Kubernetes/kustomize

kustomize

kubectl kustomize | Kubernetes
https://kubernetes.io/docs/reference/kubectl/generated/kubectl_kustomize/

Generate manifest

kubectl kustomize DIR [flags]
# or
kustomize build DIR [flags]

# then do a " > out.yaml " to save

Install manifest:

kubectl apply -f out.yaml

or Install manifest directly:

# Apply resources from a directory containing kustomization.yaml - e.g. dir/kustomization.yaml
kubectl apply -k DIR

or string kustomize:

kustomize build DIR [flags] | kubectl apply -f -

# eg. that uses ../../files/tls.key
kustomize build --load-restrictor=LoadRestrictionsNone patches/ssl-patch

Installation

Installation

Kustomize Installation
https://kubectl.docs.kubernetes.io/installation/kustomize/

Via Go source:

git clone git@github.com:kubernetes-sigs/kustomize.git
cd kustomize
make kustomize
# git checkout kustomize/v5.0.0
~/go/bin/kustomize version

Via binary:

curl -s "https://raw.githubusercontent.com/kubernetes-sigs/kustomize/master/hack/install_kustomize.sh"  | bash
mv kustomize /usr/local/bin/kustomize

Version:

kustomize version
 v5.4.2

Kustomize

Kustomize - Kubernetes native configuration management
https://kustomize.io/

Kustomize introduces a template-free way to customize application configuration that simplifies the use of off-the-shelf applications. Now, built into kubectl as apply -k.

Hello World

Hello World
https://github.com/kubernetes-sigs/kustomize/blob/master/examples/helloWorld/kustomization.yaml

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
metadata:
  name: arbitrary

# Example configuration for the webserver
# at https://github.com/monopole/hello
commonLabels:
  app: hello

resources:
- deployment.yaml
- service.yaml
- configMap.yaml

Envs

cat <<'EOF' >$DEMO_HOME/foo.env
ROUTER_PASSWORD=admin
DB_PASSWORD=iloveyou
EOF

cat <<'EOF' >$DEMO_HOME/kustomization.yaml
secretGenerator:
- name: mysecrets
  envs:
  - foo.env
  files:
  - longsecret.txt
  literals:
  - FRUIT=apple
  - VEGETABLE=carrot
EOF

ref: [1]

Patch

Ingress replace Example:

Sample project structure:

|-- base
    ingress.yaml
    deployment.yaml
    kustomization.yaml
|-- overlays
    |-- prod
        ingress-patch.yaml
        kustomization.yaml
    |-- dev
        ingress-patch.yaml
        kustomization.yaml

ingress:

...
spec:
  ingressClassName: alb
  rules:
  - host: app.devopscons.com #it will be dev-app.devopscons.com
...

ingress-patch.yaml

- op: replace #action 
  path: /spec/rules/0/host #resouirce we want to change
  value: dev-app.devopscons.com #value we want to use for patching 

add to kustomization.yaml:

patches:
 - target:
      group: networking.k8s.io
      version: v1
      kind: Ingress
      name: ingress
   path: ingress-patch.yaml

---

Resouce Example:

some-patch.yaml

- op: add #action
  path: "/spec/template/spec/nodeSelector" #resouirce we want to change
  value:             #value we want to use for patching
    env: prod
    type: spot
    version: "3"

and add to kuszomization patch section like above.

other references:

• https://kubernetes.io/docs/tasks/manage-kubernetes-objects/kustomization/#customizing