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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:

  1. 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:

  1. auth_version
  2. uri
  3. 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:

  1. 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
  2. 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:

  1. 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

  2. Provide tempest with the location of your accounts.yaml file with the test_accounts_file option in the auth section

  3. Set allow_tenant_isolation = False in the auth group

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:

  1. username
  2. password
  3. tenant_name
  4. admin_username
  5. admin_password
  6. admin_tenant_name
  7. alt_username
  8. alt_password
  9. alt_tenant_name

And in the auth secion:

  1. allow_tenant_isolation = False
  2. comment out 'test_accounts_file' or keep it as empty

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:

  1. flavor_ref
  2. 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:

  1. image_ref
  2. 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:

  1. img_file
  2. img_dir
  3. aki_img_file
  4. ari_img_file
  5. ami_img_file
  6. img_container_format
  7. 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.

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:

  1. 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.

However, there is an option create_isolated_networks to disable tenant isolation's automatic provisioning of network resources. If this option is used you will have to either rely on there only being a single/default network available for the server creation, or use fixed_network_name to inform Tempest which network to use.

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:

  1. catalog_type
  2. endpoint_type
  3. 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.