tempest/doc/source/configuration.rst

.. _tempest-configuration:

Tempest Configuration Guide
===========================

This guide is a starting point for configuring tempest. It aims to elaborate
on and explain some of the mandatory and common configuration settings and how
they are used in conjunction. The source of truth on each option is the sample
config file which explains the purpose of each individual option.

Lock Path
---------

There are some tests and operations inside of tempest that need to be
externally locked when running in parallel to prevent them from running at
the same time. This is a mandatory step for configuring tempest and is still
needed even when running serially. All that is needed to do this is:

 #. Set the lock_path option in the oslo_concurrency group

Auth/Credentials
----------------

Tempest currently has 2 different ways in configuration to provide credentials
to use when running tempest. One is a traditional set of configuration options
in the tempest.conf file. These options are in the identity section and let you
specify a regular user, a global admin user, and a alternate user set of
credentials. (which consist of a username, password, and project/tenant name)
These options should be clearly labelled in the sample config file in the
identity section.

The other method to provide credentials is using the accounts.yaml file. This
file is used to specify an arbitrary number of users available to run tests
with. You can specify the location of the file in the
auth section in the tempest.conf file. To see the specific format used in
the file please refer to the accounts.yaml.sample file included in tempest.
Currently users that are specified in the accounts.yaml file are assumed to
have the same set of roles which can be used for executing all the tests you
are running. This will be addressed in the future, but is a current limitation.
Eventually the config options for providing credentials to tempest will be
deprecated and removed in favor of the accounts.yaml file.

Keystone Connection Info
^^^^^^^^^^^^^^^^^^^^^^^^
In order for tempest to be able to talk to your OpenStack deployment you need
to provide it with information about how it communicates with keystone.
This involves configuring the following options in the identity section:

 #. auth_version
 #. uri
 #. uri_v3

The *auth_version* option is used to tell tempest whether it should be using
keystone's v2 or v3 api for communicating with keystone. (except for the
identity api tests which will test a specific version) The 2 uri options are
used to tell tempest the url of the keystone endpoint. The *uri* option is used
for keystone v2 request and *uri_v3* is used for keystone v3. You want to ensure
that which ever version you set for *auth_version* has its uri option defined.


Credential Provider Mechanisms
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Tempest currently also has 3 different internal methods for providing
authentication to tests. Tenant isolation, locking test accounts, and
non-locking test accounts. Depending on which one is in use the configuration
of tempest is slightly different.

Tenant Isolation
""""""""""""""""
Tenant isolation was originally create to enable running tempest in parallel.
For each test class it creates a unique set of user credentials to use for the
tests in the class. It can create up to 3 sets of username, password, and
tenant/project names for a primary user, an admin user, and an alternate user.
To enable and use tenant isolation you only need to configure 2 things:

 #. A set of admin credentials with permissions to create users and
    tenants/projects. This is specified in the identity section with the
    admin_username, admin_tenant_name, and admin_password options
 #. To enable tenant_isolation in the auth section with the
    allow_tenant_isolation option.

This is also the currently the default credential provider enabled by tempest,
due to it's common use and ease of configuration.

It is worth pointing out that depending on your cloud configuration you might
need to assign a role to each of the users created Tempest's tenant isolation.
This can be set using the *tempest_roles* option. It takes in a list of role
names each of which will be assigned to each of the users created by tenant
isolation. This option will not have any effect when set and tempest is not
configured to use tenant isolation.


Locking Test Accounts (aka accounts.yaml or accounts file)
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
For a long time using tenant isolation was the only method available if you
wanted to enable parallel execution of tempest tests. However this was
insufficient for certain use cases because of the admin credentials requirement
to create the credential sets on demand. To get around that the accounts.yaml
file was introduced and with that a new internal credential provider to enable
using the list of credentials instead of creating them on demand. With locking
test accounts each test class will reserve a set of credentials from the
accounts.yaml before executing any of its tests so that each class is isolated
like in tenant isolation.

To enable and use locking test accounts you need do a few things:

 #. Create a accounts.yaml file which contains the set of pre-existing
    credentials to use for testing. To make sure you don't have a credentials
    starvation issue when running in parallel make sure you have at least 2
    times the number of worker processes you are using to execute tempest
    available in the file. (if running serially the worker count is 1)

    You can check the sample file packaged in tempest for the yaml format
 #. Provide tempest with the location of you accounts.yaml file with the
    test_accounts_file option in the auth section

It is worth pointing out that each set of credentials in the accounts.yaml
should have a unique tenant. This is required to provide proper isolation
to the tests using the credentials, and failure to do this will likely cause
unexpected failures in some tests.


