apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: rs-ft
  namespace: default
  labels:
    app: guestbook
    tier: frontend
spec:
  replicas: 3
  selector: # 在.spec.selector中定义的标签选择器必须能够匹配到spec.template.metadata.labels里定义的Pod标签
    matchLabels:
      tier1: frontend1
  template:
    metadata:
      labels:
        tier1: frontend1
    spec:
      containers:
      - name: samples-gb-frontend
        image: docker.io/yecc/gcr.io-google_samples-gb-frontend:v3
        imagePullPolicy: IfNotPresent
        ports: 
        - containerPort: 80

kubectl explain deploy.spec.strategy.rollingUpdate

   maxSurge   <string>
# 更新过程最多允许超出的指定的目标副本数有几个。
# 它有两种取值方式，第一种直接给定数量；第二种根据百分比，如最多可以超出20%，滚动更新开始时，马上scale up pod数为120%。然后逐渐的kill旧的，创建新的。
# Absolute number is calculated from percentage by rounding up. ==> 出现小数向上取整
   maxUnavailable <string>
# 最多允许几个不可用，数字或百分比。如果是30%，滚动更新开始，旧pod马上scale down到70%，然后随着新pod ready，旧pod再进一步scale down。
# Absolute number is calculated from percentage by rounding down. ==> 出现小数向下取整

replicas： 5
maxSurge: 25%         5*25%=1.25  ->5+2=7
maxUnavailable: 25%    5%25%=1.25  -> 5-1=4 #滚动更新时最少4个，最多7个

apiVersion: apps/v1
kind: Deployment
metadata:
  name: dep-myapp-blue
spec:
  replicas: 2
  selector:
    matchLabels:
      app: myapp
      version: v1
  template:
    metadata:
      labels:
        app: myapp
        version: v1
    spec:
      containers:
      - name: myapp
        image: janakiramm/myapp:v1
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 80

#查看rolling update的参数定义
kubectl explain deploy.spec.strategy
  #type：指定策略类型，支持两种策略
    #Recreate：在创建出新的Pod之前会先杀掉所有已存在的Pod
    #RollingUpdate：滚动更新，就是杀死一部分，就启动一部分，在更新过程中，存在两个版本Pod。（默认值）
  #rollingUpdate：当type为RollingUpdate时生效，用于为RollingUpdate设置参数，支持两个属性：
    #maxUnavailable：用来指定在升级过程中不可用Pod的最大数量，默认为25%。
    #maxSurge： 用来指定在升级过程中可以超过期望的Pod的最大数量，默认为25%。

#查看当前deploy的rolling update策略
kubectl describe deploy

kubectl rollout history deploy dep-myapp-blue 

deployment.apps/dep-myapp-blue 
REVISION  CHANGE-CAUSE
1         <none>
2         <none>

kubectl get rs #能看到两个rs，有一个旧版本的rs都是0.

kubectl rollout undo deploy dep-myapp-blue --to-revision=1 
# 也是滚动的方式，ready一个新的干掉一个旧的。

#通过kubectl patch改
kubectl patch deployment myapp-v1 -p '{"spec":{"strategy":{"rollingUpdate": {"maxSurge":1,"maxUnavailable":0}}}}'

#通过yaml文件改
kubectl explain deploy.spec.strategy
#yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: dep-myapp-blue
spec:
  replicas: 4
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: myapp
      version: v1
  template:
    metadata:
      labels:
        app: myapp
        version: v1
    spec:
      containers:
      - name: myapp
        image: janakiramm/myapp:v2
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 80
        ...

kubectl rollout pause deploy nginx
deployment.extensions/nginx paused

#部署deployment
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-v1
  namespace: blue-green
spec:
  replicas: 3
  selector:
   matchLabels:
    app: myapp
    version: v2
  template:
   metadata:
    labels:
     app: myapp
     version: v2
   spec:
    containers:
    - name: myapp
      image: janakiramm/myapp:v2
      imagePullPolicy: IfNotPresent
      ports:
      - containerPort: 80

kubectl create ns blue-green
ctr -n=k8s.io images import myapp-blue.tar.gz
ctr -n=k8s.io images import myapp-green.tar.gz

#创建前端service
apiVersion: v1
kind: Service
metadata:
  name: myapp-lan-lv
  namespace: blue-green
  labels:
    app: myapp
spec:
  type: NodePort
  ports:
  - port: 80
    nodePort: 30062
    name: http
  selector:
    app: myapp
    version: v2

#创建deployment
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-v2
  namespace: blue-green
spec:
  replicas: 3
  selector:
   matchLabels:
    app: myapp
    version: v1
  template:
   metadata:
    labels:
     app: myapp
     version: v1
   spec:
    containers:
    - name: myapp
      image: janakiramm/myapp:v1
      imagePullPolicy: IfNotPresent
      ports:
      - containerPort: 80

# 创建deployment
kubectl apply -f dep-green.yaml
# 更新镜像 && 暂停rollout
kubectl set image deployment myapp-v1 myapp=nginx:latest  -n blue-green && kubectl rollout pause deployment myapp-v1 -n blue-green
# 注：把myapp这个容器的镜像更新到nginx:latest版本 更新镜像之后，创建一个新的pod就立即暂停，这就是我们说的金丝雀发布；如果暂停几个小时之后没有问题，那么取消暂停，就会依次执行后面步骤，把所有pod都升级。
# 验证没问题，取消暂停更新，让deployment执行完滚动更新
kubectl rollout resume deployment myapp-v1 -n blue-green