set-namespace

set-namespace #

Overview #

The set-namespace function update or add namespace to all namespaced resources. Kubernetes supports multiple virtual clusters backed by the same physical cluster through namespaces.

Namespaces are often used in the following scenarios:

• Separate resources between environments (prod, staging and test).
• Separate resources between different team or users to divide resource quota.

You can learn more about namespace here.

Usage #

This function can be used with any KRM function orchestrators (e.g. kpt).

For all namespaced resurces, the set-namespace function adds the namespace if metadata.namespace doesn’t exist. Otherwise, it updates the existing value. It will skip the resources that are known to be cluster-scoped (e.g. Node , CustomResourceDefinitions, ClusterRole). Whether a resource is namespaced is determined by the OpenAPI schema. If the API path contains namespaces/{namespace} then the resource is considered namespaced. Otherwise, it’s not. Currently, this function is using API version 1.20.4.

In addition to updating the metadata.namespace field for applicable resources, by default the function will also update the [fields][commonnamespace] that target the namespace. There are a few cases that worth pointing out:

• If there is a Namespace resource, its metadata.name field will be updated.
• If it’s a RoleBinding or ClusterRoleBinding resource, subject can reference either a namespaced resource or a cluster-scoped resource. When there are references to namespace in the subject fields, they will be updated by the function.

This function can be used both declaratively and imperatively.

FunctionConfig #

There are 2 kinds of functionConfig supported by this function:

• ConfigMap
• A custom resource of kind SetNamespace

To use a ConfigMap as the functionConfig, the desired namespace must be specified in the data.namespace field.

To add a namespace staging to all resources, we use the following functionConfig:

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-config
data:
  namespace: staging

To use a SetNamespace custom resource as the functionConfig, the desired namespace must be specified in the namespace field. Sometimes you have resources (especially custom resources) that have namespace fields in fields other than the [defaults][commonnamespace], you can specify such label fields using additionalNamespaceFields. It will be used jointly with the [defaults][commonnamespace].

additionalNamespaceFields has following fields:

• group: Select the resources by API version group. Will select all groups if omitted.
• version: Select the resources by API version. Will select all versions if omitted.
• kind: Select the resources by resource kind. Will select all kinds if omitted.
• path: Specify the path to the field that the value needs to be updated. This field is required.
• create: If it’s set to true, the field specified will be created if it doesn’t exist. Otherwise, the function will only update the existing field.

To add namespace staging to all built-in resources and the path spec/selector/namespace in in MyKind resource, we use the following functionConfig:

apiVersion: fn.kpt.dev/v1alpha1
kind: SetNamespace
metadata:
name: my-config
additionalNamespaceFields:
  - path: spec/selector/namespace
    kind: MyKind
    version: v1
    group: example.com
    create: true