Non-locking test accounts (aka credentials config options)
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
When Tempest was refactored to allow for locking test accounts, the original
non-tenant isolated case was converted to internally work similarly to the
accounts.yaml file. This mechanism was then called the non-locking test accounts
provider. To use the non-locking test accounts provider you can specify the sets
of credentials in the configuration file like detailed above with following 9
options in the identity section:

 #. username
 #. password
 #. tenant_name
 #. admin_username
 #. admin_password
 #. admin_tenant_name
 #. alt_username
 #. alt_password
 #. alt_tenant_name

It only makes sense to use it if parallel execution isn't needed, since tempest
won't be able to properly isolate tests using this. Additionally, using the
traditional config options for credentials is not able to provide credentials to
tests which requires specific roles on accounts. This is because the config
options do not give sufficient flexibility to describe the roles assigned to a
user for running the tests. There are additional limitations with regard to
network configuration when using this credential provider mechanism, see the
`Networking`_ section below.

Compute
-------

Flavors
^^^^^^^
For tempest to be able to create servers you need to specify flavors that it
can use to boot the servers with. There are 2 options in the tempest config
for doing this:

 #. flavor_ref
 #. flavor_ref_alt

Both of these options are in the compute section of the config file and take
in the flavor id (not the name) from nova. The *flavor_ref* option is what will
be used for booting almost all of the guests, *flavor_ref_alt* is only used in
tests where 2 different sized servers are required. (for example a resize test)

Using a smaller flavor is generally recommended, when larger flavors are used
the extra time required to bring up servers will likely affect total run time
and probably require tweaking timeout values to ensure tests have ample time to
finish.

Images
^^^^^^
Just like with flavors, tempest needs to know which images to use for booting
servers. There are 2 options in the compute section just like with flavors:

 #. image_ref
 #. image_ref_alt

Both options are expecting an image id (not name) from nova. The *image_ref*
option is what what will be used for booting the majority of servers in tempest.
*image_ref_alt* is used for tests that require 2 images such as rebuild. If 2
images are not available you can set both options to the same image_ref and
those tests will be skipped.

There are also options in the scenario section for images:

 #. img_file
 #. img_dir
 #. aki_img_file
 #. ari_img_file
 #. ami_img_file
 #. img_container_format
 #. img_disk_format

however unlike the other image options these are used for a very small subset
of scenario tests which are uploading an image. These options are used to tell
tempest where an image file is located and describe it's metadata for when it's
uploaded.

The behavior of these options is a bit convoluted (which will likely be fixed
in future versions). You first need to specify *img_dir*, which is the directory
tempest will look for the image files in. First it will check if the filename
set for *img_file* could be found in *img_dir*. If it is found then the
*img_container_format* and *img_disk_format* options are used to upload that
image to glance. However if it's not found tempest will look for the 3 uec image
file name options as a fallback. If neither is found the tests requiring an
image to upload will fail.

It is worth pointing out that using `cirros`_ is a very good choice for running
tempest. It's what is used for upstream testing, they boot quickly and have a
small footprint.

.. _cirros: https://launchpad.net/cirros

Networking
----------
OpenStack has a myriad of different networking configurations possible and
depending on which of the 2 network backends, nova-network or neutron, you are
using things can vary drastically. Due to this complexity Tempest has to provide
a certain level of flexibility in it's configuration to ensure it will work
against any cloud. This ends up causing a large number of permutations in
Tempest's config around network configuration.


Enabling Remote Access to Created Servers
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
When Tempest creates servers for testing, some tests require being able to
connect those servers. Depending on the configuration of the cloud, the methods
for doing this can be different. In certain configurations it is required to
specify a single network with server create calls. Accordingly, Tempest provides
a few different methods for providing this information in configuration to try
and ensure that regardless of the clouds configuration it'll still be able to
run. This section covers the different methods of configuring Tempest to provide
a network when creating servers.

Fixed Network Name
""""""""""""""""""
This is the simplest method of specifying how networks should be used. You can
just specify a single network name/label to use for all server creations. The
limitation with this is that all tenants/projects and users must be able to see
that network name/label if they were to perform a network list and be able to
use it.

If no network name is assigned in the config file and none of the below
alternatives are used, then Tempest will not specify a network on server
creations, which depending on the cloud configuration might prevent them from
booting.

To set a fixed network name simply do:

 #. Set the fixed_network_name option in the compute group

In the case that the configured fixed network name can not be found by a user
network list call, it will be treated like one was not provided except that a
warning will be logged stating that it couldn't be found.


Accounts File
"""""""""""""
If you are using an accounts file to provide credentials for running Tempest
then you can leverage it to also specify which network should be used with
server creations on a per tenant/project and user pair basis. This provides
the necessary flexibility to work with more intricate networking configurations
by enabling the user to specify exactly which network to use for which
tenants/projects. You can refer to the accounts.yaml sample file included in
the tempest repo for the syntax around specifying networks in the file.

