kayobe/doc/source/multiple-environments.rst

Multiple Environments

Warning

Support for multiple Kayobe environments is considered experimental: its design may change in future versions without a deprecation period.

Sometimes it can be useful to support deployment of multiple environments from a single Kayobe configuration. Most commonly this is to support a deployment pipeline, such as the traditional development, test, staging and production combination. Since the Wallaby release, it is possible to include multiple environments within a single Kayobe configuration, each providing its own Ansible inventory and variables. This section describes how to use multiple environments with Kayobe.

Defining Kayobe Environments

By default, a Kayobe configuration directory contains a single environment, represented by the Ansible inventory located at $KAYOBE_CONFIG_PATH/inventory, extra variables files ($KAYOBE_CONFIG_PATH/*.yml), custom Ansible playbooks and hooks, and Kolla configuration.

Supporting multiple environments is done through a $KAYOBE_CONFIG_PATH/environments directory, under which each directory represents a different environment. Each environment contains its own Ansible inventory, extra variable files, and Kolla configuration. The following layout shows two environments called staging and production within a single Kayobe configuration.

$KAYOBE_CONFIG_PATH/
└── environments/
    ├── production/
    │   ├── inventory/
    │   │   ├── groups
    │   │   ├── group_vars/
    │   │   ├── hosts
    │   │   ├── host_vars/
    │   │   └── overcloud
    │   ├── kolla/
    │   │   ├── config/
    │   │   ├── globals.yml
    │   │   └── passwords.yml
    │   ├── network-allocation.yml
    │   ├── networks.yml
    │   └── overcloud.yml
    └── staging/
        ├── inventory/
        │   ├── groups
        │   ├── group_vars/
        │   ├── hosts
        │   ├── host_vars/
        │   └── overcloud
        ├── kolla/
        │   ├── config/
        │   ├── globals.yml
        │   └── passwords.yml
        ├── network-allocation.yml
        ├── networks.yml
        └── overcloud.yml

Naming

The environment name kayobe is reserved for internal use. The name should be a valid directory name, otherwise there are no other restrictions.

Ansible Inventories

Each environment can include its own inventory, which overrides any variable declaration done in the shared inventory. Typically, a shared inventory may be used to define groups and group variables, while hosts and host variables would be set in environment inventories. The following layout (ignoring non-inventory files) shows an example of multiple inventories.

$KAYOBE_CONFIG_PATH/
├── environments/
│   ├── production/
│   │   ├── inventory/
│   │   │   ├── hosts
│   │   │   ├── host_vars/
│   │   │   └── overcloud
│   └── staging/
│       ├── inventory/
│       │   ├── hosts
│       │   ├── host_vars/
│       │   └── overcloud
└── inventory/
    ├── groups
    └── group_vars/

Custom Kolla Ansible inventories

Kayobe has a feature <custom_kolla_inventory> to pass through additional inventories to Kolla Ansible. When using multiple environments, these are passed though as additional inventories to Ansible. The ordering is such that the inventory in the base layer of kayobe config overrides the internal kayobe inventory, and inventory in the environment overrides inventory in the base layer:

ansible-playbook -i <internal kayobe inventory> -i <inventory from base layer> -i <inventory from environment>

See custom_kolla_inventory for more details.

Shared Extra Variables Files

All of the extra variables files in the Kayobe configuration directory ($KAYOBE_CONFIG_PATH/*.yml) are shared between all environments. Each environment can override these extra variables through environment-specific extra variables files ($KAYOBE_CONFIG_PATH/environments/<environment>/*.yml).

This means that all configuration in shared extra variable files must apply to all environments. Where configuration differs between environments, move the configuration to extra variables files under each environment.

For example, to add environment-specific DNS configuration for variables in dns.yml, set these variables in $KAYOBE_CONFIG_PATH/environments/<environment>/dns.yml:

$KAYOBE_CONFIG_PATH/
├── dns.yml
└── environments/
    ├── production/
    │   ├── dns.yml
    └── staging/
        └── dns.yml

Network Configuration

Networking is an area in which configuration is typically specific to an environment. There are two main global configuration files that need to be considered: networks.yml and network-allocation.yml.

Move the environment-specific parts of this configuration to environment-specific extra variables files:

• networks.yml -> $KAYOBE_CONFIG_PATH/environments/<environment>/networks.yml
• network-allocation.yml -> $KAYOBE_CONFIG_PATH/environments/<environment>/network-allocation.yml

Other network configuration that may differ between environments includes:

• DNS (dns.yml)
• network interface names, which may be set via group variables in environment inventories

Other Configuration

Typically it is necessary to customise overcloud_group_hosts_map in each environment. This is done via the overcloud.yml file documented in control-plane-service-placement.

