kubernetes 水平伸缩及yaml格式编写

Replication Controller：用来部署、升级Pod
Replica Set：下一代的Replication Controller
Deployment：可以更加方便的管理Pod和Replica Set
$ mkdir rc-demo
$ vim rc-demo.yaml
---
apiVersion: v1
kind: ReplicationController
metadata:
  name: rc-demo
  labels:
    app: rc
spec:
  replicas: 3
#  selecter:
#    app: rc
  template:
    metadata:
      labels:
        app: rc
    spec:
      containers:
      - name: nginx-demo
        image: nginx
        ports:
        - containerPort: 80
$ kubectl edit rc rc-demo
在里面可以修改副本集数量

滚动更新:
kubectl rolling-update rc-demo --image=nginx:1.7.9      ##(更新到1.7.9版本)

~~~~~RC不是实现一键回滚~~~~~

Deployment:

Deployment主要职责和RC一样都是保证Pod的数量和健康

RC的全部功能：Deployment具备上面描述的RC的全部功能
事件和状态查看：可以查看Deployment的升级详细进度和状态
回滚：当升级Pod的时候如果出现问题，可以使用回滚操作回滚到之前的任一版本
版本记录：每一次对Deployment的操作，都能够保存下来，这也是保证可以回滚到任一版本的基础
暂停和启动：对于每一次升级都能够随时暂停和启动

---
apiVersion: apps/v1beta1
kind: Deployment
metedata:
  name: nginx-deploy
  labels:
    app: nginx-demo
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80
template就相当于pod 只是省略apiVersion kind name
不指定name,自动生成name,避免重复

$ vim deploy-demo.yaml
---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: nginx-deploy
  labels:    
    app: nginx-demo
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80

滚动升级设置:
---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: nginx-deploy
  labels:    
    app: nginx-demo
spec:
  replicas: 3
  revisionHistoryLimit: 15
  minReadySeconds: 5
  stragety:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80

查询滚动更新状态:
kubectl rollout status deploy nginx-deploy
kubectl rollout pause deploy nginx-deploy  ##暂停滚动更新
kubectl rollout resume deploy nginx-deploy ##恢复滚动更新
kubectl rollout history deploy nginx-deploy #查看回滚历史版本
kubectl apply -f deploy-demo.yaml --record=true
rollout 历史版本跟rs有关,rs删除某一版本,rollout 历史版本中也会删除掉同一版本
kubectl rollout ando deploy nginx-deploy  ##回退上一版本最近的
 
kubectl rollout ando deploy nginx-deploy --to-revision=3 ##回退到指定版本

一.Pod水平自动伸缩(horizontal-pod-autoscaler)
1. kubectl autoscale命令来创建一个HPA资源对象
2. 可通过kube-controller-manager的标志--horizontal-pod-autoscaler-sync-period进行设置(轮询设置默认是30s)
3. HPA可以从heapster或者用户自定义的restclient端获取每一个的利用率
4.
    Heapster：仅支持CPU使用率
    自定义监控：我们到后面的监控的课程中再给大家讲解这部分的使用方法

安装 heapster:需要influxdb和grafana支持
1.https://github.com/kubernetes-retired/heapster/blob/v1.5.4/deploy/kube-config/influxdb/influxdb.yaml
 https://github.com/kubernetes-retired/heapster/blob/v1.5.4/deploy/kube-config/influxdb/heapster.yaml
 https://github.com/kubernetes-retired/heapster/blob/v1.5.4/deploy/kube-config/influxdb/grafana.yaml

2.查看heapster日志:
 kubectl logs -f heapster-5d4bf58946-hwqbz -n kube-system
### E0520 09:58:35.150249       1 reflector.go:190] k8s.io/heapster/metrics/util/util.go:30: Failed to list *v1.Node: nodes is forbidden: User "system:serviceaccount:kube-system:heapster" cannot list resource "nodes" in API group "" at the cluster scope

这个意思是heapster用户没有权限需要添加serviceaccount相对应的admin最高权限ClusterRole
集群规则绑定:ClusterRoleBinding

在heapster.yaml中的serviceaccount下面添加

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: heapster-admin
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: heapster
  namespace: kube-system
 
 
 
 
 
Hpa:
$ vim hap-demo.yaml
---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: hpa-demo
  labels:
    app: hpa
spec:
  replicas: 1
  revisionHistoryLimit: 15
  minReadySeconds: 5
  strategy:
    type: RollingUpdate
    rollingUpdate:
       maxSurge: 1
       maxUnavailable: 1
  template:
    metadata:
      labels:
        app: hpa
    spec:
      containers:
      - name: nginx
        image: nginx:1.9.7
        resources:
          requests:
            cpu: 100m
#          limit:
#            cpu: 200m
#            memory:
        ports:
        - containerPort: 80  
---
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  name: hpa-demo
  namespace: default
spec:
  maxReplicas: 10
  minReplicas: 1
  scaleTargetRef:
    apiVersion: extensions/v1beta1
    kind: Deployment
    name: hpa-demo
  targetCPUUtilizationPercentage: 5
 
$ kubectl autoscale deploy hpa-demo --min=1 --max=10 --cpu-percent=5

$ kubectl get hpa