doc/mgr: Add cli api documentation

Signed-off-by: Waad AlKhoury <walkhour@redhat.com>

doc/mgr/cli_api.rst

@@ -0,0 +1,39 @@
+CLI API Commands Module
+=======================
+
+The CLI API module exposes most ceph-mgr python API via CLI. Furthermore, this API can be
+benchmarked for further testing.
+
+Enabling
+--------
+
+The *cli api commands* module is enabled with::
+
+  ceph mgr module enable cli_api
+
+To check that it is enabled, run::
+
+  ceph mgr module ls | grep cli_api
+
+Usage
+--------
+
+To run a mgr module command, run::
+
+  ceph mgr cli <command> <param>
+
+For example, use the following command to print the list of servers::
+
+  ceph mgr cli list_servers
+
+List all available mgr module commands with::
+
+  ceph mgr cli --help
+
+To benchmark a command, run::
+
+  ceph mgr cli_benchmark <number of calls> <number of threads> <command> <param>
+
+For example, use the following command to benchmark the command to get osd_map::
+
+  ceph mgr cli_benchmark 100 10 get osd_map

doc/mgr/index.rst

@@ -49,3 +49,4 @@ sensible.
     MDS Autoscaler module <mds_autoscaler>
     NFS module <nfs>
     Progress Module <progress>
+    CLI API Commands module <cli_api>