Kustomize — rise and shine

I try to help you here with kustomize issues I had and how got along with them. You can follow for more updates in near future

by https://ordina-jworks.github.io/

Basic Preparations

$ brew install kustomize
[...]
$ mkdir -p myrepo/base myrepo/sonarqube/
$ cd myrepo
$ kustomize init

Case 1: Preparation

Replace your ingress hostname with kustomize configMapGenerator + vars

base/sonarqube/ingress.yaml

• Define your variables like $(SONARQUBE_EXTERNAL_URL) which should be replaced later on by kustomize

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: sonarqube-ingress
  labels:
    app.kubernetes.io/name: sonarqube
    app.kubernetes.io/instance: default
    app.kubernetes.io/version: default
  annotations: {}
  namespace: default
spec:
# TLS -> can be ignored for now
#  tls:
#  - hosts:
#    - $(SONARQUBE_EXTERNAL_URL)
#    secretName: testsecret-tls
  rules:
  - host: $(SONARQUBE_EXTERNAL_URL)
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: $(SONARQUBE_SERVICE)
            port:
              number: 9000

base/sonarqube/ingress.yaml

apiVersion: v1
kind: Service
metadata:
  name: sonarqube-svc
  namespace: default
  labels:
    app.kubernetes.io/name: sonarqube
    app.kubernetes.io/component: java
  annotations: {}
spec:
  selector:
    app.kubernetes.io/name: sonarqube
  ports:
  - port: 9000
    protocol: TCP
    targetPort: 9000

kustomize.yaml

• define the resources we’d like to import from base
• describe vars you’d like to make usable in your kustomize yamls
  NOTE: kustomize searches for $(<MyVarName e.g.: SONARQUBE_SERVICE>)
• The configMapGenerator will provide us with our literals as parameters which we then can reference from vars or other places

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- base/sonarqube/service.yaml
- base/sonarqube/ingress.yaml
#
# VARIABLES
#
vars:
- name: SONARQUBE_SERVICE
  objref:
    apiVersion: v1
    kind: Service
    name: sonarqube-svc
  fieldref:
    fieldpath: metadata.name
- name: SONARQUBE_EXTERNAL_URL
  objref:
    apiVersion: v1
    kind: ConfigMap
    name: test
  fieldref:
    fieldpath: data.SONARQUBE_EXTERNAL_URL
#
# CONFIGMAP-GENERATOR
#
generatorOptions:
  disableNameSuffixHash: true
configMapGenerator:
- name: test
  literals:
  - SONARQUBE_EXTERNAL_URL=sonarqube.apps.example.com
  - POSTGRES_PORT=5432
  - SONARQUBE_PORT=9000
#
# ADDITIONAL-CONFIG
#
configurations:
- sonarqube/lookup.yaml

sonarqube/lookup.yaml

• Here we store the “paths” where kustomize should look after variabels which should be replaced

varReference:
- kind: Ingress
  path: spec/rules[]/http/paths[]/backend/service/name
- kind: Ingress
  path: spec/rules[]/hosts
- kind: Ingress
  path: spec/tls[]/hosts[]

Case 1: Rendering/Building

• If you followed carefully then your result should equal the following

$ kustomize build --load_restrictor none
apiVersion: v1
data:
  POSTGRES_PORT: "5432"
  SONARQUBE_EXTERNAL_URL: sonarqube.apps.example.com
  SONARQUBE_PORT: "9000"
kind: ConfigMap
metadata:
  labels:
    app.kubernetes.io/managed-by: kustomize
    app.kubernetes.io/part-of: sonarqube
  name: test
  namespace: default
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app.kubernetes.io/component: java
    app.kubernetes.io/managed-by: kustomize
    app.kubernetes.io/name: sonarqube
    app.kubernetes.io/part-of: sonarqube
  name: sonarqube-svc
  namespace: default
spec:
  ports:
  - port: 9000
    protocol: TCP
    targetPort: 9000
  selector:
    app.kubernetes.io/managed-by: kustomize
    app.kubernetes.io/name: sonarqube
    app.kubernetes.io/part-of: sonarqube
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  labels:
    app.kubernetes.io/instance: default
    app.kubernetes.io/managed-by: kustomize
    app.kubernetes.io/name: sonarqube
    app.kubernetes.io/part-of: sonarqube
    app.kubernetes.io/version: default
  name: sonarqube-ingress
  namespace: default
spec:
  rules:
  - host: sonarqube.apps.example.com
    http:
      paths:
      - backend:
          service:
            name: sonarqube-svc
            port:
              number: 9000
        path: /
        pathType: Prefix

Stay tuned for more!

Cheers!

Sources

• https://github.com/kubernetes-sigs/kustomize
• https://kustomize.io/
• https://kubectl.docs.kubernetes.io/references/kustomize/