Override a specific key in a ConfigMap file

[akhayyat]

Given the following example ConfigMap:

apiVersion: v1
kind: ConfigMap
metadata:
  name: test-config
  namespace: default
data:
  hello: world
  file.conf: |-
    key1: value1
    key2: value2
    key3: value3

How can I override a single key's value in the yaml-formatted file.conf file, e.g. set key1 to new-value1, so that the patched ConfigMap becomes:

apiVersion: v1
kind: ConfigMap
metadata:
  name: test-config
  namespace: default
data:
  hello: world
  file.conf: |-
    key1: new-value1
    key2: value2
    key3: value3

[koba1t]

You can execute it using replacements in the following format.
Please use kustomize version v5.8.0 or later.

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- configmap.yaml

replacements:
- sourceValue: new-value1
  targets:
  - select:
      name: test-config
      namespace: default
    fieldPaths:
    - data.file\.conf.key1

[akhayyat]

Is kustomize 5.8.0 shipped with any version of kubectl or must I install it separately?

[koba1t]

kustomize v5.8.0 is not currently bundled with any kubectl, so you will need to install it.