@@ -68,3 +68,69 @@ These config options are defined in `nova.conf.serial_console

 For more information on OpenStack configuration see the `OpenStack

 Compute Service Configuration Reference

 <https://docs.openstack.org/nova/latest/admin/configuration/index.html>`_

+

+

+Fake virt driver

+================

+

+Nova has a `fake virt driver`_ which can be used for scale testing the control

+plane services or testing "move" operations between fake compute nodes, for

+example cold/live migration, evacuate and unshelve.

+

+The fake virt driver does not communicate with any hypervisor, it just reports

+some fake resource inventory values and keeps track of the state of the

+"guests" created, moved and deleted. It is not feature-complete with the

+compute API but is good enough for most API testing, and is also used within

+the nova functional tests themselves so is fairly robust.

+

+.. _fake virt driver: http://git.openstack.org/cgit/openstack/nova/tree/nova/virt/fake.py

+

+Configuration

+-------------

+

+Set the following in your devstack ``local.conf``:

+

+.. code-block:: ini

+

+  [[local|localrc]]

+  VIRT_DRIVER=fake

+  NUMBER_FAKE_NOVA_COMPUTE=<number>

+

+The ``NUMBER_FAKE_NOVA_COMPUTE`` variable controls the number of fake

+``nova-compute`` services to run and defaults to 1.

+

+When ``VIRT_DRIVER=fake`` is used, devstack will disable quota checking in

+nova and neutron automatically. However, other services, like cinder, will

+still enforce quota limits by default.

+

+Scaling

+-------

+

+The actual value to use for ``NUMBER_FAKE_NOVA_COMPUTE`` depends on factors

+such as:

+

+* The size of the host (physical or virtualized) on which devstack is running.

+* The number of API workers. By default, devstack will run ``max($nproc/2, 2)``

+  workers per API service. If you are running several fake compute services on

+  a single host, then consider setting ``API_WORKERS=1`` in ``local.conf``.

+

+In addition, while quota will be disabled in neutron, there is no fake ML2

+backend for neutron so creating fake VMs will still result in real ports being

+created. To create servers without networking, you can specify ``--nic=none``

+when creating the server, for example:

+

+.. code-block:: shell

+

+  $ openstack --os-compute-api-version 2.37 server create --flavor cirros256 \

+      --image cirros-0.3.5-x86_64-disk --nic none --wait test-server

+

+.. note:: ``--os-compute-api-version`` greater than or equal to 2.37 is

+          required to use ``--nic=none``.

+

+To avoid overhead from other services which you may not need, disable them in

+your ``local.conf``, for example:

+

+.. code-block:: ini

+

+  disable_service horizon

+  disable_service tempest