kubectl/docs/book/pages/app_customization/bases_and_variants.md

{% panel style="info", title="TL;DR" %}

• Reuse Resource Config as Bases to kustomization.yaml's.
• Customize Base for different Environments.
• Reuse a Base across multiple Projects. {% endpanel %}

Bases and Variations

Motivation

It is common for users to deploy several Variants of the same Resource Config, or for different projects to reuse the same Resource Config. The Resource Config produced by a kustomization.yaml can be reused across multiple project using the kustomization.yaml as a Base.

Examples:

• a project may be deployed to dev, test, staging, canary and production environments, but with variants between the environments.
• a project may be deployed to different clusters that are tuned differently or running different versions of the project.

Referring to a Base

A project can add a Base by adding a path (relative to the kustomization.yaml) to base that points to a directory containing another kustomization.yaml file. This will automatically add and kustomize all of the Resources from the base project to the current project.

Bases can be:

• Relative paths from the kustomization.yaml - e.g. ../base
• Urls - e.g. github.com/kubernetes-sigs/kustomize/examples/multibases?ref=v1.0.6

{% method %} Example: Add a kustomization.yaml as a Base.

{% sample lang="yaml" %} Input: The kustomization.yaml file

# kustomization.yaml
bases:
- ../base

Base: kustomization.yaml and Resource Config

# ../base/kustomization.yaml
configMapGenerator:
- name: myJavaServerEnvVars
  literals:	
  - JAVA_HOME=/opt/java/jdk
  - JAVA_TOOL_OPTIONS=-agentlib:hprof
resources:
- deployment.yaml

# ../base/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
        volumeMounts:
        - mountPath: /etc/config
          name: config-volume
      volumes:
      - configMap:
          name: myJavaServerEnvVars
        name: config-volume

Applied: The Resource that is Applied to the cluster

# Unmodified Generated Base Resource
apiVersion: v1
kind: ConfigMap
metadata:
  name: myJavaServerEnvVars-k44mhd6h5f
data:
  JAVA_HOME: /opt/java/jdk
  JAVA_TOOL_OPTIONS: -agentlib:hprof
---
# Unmodified  Config Resource
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
        volumeMounts:
        - mountPath: /etc/config
          name: config-volume
      volumes:
      - configMap:
          name: myJavaServerEnvVars-k44mhd6h5f
        name: config-volume

{% endmethod %}

{% panel style="info", title="Bases in Bases" %} Bases themselves may also be Variants and have their own Bases. See Advanced Composition for more information. {% endpanel %}