kayobe/doc/source/multiple-environments.rst

Multiple Environments

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

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 enviroment 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/

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

Kolla configuration is currently independent in each environment. To avoid duplicating configuration, 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.

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 under the existing configuration. Merging shared configuration must be done manually.