However, specifying a network is not required when using an accounts file. If
one is not specified you can use a fixed network name to specify the network to
use when creating servers just as without an accounts file. However, any network
specified in the accounts file will take precedence over the fixed network name
provided. If no network is provided in the accounts file and a fixed network
name is not set then no network will be included in create server requests.

If a fixed network is provided and the accounts.yaml file also contains networks
this has the benefit of enabling a couple more tests which require a static
network to perform operations like server lists with a network filter. If a
fixed network name is not provided these tests are skipped. Additionally, if a
fixed network name is provided it will serve as a fallback in case of a
misconfiguration or a missing network in the accounts file.


With Tenant Isolation
"""""""""""""""""""""
With tenant isolation enabled and using nova-network then nothing changes. Your
only option for configuration is to either set a fixed network name or not.
However, in most cases it shouldn't matter because nova-network should have no
problem booting a server with multiple networks. If this is not the case for
your cloud then using an accounts file is recommended because it provides the
necessary flexibility to describe your configuration. Tenant isolation is not
able to dynamically allocate things as necessary if neutron is not enabled.

With neutron and tenant isolation enabled there should not be any additional
configuration necessary to enable Tempest to create servers with working
networking, assuming you have properly configured the network section to work
for your cloud. Tempest will dynamically create the neutron resources necessary
to enable using servers with that network. Also, just as with the accounts
file, if you specify a fixed network name while using neutron and tenant
isolation it will enable running tests which require a static network and it
will additionally be used as a fallback for server creation. However, unlike
accounts.yaml this should never be triggered.

Configuring Available Services
------------------------------
OpenStack is really a constellation of several different projects which
are running together to create a cloud. However which projects you're running
is not set in stone, and which services are running is up to the deployer.
Tempest however needs to know which services are available so it can figure
out which tests it is able to run and certain setup steps which differ based
on the available services.

The *service_available* section of the config file is used to set which
services are available. It contains a boolean option for each service (except
for keystone which is a hard requirement) set it to True if the service is
available or False if it is not.

Service Catalog
^^^^^^^^^^^^^^^
Each project which has its own REST API contains an entry in the service
catalog. Like most things in OpenStack this is also completely configurable.
However, for tempest to be able to figure out the endpoints to send REST API
calls for each service to it needs to know how that project is defined in the
service catalog. There are 3 options for each service section to accomplish
this:

 #. catalog_type
 #. endpoint_type
 #. region

Setting *catalog_type* and *endpoint_type* should normally give Tempest enough
information to determine which endpoint it should pull from the service
catalog to use for talking to that particular service. However, if you're cloud
has multiple regions available and you need to specify a particular one to use
a service you can set the *region* option in that service's section.

It should also be noted that the default values for these options are set
to what devstack uses. (which is a de facto standard for service catalog
entries) So often nothing actually needs to be set on these options to enable
communication to a particular service. It is only if you are either not using
the same *catalog_type* as devstack or you want Tempest to talk to a different
endpoint type instead of publicURL for a service that these need to be changed.


Service feature configuration
-----------------------------

OpenStack provides its deployers a myriad of different configuration options
to enable anyone deploying it to create a cloud tailor-made for any individual
use case. It provides options for several different backend type, databases,
message queues, etc. However, the downside to this configurability is that
certain operations and features aren't supported depending on the configuration.
These features may or may not be discoverable from the API so the burden is
often on the user to figure out what the cloud they're talking to supports.
Besides the obvious interoperability issues with this it also leaves Tempest
in an interesting situation trying to figure out which tests are expected to
work. However, Tempest tests do not rely on dynamic api discovery for a feature
(assuming one exists). Instead Tempest has to be explicitly configured as to
which optional features are enabled. This is in order to prevent bugs in the
discovery mechanisms from masking failures.

The service feature-enabled config sections are how Tempest addresses the
optional feature question. Each service that has tests for optional features
contains one of these sections. The only options in it are boolean options
with the name of a feature which is used. If it is set to false any test which
depends on that functionality will be skipped. For a complete list of all these
options refer to the sample config file.


API Extensions
^^^^^^^^^^^^^^
The service feature-enabled sections often contain an *api-extensions* option
(or in the case of swift a *discoverable_apis* option) this is used to tell
tempest which api extensions (or configurable middleware) is used in your
deployment. It has 2 valid config states, either it contains a single value
"all" (which is the default) which means that every api extension is assumed
to be enabled, or it is set to a list of each individual extension that is
enabled for that service.