You can customize and extend the kn CLI by using advanced features, such as configuring a config.yaml file for kn or using plug-ins.

Customizing kn

You can customize your kn CLI setup by creating a config.yaml configuration file. You can provide this configuration by using the --config flag, otherwise the configuration is picked up from a default location. The default configuration location conforms to the XDG Base Directory Specification, and is different for Unix systems and Windows systems.

For Unix systems:

  • If the XDG_CONFIG_HOME environment variable is set, the default configuration location that the kn CLI looks for is $XDG_CONFIG_HOME/kn.

  • If the XDG_CONFIG_HOME environment variable is not set, the kn CLI looks for the configuration in the home directory of the user at $HOME/.config/kn/config.yaml.

For Windows systems, the default kn CLI configuration location is %APPDATA%\kn.

Example configuration file
  path-lookup: true (1)
  directory: ~/.config/kn/plugins (2)
  sink-mappings: (3)
  - prefix: svc (4)
    group: core (5)
    version: v1 (6)
    resource: services (7)
1 Specifies whether the kn CLI should look for plug-ins in the PATH environment variable. This is a boolean configuration option. The default value is false.
2 Specifies the directory where the kn CLI will look for plug-ins. The default path depends on the operating system, as described above. This can be any directory that is visible to the user.
3 The sink-mappings spec defines the Kubernetes addressable resource that is used when you use the --sink flag with a kn CLI command.
4 The prefix you want to use to describe your sink. svc for a service, channel, and broker are predefined prefixes in kn.
5 The API group of the Kubernetes resource.
6 The version of the Kubernetes resource.
7 The plural name of the Kubernetes resource type. For example, services or brokers.

kn plug-ins

The kn CLI supports the use of plug-ins, which enable you to extend the functionality of your kn installation by adding custom commands and other shared commands that are not part of the core distribution. kn CLI plug-ins are used in the same way as the main kn functionality.

Currently, Red Hat supports the kn-source-kafka plug-in.