When using baremetal compute nodes, allocation of TCP ports for serial console functionality is typically specific to an environment (console-allocation.yml). This file is automatically managed by Kayobe, like the network-allocation.yml file.

Kolla Configuration

In the Wallaby release, Kolla configuration was independent in each environment. The Xena release supported combining environment-specific and shared configuration file content for the following subset of the files:

• kolla/config/bifrost/bifrost.yml
• kolla/config/bifrost/dib.yml
• kolla/config/bifrost/servers.yml
• kolla/globals.yml
• kolla/kolla-build.conf
• kolla/repos.yml or kolla/repos.yaml

The Antelope release expands upon this list to add support for combining Kolla Ansible custom service configuration. This behaviour is configured using two variables:

• kolla_openstack_custom_config_include_globs: Specifies which files are considered when templating the Kolla configuration. The Kayobe defaults are set using kolla_openstack_custom_config_include_globs_default. An optional list of additional globs can be set using: kolla_openstack_custom_config_include_globs_extra. These are combined with kolla_openstack_custom_config_include_globs_default to produce kolla_openstack_custom_config_include_globs. Each list entry is a dictionary with the following keys:

  • enabled: Boolean which determines if this rule is used. Set to false to disable the rule.
  • glob: String glob matching a relative path in the kolla/config directory

  An example of such a rule:

  enabled: '{{ kolla_enable_aodh | bool }}'
  glob: aodh/**

• kolla_openstack_custom_config_rules: List of rules that specify the strategy to use when generating a particular file. The Kayobe defaults are set using kolla_openstack_custom_config_rules_default. An optional list of additional rules can be set using: kolla_openstack_custom_config_rules_extra. These are combined with kolla_openstack_custom_config_rules_default to produce kolla_openstack_custom_config_rules. Each list entry is a dictionary with the format:

  • glob: A glob matching files for this rule to match on (relative to the search path)
  • priority: The rules are processed in increasing priority order with the first rule matching taking effect
  • strategy: How to process the matched file. One of copy, concat, template, merge_configs, merge_yaml
  • params: Optional list of additional params to pass to module enacting the strategy

  An example of such a rule:

  glob: a/path/test.yml
  strategy: merge_yaml
  priority: 1000
  params:
    extend_lists: true

The Kayobe defaults fallback to using the template strategy, with a priority of 65535. To override this behaviour configure a rule with a lower priority e.g:

glob: horizon/themes/**
strategy: copy
priority: 1000

The default INI merging strategy can be configured using: kolla_openstack_custom_config_ini_merge_strategy_default. It defaults to concat for backwards compatibility. An alternative strategy is merge_configs which will merge the two INI files so that values set in the environment take precedence over values set in the shared files. The caveat with the merge_configs strategy is that files must template to valid INI. This is mostly an issue when you use raw Jinja tags, for example:

[defaults]
{% raw %}
{% if inventory_hostname in 'compute' %}
foo=bar
{% else %}
foo=baz
{% endif %}
{% endraw %}

After the first round of templating by Kayobe the raw tags are stripped. This leaves:

[defaults]
{% if inventory_hostname in 'compute' %}
foo=bar
{% else %}
foo=baz
{% endif %}

Which isn't valid INI (due to the Jinja if blocks) and cannot be merged. In most cases the templating can be refactored:

[defaults]
{% raw %}
foo={{ 'bar' if inventory_hostname in 'compute' else 'baz' }}
{% endraw %}

Alternatively, you can use Kolla host or group variables.

Disabling the default rules

There are some convenience variables to disable a subset of the rules in kolla_openstack_custom_config_rules_default:

• kolla_openstack_custom_config_rules_default_remove: Allows you remove a rule by matching on the glob:

  kolla_openstack_custom_config_rules_default_remove:
     - "**/*.ini"

• kolla_openstack_custom_config_merge_configs_enabled: Enables rules for matching INI files. Default is true.

• kolla_openstack_custom_config_merge_yaml_enabled: Enables rules for matching YAML files. Default is true.

These allow you to more easily keep in sync with the upstream defaults. If you had an override on kolla_openstack_custom_config_rules, that replicated most of kolla_openstack_custom_config_rules_default you'd have to keep this in sync with the upstream kayobe defaults.

Search paths

When merging config files the following locations are "searched" to find files with an identical relative path:

• <environment-path>/kolla/config
• <shared-files-path>/kolla/config
• <kolla-openstack-role-path>/templates/kolla/config

Not all strategies use all of the files when generating the kolla config. For instance, the copy strategy will use the first file found when searching each of the paths.

There is a feature flag: kolla_openstack_custom_config_environment_merging_enabled, that may be set to false to prevent Kayobe searching the shared files path when merging configs. This is to replicate the legacy behaviour where the environment Kolla custom service configuration was not merged with the base layer. We still merge the files with Kayobe's defaults in the kolla-openstack role's internal templates.

