.. title:: Persistent Data

Persistent Data
===============


Overview
--------
Kasm Server allows administrators to configure folders to be mapped inside a Kasm each
time it is provisioned. This is done by configuring the **Volume Mappings** field on the
`Kasm Image <../guide/custom_images.html>`_.

    .. figure:: /images/volume_mappings/volume_mappings.png
      :width: 90%
      :align: center

      **Configuring Volume Mappings on the Kasm Image**


Volume Mappings may also be applied as a `Group Setting <../guide/groups.html#group-settings>`_ . This may be useful
if a certain set of users should have the mapping. When applied at the group level, all Kasms created by members of this
group will have the mapping applied.


    .. figure:: /images/volume_mappings/group_volume_mappings.png
      :width: 60%
      :align: center

      **Configuring Volume Mappings as a Group Setting**


In this guide we will configure a folder on the host ``/var/kasm_persistent_data`` to be mapped inside the Kasm Desktop
image to a folder named ``/data``.  This effectively will act as a file share. All users's who have access to provision
the image will have access to this folder.


Create Host Directory
---------------------
On the Kasm Server create the directory and change the ownership to user and group **1000**.

.. note::
  If Kasm is installed in a multi-server deployment, this process must be repeated on each server that runs the Kasm
  Agent service. ``/var/kasm_persistent_data`` in this example should represent a centralized share that is mapped to
  each agent.

.. code-block:: Bash

    sudo mkdir /var/kasm_persistent_data
    sudo chown 1000:1000 /var/kasm_persistent_data/
    echo "test" > /var/kasm_persistent_data/test.txt


Configure Image Volume Mappings
-------------------------------

* Log into the Kasm UI as an administrator.
* Select Images, and click edit (pencil) next to the Kasm Desktop image
* In the Volume Mappings field, paste the following configuration and click Submit

    .. code-block:: JSON

        {
           "/var/kasm_persistent_data":{
              "bind":"/data",
              "mode":"rw"
           }
        }


.. note::
  Although this guide demonstrate mapping a single volume, multiple volume mappings can be defined.

    .. code-block:: JSON

        {
           "/var/kasm_persistent_data1":{
              "bind":"/data1",
              "mode":"rw"
           },
           "/var/kasm_persistent_data2":{
              "bind":"/data2",
              "mode":"ro"
           }
        }


Verify Access
-------------

* Launch the Kasm Desktop Image.
* Verify the user can read and write to the ``/data`` location.

.. figure:: /images/volume_mappings/verification.png
  :width: 90%
  :align: center

  **Verifying Volume Access**