Edit the JSON configuration file as needed.
+
+#. If your configuration file has an accompanying "PostNonChroot" script, change
+   the default path of the script to match yours.
+
+#. Generate the new image with the following command:
+
+   .. code-block:: bash
+
+   	sudo ister.py -t [JSON configuration]
+
+Related topics
+**************
+
+* :ref:`mixer`
+* :ref:`bulk-provision`
+
+.. _ister.py tool: https://github.com/bryteise/ister
+.. _different image types: https://cdn.download.clearlinux.org/image/README-IMAGES.html
+.. _Configuration files for the current release: https://cdn.download.clearlinux.org/current/config/image/
+.. _Previous releases: https://cdn.download.clearlinux.org/releases/

source/clear-linux/guides/maintenance/maintenance.rst

@@ -28,3 +28,4 @@ completed.
    download-verify-decompress-windows
    autospec
    assign-static-ip
+   ister