Tempest Configuration Guide

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. You can see the sample config file here: Sample Configuration File

Test Credentials

Tempest allows for configuring a set of admin credentials in the auth section, via the following parameters:

  1. admin_username
  2. admin_password
  3. admin_project_name
  4. admin_domain_name

Admin credentials are not mandatory to run Tempest, but when provided they can be used to:

When Keystone uses a policy that requires domain scoped tokens for admin actions, the flag admin_domain_scope must be set to True. The admin user configured, if any, must have a role assigned to the domain to be usable.

Tempest allows for configuring pre-provisioned test credentials as well. This can be done using the accounts.yaml file (see Pre-Provisioned Credentials). 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.

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. The two 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 has two different internal methods for providing authentication to tests: dynamic credentials and pre-provisioned credentials. Depending on which one is in use the configuration of Tempest is slightly different.

Dynamic Credentials

Dynamic Credentials (formerly known as Tenant isolation) was originally created 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 three sets of username, password, and project names for a primary user, an admin user, and an alternate user. To enable and use dynamic credentials you only need to configure two things:

  1. A set of admin credentials with permissions to create users and projects. This is specified in the auth section with the admin_username, admin_project_name, admin_domain_name and admin_password options
  2. To enable dynamic credentials in the auth section with the use_dynamic_credentials option.

This is also currently the default credential provider enabled by Tempest, due to its 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 by Tempest’s dynamic credentials. 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 dynamic credentials. This option will not have any effect when Tempest is not configured to use dynamic credentials.

When the admin_domain_scope option is set to True, provisioned admin accounts will be assigned a role on domain configured in default_credentials_domain_name. This will make the accounts provisioned usable in a cloud where domain scoped tokens are required by Keystone for admin operations. Note that the initial pre-provision admin accounts, configured in tempest.conf, must have a role on the same domain as well, for Dynamic Credentials to work.

Pre-Provisioned Credentials

For a long time using dynamic credentials 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 with dynamic credentials.

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

  1. Create an 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 two 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 accounts.yaml.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

    NOTE: Be sure to use a full path for the file; otherwise Tempest will likely not find it.

  3. Set use_dynamic_credentials = False in the auth group

It is worth pointing out that each set of credentials in the accounts.yaml should have a unique project. 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. Also, ensure that these projects and users used do not have any pre-existing resources created. Tempest assumes all tenants it’s using are empty and may sporadically fail if there are unexpected resources present.

When the Keystone in the target cloud requires domain scoped tokens to perform admin actions, all pre-provisioned admin users must have a role assigned on the domain where test accounts a provisioned. The option admin_domain_scope is used to tell Tempest that domain scoped tokens shall be used. default_credentials_domain_name is the domain where test accounts are expected to be provisioned if no domain is specified.

Note that if credentials are pre-provisioned via tempest account-generator the role on the domain will be assigned automatically for you, as long as admin_domain_scope as default_credentials_domain_name are configured properly in tempest.conf.

Pre-Provisioned Credentials are also known as accounts.yaml or accounts file.

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 two 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 two 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 two 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 will be used for booting the majority of servers in Tempest. image_ref_alt is used for tests that require two images such as rebuild. If two images are not available you can set both options to the same image id 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 its metadata for when it is 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 in which Tempest will look for the image files. 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 is not found, Tempest will look for the three 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 two 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 its 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

Network Creation/Usage for 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 cloud’s 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 projects and users must be able to see that network name/label if they are 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:

  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 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 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 Dynamic Credentials

With dynamic credentials enabled and using nova-network, 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. Dynamic credentials is not able to dynamically allocate things as necessary if Neutron is not enabled.

With Neutron and dynamic credentials 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 dynamic credentials 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 dynamic credentials’s automatic provisioning of network resources. If this option is set to False 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.

SSH Connection Configuration

There are also several different ways to actually establish a connection and authenticate/login on the server. After a server is booted with a provided network there are still details needed to know how to actually connect to the server. The validation group gathers all the options regarding connecting to and remotely accessing the created servers.

To enable remote access to servers, there are 3 options at a minimum that are used:

  1. run_validation
  2. connect_method
  3. auth_method

The run_validation is used to enable or disable ssh connectivity for all tests (with the exception of scenario tests which do not have a flag for enabling or disabling ssh) To enable ssh connectivity this needs be set to True.

The connect_method option is used to tell Tempest what kind of IP to use for establishing a connection to the server. Two methods are available: fixed and floating, the later being set by default. If this is set to floating Tempest will create a floating ip for the server before attempted to connect to it. The IP for the floating ip is what is used for the connection.

For the auth_method option there is currently, only one valid option, keypair. With this set to keypair Tempest will create an ssh keypair and use that for authenticating against the created server.

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 which endpoints should get REST API calls for each service, it needs to know how that project is defined in the service catalog. There are three 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 your 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.

Note

Tempest does not serve all kinds of fancy URLs in the service catalog. The service catalog should be in a standard format (which is going to be standardized at the Keystone level). Tempest expects URLs in the Service catalog in the following format:

  • http://example.com:1234/<version-info>

Examples:

  • Good - http://example.com:1234/v2.0
  • Wouldn’t work - http://example.com:1234/xyz/v2.0/ (adding prefix/suffix around version etc)

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 types, 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 is supported by the cloud they’re talking to. 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 two 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.

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