kustomize

• tool for customizing k8s configurations
• included in kubectl >= 1.14
• similar to Docker layers

Basic workflow

# create base manifests
mkdir k8s/base -p
vi k8s/base/service.yaml
vi k8s/base/deploy.yaml
vi k8s/base/kustomization.yaml

# add overlays to base
mkdir k8s/overlays/prod -p
vi k8s/overlays/prod/custom-env.yaml
vi k8s/overlays/prod/kustomization.yaml

Basic commands

# view resources
kubectl kustomize k8s/base
kubectl kustomize k8s/overlays/prod

# apply resource:
kubectl apply -k k8s/base
kubectl apply -k k8s/overlays/prod

# delete resource:
kubectl delete -k k8s/base
kubectl delete -k k8s/overlays/prod

Generating resources

configMapGenerator:

vi k8s/overlays/prod/application.properties
vi k8s/overlays/prod/kustomization.yaml # configMapGenerator

secretGenerator

vi k8s/overlays/prod/password.txt
vi k8s/overlays/prod/kustomization.yaml # secretGenerator

Cross-cutting fields

You can add fields into kustomization.yaml that will be applied to all resources, e.g.:

namespace: my-namespace
namePrefix: dev-
nameSuffix: "-001"
commonLabels:
  project: manhattan
commonAnnotations:
  oncallPager: 800-555-1212
resources:
- deployment.yaml

Resources:

• https://kubernetes.io/docs/tasks/manage-kubernetes-objects/kustomization/
• https://blog.stack-labs.com/code/kustomize-101/
• https://kubectl.docs.kubernetes.io/pages/reference/kustomize.html