Development: Add documentation for local multiple Artemis instances s…

…etup (#7492)

docs/admin/setup/distributed.rst

@@ -502,3 +502,34 @@ It relays message between instances:
 
    .. figure:: distributed/registry.png
       :align: center
+
+
+Running multiple instances locally
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+For testing purposes, you can also run multiple instances on the same machine. You can do this by using
+different ports and a unique instance ID for each instance.
+
+#. In ``application-local.yml``, add the following configuration:
+
+   .. code:: yaml
+
+     eureka:
+         client:
+             enabled: true
+
+#. Create additional run configurations for each instance. You will have to add CLI arguments to each additional run
+   configuration to set the instance ID and the port, e.g. ``--server.port=8081 --eureka.instance.instanceId="Artemis:2"``.
+   Also, make sure that only one instance has the ``scheduling`` profile enabled:
+
+   .. figure:: distributed/run-config.png
+      :align: center
+
+
+#. Start the registry service, e.g., by running ``docker compose -f docker/broker-registry.yml up``.
+
+#. Start the first instance with the default run configuration (no additional CLI arguments, ``scheduling`` enabled)
+   and wait until it is up and running.
+
+#. Start the remaining instances.
+
+You should now be able to see all instances in the registry interface at ``http://localhost:8761``.