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Helm Hook, Helm Test
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1. Helm Hook 기본 Flow

Concept helm hook for Helm.

1-1) Chart Template 생성

helm create mychart

templates 폴더 안에 불필요한 파일 삭제

rm -rf deployment.yaml  hpa.yaml  ingress.yaml  service.yaml  serviceaccount.yaml  tests/test-connection.yaml

1-2) pre-pod 생성

vi pre-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: pre-pod
  annotations:
    helm.sh/hook: pre-upgrade
spec:
  restartPolicy: Never
  containers:
  - name: container
    image: kubetm/init
    command: ["sh", "-c", "echo 'start'; sleep 10; echo 'done'"]

1-3) Deployment 생성

vi deployment.yaml

apiVersion: v1
kind: Service
metadata:
  name: svc
spec:
  selector:
    type: app
  ports:
  - port: 80
    targetPort: 8080
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment
spec:
  selector:
    matchLabels:
      type: app
  replicas: 1
  template:
    metadata:
      labels:
        type: app
      annotations:
        rollme: {{ randAlphaNum 5 | quote }}
    spec:
      initContainers:
      - name: init-myservice
        image: kubetm/app
        command: ["sh", "-c", "echo 'start'; sleep 10; echo 'done'"]
      containers:
      - name: container
        image: kubetm/app

1-4) post-pod 생성

vi post-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: post-pod
  annotations:
    helm.sh/hook: post-upgrade
spec:
  restartPolicy: Never
  containers:
  - name: container
    image: kubetm/init
    command: ["sh", "-c", "echo 'start'; sleep 10; echo 'done'"]

1-5) test-pod 생성

mkdir tests
vi test-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: test-pod
  annotations:
    helm.sh/hook: test
spec:
  restartPolicy: Never
  containers:
  - name: container
    image: kubetm/init
    command: ["sh", "-c", "echo 'start'; curl svc/hostname; echo 'done'"]

1-6) crd-pod.yaml 내용 업데이트

mkdir crds
vi crd-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: crd-pod
  annotations:
    helm.sh/hook: pre-upgrade
spec:
  restartPolicy: Never
  containers:
  - name: container
    image: kubetm/init
    command: ["sh", "-c", "echo 'start'; sleep 10; echo 'done'"]

1-7) Install 명령

helm upgrade mychart ./../ -n nm-1 --create-namespace --install
kubectl get pods -n nm-1

1-8) Upgrade 명령

helm upgrade mychart ./../ -n nm-1 --create-namespace --install
kubectl get pods -n nm-1

1-9) Test 명령

helm test mychart -n nm-1
kubectl get pods -n nm-1


2. hook-weight

hook-weight for Helm.

2-1) Chart Template 생성

helm create mychart2

templates 폴더 안에 불필요한 파일 삭제

rm -rf deployment.yaml  hpa.yaml  ingress.yaml  service.yaml  serviceaccount.yaml  tests

2-2) pre-pod1 생성

vi pre-pod1.yaml

apiVersion: v1
kind: Pod
metadata:
  name: pre-pod1
  annotations:
    helm.sh/hook: pre-install
    helm.sh/weight: "-1"
spec:
  restartPolicy: Never
  containers:
  - name: container
    image: kubetm/init
    command: ["sh", "-c", "echo 'start'; sleep 10; echo 'done'"]

2-3) pre-pod2 생성

vi pre-pod2.yaml

apiVersion: v1
kind: Pod
metadata:
  name: pre-pod2
  annotations:
    helm.sh/hook: pre-install
spec:
  restartPolicy: Never
  containers:
  - name: container
    image: kubetm/init
    command: ["sh", "-c", "echo 'start'; sleep 10; echo 'done'"]

2-4) pre-pod3 생성

vi pre-pod3.yaml

apiVersion: v1
kind: Pod
metadata:
  name: pre-pod3
  annotations:
    helm.sh/hook: pre-install
    helm.sh/hook-weight: "1"
spec:
  restartPolicy: Never
  containers:
  - name: container
    image: kubetm/init
    command: ["sh", "-c", "echo 'start'; sleep 10; echo 'done'"]

2-5) Deployment 생성

vi deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment
spec:
  selector:
    matchLabels:
      type: init
  replicas: 1
  template:
    metadata:
      labels:
        type: init
      annotations:
        rollme: {{ randAlphaNum 5 | quote }}
    spec:
      containers:
      - name: container
        image: kubetm/init

2-6) Helm Install 실행

helm upgrade mychart2 ./../ -n nm-2 --create-namespace --install
kubectl get pods -n nm-2


3. hook-delete-policy

hook-delete-policy for Helm.

3-1) 이전 실습 리소스 제거

rm -rf pre-pod2.yaml pre-pod3.yaml
kubectl delete pods -n nm-2 pre-hook-pod2 pre-hook-pod3
kubectl get pods -n nm-2

3-2) pre-pod1

vi pre-pod1.yaml

apiVersion: v1
kind: Pod
metadata:
  name: pre-pod1
  annotations:
    helm.sh/hook: pre-upgrade
#   helm.sh/hook-delete-policy: hook-succeeded
#   helm.sh/hook-delete-policy: hook-failed
#   helm.sh/hook-delete-policy: before-hook-creation
spec:
  restartPolicy: Never
  containers:
  - name: container
    image: kubetm/init
    command: ["sh", "-c", "echo 'start'; sleep 10; echo 'done'"]

3-3) Helm Install 실행

helm upgrade mychart2 ./../ -n nm-2 --create-namespace --install
kubectl delete pods -n nm-2 pre-hook-pod1
kubectl get pods -n nm-2


Referenece

Helm