.. _scaling-rhodecode:

==============================
Scaling to handle more traffic
==============================


scaling http traffic
++++++++++++++++++++

In case for bigger setups docker-compose can scale more rhodecode/vcsserver workers:
Adjust the .custom/docker-compose-apps.override.yaml file and change `replicas: NUM`

.. code-block:: yaml

    services:
      rhodecode:
        deploy:
          # set number of instances of services to be spawned on stack start
          replicas: 4

      vcsserver:
        deploy:
          # set number of instances of services to be spawned on stack start
          replicas: 4


Generally replicas of vcsserver and rhodecode should be equal, but each replica should have `workers=N` directive set
to `workers=2` for rhodecode `workers=3` for vcsserver.


Then scale docker replicas without any downtime using this command

.. code-block:: bash

  ./rcstack stack rhodecode up --detach --no-recreate --scale rhodecode=4 --scale vcsserver=4



scaling ssh traffic
+++++++++++++++++++

ssh workers can scale independently from the http traffic handled by rhodecode/vcsserver. To scale for more ssh
traffic, increase replicas for sshd service

.. code-block:: yaml

    services:
      sshd:
        deploy:
          # set number of instances of services to be spawned on stack start
          replicas: 4


scaling celery workers
++++++++++++++++++++++

celery workers can scale independently from the http traffic handled by rhodecode/vcsserver. To scale for more celery
task processing capabilities, increase replicas for celery service.

.. code-block:: yaml

    celery:
      sshd:
        deploy:
          # set number of instances of services to be spawned on stack start
          replicas: 4


.. note::

    Celery already has an autoscaler defined by the command argument called `"--autoscale=20,2".`
    This means that there are min of 2 processes per worker that can scale upto 20 if there are more tasks to process.
    Scaling replicas means the maximum task processing capacity would be defined by replicas * maximum autoscale number.