Targets

In the world of Kapitan, a target represents a specific environment or deployment scenario where you want to apply your configurations.

Think of it as a blueprint that defines all the necessary settings and parameters for a particular deployment.

For instance, you might have separate targets for production, staging, and development environments, each with its own unique configurations.

Defining targets

Targets are defined as YAML files within the inventory/targets/ directory of your Kapitan project. Each target file typically includes:

classes:
    # A list of classes to inherit configurations from.
    # This allows you to reuse common settings and avoid repetition
    -

parameters:
    # file parameters that override or extend the parameters inherited from previously loaded classes

Example:

# inventory/targets/production/web.yml
classes:
  - common
  - components.nginx

parameters:
  environment: production
  description: ${environment} environment
  nginx:
    replicas: 3
  namespace: ${environment}

In this example, the production.web target:

• Inherits configurations from the common and components.nginx classes.
• Sets the environment parameter to production.
• Overrides (if defined) the replicas for the nginx component to 3.
• Defines the namespace as production using variable interpolation.
• Creates a dynamic description based on the content of the environment variable.

Compiling targets

When you run kapitan compile -t , Kapitan:

• Reads the target file: Kapitan parses the YAML file for the specified target.
• Merges configurations: It merges the parameters from the included classes with the target-specific parameters, giving priority to the target's values.
• Generates output in compiled/target/path/targetname: It uses this merged configuration data, along with the input types and generators, to create the final configuration files for the target environment.

When you run kapitan without the selector, it will run compile for all targets it discovers under the inventory/targets subdirectory.

Target directory structure

Targets are not limited to living directly within the inventory/targets directory.

They can be organized into subdirectories to create a more structured and hierarchical inventory. This is particularly useful for managing large and complex projects.

When targets are organized in subdirectories, Kapitan uses the full path from the targets/ directory to create the target name. This name is then used to identify the target during compilation and in the generated output.

Example for target clusters.production.my-cluster

inventory/
└── targets/
    └── clusters/
        └── production/
            └── my-cluster.yml

In this example, the my-cluster.yml target file is located within the clusters/production/ subdirectory, and can be identified with clusters.production.my-cluster.