Add tt replicaset status reference (#4185)

Resolves #3966 

Co-authored-by: Andrey Aksenov <38073144+andreyaksenov@users.noreply.github.com>

Author: p7nov

doc/reference/tooling/tt_cli/commands.rst

@@ -56,6 +56,8 @@ help for the given command.
             -   Package an application
         *   -   :doc:`play <play>`
             -   Play the contents of ``.snap`` or ``.xlog`` files to another Tarantool instance
+        *   -   :doc:`replicaset <replicaset>`
+            -   Manage a replica set
         *   -   :doc:`restart <restart>`
             -   Restart a Tarantool instance
         *   -   :doc:`rocks <rocks>`
@@ -102,6 +104,7 @@ help for the given command.
     logrotate <logrotate>
     pack <pack>
     play <play>
+    replicaset <replicaset>
     restart <restart>
     rocks <rocks>
     run <run>

doc/reference/tooling/tt_cli/replicaset.rst

@@ -0,0 +1,171 @@
+.. _tt-replicaset:
+
+Working with replicasets
+=========================
+
+..  code-block:: console
+
+    $ tt replicaset COMMAND {APPLICATION[:APP_INSTANCE] | URI} [OPTIONS ...]
+    # or
+    $ tt rs COMMAND {APPLICATION[:APP_INSTANCE] | URI} [OPTIONS ...]
+
+``tt replicaset`` (or ``tt rs``) manages a Tarantool replica set.
+
+``COMMAND`` is one of the following:
+
+*   :ref:`status <tt-replicaset-status>`
+*   :ref:`promote <tt-replicaset-promote>`
+*   :ref:`demote <tt-replicaset-demote>`
+
+
+.. _tt-replicaset-status:
+
+status
+------
+
+..  code-block:: console
+
+    $ tt replicaset status {APPLICATION[:APP_INSTANCE] | URI} [OPTIONS ...]
+    # or
+    $ tt rs status  {APPLICATION[:APP_INSTANCE] | URI} [OPTIONS ...]
+
+``tt replicaset status`` (``tt rs status``) shows the current status of a replica set.
+
+
+.. _tt-replicaset-status-application:
+
+Displaying status of all replica sets
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To view the status of all replica sets of an application in the current ``tt``
+environment, run ``tt replicaset status`` with the application name:
+
+..  code-block:: console
+
+    $ tt replicaset status myapp
+
+.. _tt-replicaset-status-instance:
+
+Displaying status of a single replica set
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To view the status of a single replica set of an application, run ``tt replicaset status``
+with a name or a URI of an instance from this replica set:
+
+..  code-block:: console
+
+    $ tt replicaset status myapp:storage-001-a
+
+For a replica outside the current ``tt`` environment, specify its URI and access credentials:
+
+..  code-block:: console
+
+    $ tt replicaset status 192.168.10.10:3301 -u myuser -p p4$$w0rD
+
+Learn about other ways to provide user credentials in :ref:`tt-replicaset-status-authentication`.
+
+.. _tt-replicaset-status-authentication:
+
+Authentication
+~~~~~~~~~~~~~~
+
+Use one of the following ways to pass the credentials of a Tarantool user when
+connecting to the instance:
+
+*   The ``-u`` (``--username``) and ``-p`` (``--password``) options:
+
+    ..  code-block:: console
+
+        $ tt replicaset status 192.168.10.10:3301 -u myuser -p p4$$w0rD
+
+*   The connection string:
+
+    ..  code-block:: console
+
+        $ tt replicaset status myuser:p4$$w0rD@192.168.10.10:3301
+
+*   Environment variables ``TT_CLI_USERNAME`` and ``TT_CLI_PASSWORD``:
+
+    ..  code-block:: console
+
+        $ export TT_CLI_USERNAME=myuser
+        $ export TT_CLI_PASSWORD=p4$$w0rD
+        $ tt replicaset status 192.168.10.10:3301
+
+.. _tt-replicaset-status-force:
+
+Selecting the application orchestrator manually
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+You can specify the orchestrator to use for the application using the following options:
+
+*   ``--config`` for applications that use YAML cluster configuration (Tarantool 3.x or later).
+*   ``--cartridge`` for Cartridge applications (Tarantool 2.x).
+*   ``--custom`` for any other orchestrators used on Tarantool 2.x clusters.
+
+..  code-block:: console
+
+    $ tt replicaset status myapp --config
+    $ tt replicaset status my-cartridge-app --cartridge
+
+If an actual orchestrator that the application uses does not match the specified
+option, an error is raised.
+
+
+.. _tt-replicaset-status-options:
+
+Options
+~~~~~~~
+
+..  option:: --cartridge
+
+    Force the Cartridge orchestrator for Tarantool 2.x clusters.
+
+..  option:: --config
+
+    Force the YAML configuration orchestrator for Tarantool 3.0 or later clusters.
+
+..  option:: --custom
+
+    Force a custom orchestrator for Tarantool 2.x clusters.
+
+..  option:: -u USERNAME, --username USERNAME
+
+    A Tarantool user for connecting to the instance.
+
+..  option:: -p PASSWORD, --password PASSWORD
+
+    The user's password.
+
+..  option:: --sslcertfile FILEPATH
+
+    The path to an SSL certificate file for encrypted connections.
+
+..  option:: --sslkeyfile FILEPATH
+
+    The path to a private SSL key file for encrypted connections.
+
+..  option:: --sslcafile FILEPATH
+
+    The path to a trusted certificate authorities (CA) file for encrypted connections.
+
+..  option:: --sslciphers STRING
+
+    The list of SSL cipher suites used for encrypted connections, separated by colons (``:``).
+
+.. _tt-replicaset-promote:
+
+promote
+-------
+
+``tt replicaset promote`` (``tt rs promote``) promotes an instance.
+
+.. _tt-replicaset-demote:
+
+demote
+------
+
+``tt replicaset demote`` (``tt rs demote``) demotes an instance.
+
+
+