Managing Independent Environment Files

For files that are independent in each environment, i.e. they do not support combining the environment-specific and shared configuration file content, there are some techniques that may be used to avoid duplication.

For example, symbolic links can be used to share common variable definitions. It is advised to avoid sharing credentials between environments by making each Kolla passwords.yml file unique.

Custom Ansible Playbooks and Hooks

The following files and directories are currently shared across all environments:

• Ansible playbooks, roles and requirements file under $KAYOBE_CONFIG_PATH/ansible
• Ansible configuration at $KAYOBE_CONFIG_PATH/ansible.cfg and $KAYOBE_CONFIG_PATH/kolla/ansible.cfg
• Hooks under $KAYOBE_CONFIG_PATH/hooks

Dynamic Variable Definitions

It may be beneficial to define variables in a file shared by multiple environments, but still set variables to different values based on the environment. The Kayobe environment in use can be retrieved within Ansible via the kayobe_environment variable. For example, some variables from $KAYOBE_CONFIG_PATH/networks.yml could be shared in the following way:

external_net_fqdn: "{{ kayobe_environment }}-api.example.com"

This would configure the external FQDN for the staging environment at staging-api.example.com, while the production external FQDN would be at production-api.example.com.

Environment Dependencies

Warning

This is an experimental feature and is still subject to change whilst the design is finalised.

Since the Antelope 14.0.0 release, multiple environments can be layered on top of each of each other by declaring dependencies in a .kayobe-environment file located in the environment subdirectory. For example:

dependencies:
  - environment-B

dependencies:
  - environment-A

Kayobe uses a dependency resolver to order these environments into a linear chain. Any dependency cycles in will result in an error. Using the example above the chain would be resolved to:

C -> B -> A

Where C is the environment with highest precedence. Kayobe will make sure to include the inventory and extra-vars in an order matching this chain when running any playbooks.

Mixin environments

Environment dependencies can be used to design fragments of re-useable configuration that can be shared across multiple environments. For example:

dependencies:
  - environment-mixin-1
  - environment-mixin-2
  - environment-mixin-3

In this case, each environment dependency could provide the configuration necessary for one or more features. The mixin environments do not necessarily need to define any dependencies between them, however Kayobe will perform a topological sort to determine a suitable precedence. Care should be taken to make sure that environments without an explicit ordering do not modify the same variables.

Final Considerations

While it's clearly desirable to keep staging functionally as close to production, this is not always possible due to resource constraints and other factors. Test and development environments can deviate further, perhaps only providing a subset of the functionality available in production, in a substantially different environment. In these cases it will clearly be necessary to use environment-specific configuration in a number of files. We can't cover all the cases here, but hopefully we've provided a set of techniques that can be used.

Using Kayobe Environments

Once environments are defined, Kayobe can be instructed to manage them with the $KAYOBE_ENVIRONMENT environment variable or the --environment command-line argument:

(kayobe) $ kayobe control host bootstrap --environment staging

(kayobe) $ export KAYOBE_ENVIRONMENT=staging
(kayobe) $ kayobe control host bootstrap

The kayobe-env environment file in kayobe-config can also take an --environment argument, which exports the KAYOBE_ENVIRONMENT environment variable.

(kayobe) $ source kayobe-env --environment staging
(kayobe) $ kayobe control host bootstrap

Finally, an environment name can be specified under $KAYOBE_CONFIG_ROOT/.environment, which will be used by the kayobe-env script if no --environment argument is used. This is particularly useful when using a separate branch for each environment.

(kayobe) $ echo "staging" > .environment
(kayobe) $ source kayobe-env
(kayobe) $ kayobe control host bootstrap

Warning

The locations of the Kolla Ansible source code and Python virtual environment remain the same for all environments when using the kayobe-env file. When using the same control host to manage multiple environments with different versions of Kolla Ansible, clone the Kayobe configuration in different locations, so that Kolla Ansible source repositories and Python virtual environments will not conflict with each other. The generated Kolla Ansible configuration is also shared: Kayobe will store the name of the active environment under $KOLLA_CONFIG_PATH/.environment and produce a warning if a conflict is detected.

Migrating to Kayobe Environments

Kayobe users already managing multiple environments will already have multiple Kayobe configurations, whether in separate repositories or in different branches of the same repository. Kayobe provides the kayobe environment create command to help migrating to a common repository and branch with multiple environments. For example, the following commands will create two new environments for production and staging based on existing Kayobe configurations.

(kayobe) $ kayobe environment create --source-config-path ~/kayobe-config-prod/etc/kayobe \
               --environment production
(kayobe) $ kayobe environment create --source-config-path ~/kayobe-config-staging/etc/kayobe \
               --environment staging

This command recursively copies files and directories (except the environments directory if one exists) under the existing configuration to a new environment. Merging shared configuration must be done manually.