Added client config docs

Signed-off-by: Utkarsh Bhatt <[email protected]>

docs/how-to/client-cfg.rst

@@ -0,0 +1,103 @@
+Configure cluster_network/ public_network in Microceph
+======================================================
+
+Similar to :doc:`Cluster Configs <cluster-cfg>` microceph also supports setting, resetting, and listing client configurations which are exported to ceph.conf and are used by tools like qemu directly for configuring rbd cache. Below are the supported client configurations.
+
+
+.. list-table:: Supported Config Keys
+   :widths: 30 70
+   :header-rows: 1
+
+   * - Key
+     - Description
+   * - rbd_cache
+     - Enable caching for RADOS Block Device (RBD).
+   * - rbd_cache_size
+     - The RBD cache size in bytes.
+   * - rbd_cache_writethrough_until_flush
+     - The number of seconds dirty data is in the cache before writeback starts.
+   * - rbd_cache_max_dirty
+     - The dirty limit in bytes at which the cache triggers write-back. If 0, uses write-through caching.
+   * - rbd_cache_target_dirty
+     - The dirty target before the cache begins writing data to the data storage. Does not block writes to the cache.
+
+1. Supported config keys can be configured using the 'set' command:
+
+  .. code-block:: shell
+
+    $ sudo microceph client config set rbd_cache true
+    $ sudo microceph client config set rbd_cache false --host nodeB
+    $ sudo microceph client config set rbd_cache_size 2048MiB --host nodeA
+
+  .. note::
+
+    Host level configuration changes can be made by passing the relevant hostname as the --host parameter.
+
+2. All the client configs can be queried using the 'list' command.
+
+  .. code-block:: shell
+
+    $ sudo microceph cluster config list
+    +---+----------------+---------+----------+
+    | # |      KEY       |  VALUE  |   HOST   |
+    +---+----------------+---------+----------+
+    | 0 | rbd_cache      | true    | nodeA    |
+    +---+----------------+---------+----------+
+    | 1 | rbd_cache      | false   | nodeB    |
+    +---+----------------+---------+----------+
+    | 2 | rbd_cache_size | 2048MiB | nodeA    |
+    +---+----------------+---------+----------+
+
+  Similarly, all the client configs of a particular host can be queried using the --host parameter.
+
+  .. code-block:: shell
+
+    $ sudo microceph cluster config list --host nodeA
+    +---+----------------+---------+----------+
+    | # |      KEY       |  VALUE  |   HOST   |
+    +---+----------------+---------+----------+
+    | 0 | rbd_cache      | true    | nodeA    |
+    +---+----------------+---------+----------+
+    | 1 | rbd_cache_size | 2048MiB | nodeA    |
+    +---+----------------+---------+----------+
+
+
+3. A particular config key can be queried for using the 'get' command:
+
+  .. code-block:: shell
+
+    $ sudo microceph cluster config list
+    +---+----------------+---------+----------+
+    | # |      KEY       |  VALUE  |   HOST   |
+    +---+----------------+---------+----------+
+    | 0 | rbd_cache      | true    | nodeA    |
+    +---+----------------+---------+----------+
+    | 1 | rbd_cache      | false   | nodeB    |
+    +---+----------------+---------+----------+
+
+  Similarly, --host parameter can be used with get command to query for a particular config key/hostname pair.
+
+  .. code-block:: shell
+
+    $ sudo microceph cluster config rbd_cache --host nodeB
+    +---+----------------+---------+----------+
+    | # |      KEY       |  VALUE  |   HOST   |
+    +---+----------------+---------+----------+
+    | 0 | rbd_cache      | false   | nodeB    |
+    +---+----------------+---------+----------+
+
+
+4. Resetting a config key (i.e. removing the configured key/value) can performed using the 'reset' command:
+
+  .. code-block:: shell
+
+   $ sudo microceph cluster config reset rbd_cache_size
+   $ sudo microceph cluster config list
+    +---+----------------+---------+----------+
+    | # |      KEY       |  VALUE  |   HOST   |
+    +---+----------------+---------+----------+
+    | 0 | rbd_cache      | true    | nodeA    |
+    +---+----------------+---------+----------+
+    | 1 | rbd_cache      | false   | nodeB    |
+    +---+----------------+---------+----------+
+