k8S--05 K8s控制器类型

目录

• K8s控制器类型
  • 一、pod控制器
  • 二、ReplicaSet控制器
  • 三、Deployment资源配置清单
  • 四、Service控制器
  • 五、Ingress控制器介绍
    • 1.安装部署traefik
    • 2.创建traefik的web-ui的ingress规则
    • 3.ingress实验

K8s控制器类型

一、pod控制器

0.控制器作用
  pod类型的资源，删除pod后，不会重建
  替用户监视并保证相应的节点上始终有用户所期望的副本数量的pod在运行
  如果所运行的pod副本数超过了用户期望的，那么控制器就会删掉，直到和用户期望的一致 
  如果所运行的pod副本数低于用户期望的，那么控制器就会创建，直到和用户期望的一致 

1.常用控制器类型
  ReplicationController RC: 
  ReplicationSet RS:
    按用户期望的副本创建pod,并始终保持相应数量副本
  Deployment: 
    Deployment通过控制RS来保证POD始终保持相应的数量副本
    支持滚动更新，回滚,回滚默认保留10个版本
    提供声明式配置，支持动态修改
    管理无状态应用最理想的控制器
    node节点可能会运行0个或多个POD
  DeamonSet:
    一个节点只运行一个，必须是始终运行的状态
  StatefulSet:
    有状态应用
  Job:
    只运行一次的任务，不需要一直运行的任务
    确认任务完成才会退出
  Cronjob：
    周期性的任务

二、ReplicaSet控制器

1.编写RS控制器资源配置清单
cat >nginx-rs.yaml <<EOF
apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: nginx-rs
  namespace: default
spec:
  replicas: 2 
  selector: 
    matchLabels:
      app: nginx
  template:
    metadata:
      name: nginx-pod
      labels: 
        app: nginx
    spec:
      containers:
      - name: nginx-containers
        image: nginx:1.14.0
        imagePullPolicy: IfNotPresent
        ports:
        - name: http
          containerPort: 80
EOF

2.应用RS资源配置清单
kubectl create -f nginx-rs.yaml

3.查看RS资源
kubectl get rs 
kubectl get pod -o wide 

4.动态修改配置 扩容 收缩 升级
kubectl edit rs nginx
kubectl scale rs nginx --replicas=5

5.修改yaml文件应用修改
vim nginx-rs.yaml
kubectl apply -f nginx-rs.yaml

RS控制器示意图

三、Deployment资源配置清单

1.Deployment资源配置清单
cat >nginx-dp.yaml<<EOF
apiVersion: apps/v1
kind: Deployment 
metadata:
  name: nginx-deployment 
  namespace: default
spec:
  replicas: 2 
  selector: 
    matchLabels:
      app: nginx
  template:
    metadata:
      name: nginx-pod
      labels: 
        app: nginx
    spec:
      containers:
      - name: nginx-containers
        image: nginx:1.14.0
        imagePullPolicy: IfNotPresent
        ports:
        - name: http
          containerPort: 80
EOF

2.应用资源配置清单
kubectl create -f nginx-dp.yaml

3.查看
kubectl get pod -o wide
kubectl get deployments.apps
kubectl describe deployments.apps nginx-deployment

4.更新版本
方法1: 命令行根据资源配置清单修改镜像
kubectl set image -f nginx-dp.yaml nginx-containers=nginx:1.16.0

查看有没有更新
kubectl get pod 
kubectl describe deployments.apps nginx-deployment
kubectl describe pod nginx-deployment-7c596b4d95-6ztld

方法2: 命令行根据资源类型修改镜像
打开2个窗口：
第一个窗口监控pod状态
kubectl get pod -w

第二个窗口更新操作
kubectl set image deployment nginx-deployment nginx-containers=nginx:1.14.0

查看更新后的deployment信息
kubectl describe deployments.apps nginx-deployment 
----------------------------------------------------
  Normal  ScalingReplicaSet  14m                  deployment-controller  Scaled up replica set nginx-deployment-7c596b4d95 to 1
  Normal  ScalingReplicaSet  14m                  deployment-controller  Scaled down replica set nginx-deployment-9c74bb6c7 to 1
  Normal  ScalingReplicaSet  14m                  deployment-controller  Scaled up replica set nginx-deployment-7c596b4d95 to 2
  Normal  ScalingReplicaSet  13m                  deployment-controller  Scaled down replica set nginx-deployment-9c74bb6c7 to 0
  Normal  ScalingReplicaSet  8m30s                deployment-controller  Scaled up replica set nginx-deployment-9c74bb6c7 to 1
  Normal  ScalingReplicaSet  8m29s (x2 over 32m)  deployment-controller  Scaled up replica set nginx-deployment-9c74bb6c7 to 2
  Normal  ScalingReplicaSet  8m29s                deployment-controller  Scaled down replica set nginx-deployment-7c596b4d95 to 1
  Normal  ScalingReplicaSet  8m28s                deployment-controller  Scaled down replica set nginx-deployment-7c596b4d95 to 0
----------------------------------------------------
更新过程：
nginx-deployment-7c596b4d95-8z7kf   #老的版本
nginx-deployment-7c596b4d95-6ztld   #老的版本

nginx-deployment-9c74bb6c7-pgfxz    0/1     Pending	  
nginx-deployment-9c74bb6c7-pgfxz    0/1     Pending
nginx-deployment-9c74bb6c7-pgfxz    0/1     ContainerCreating  #拉取新版本镜像
nginx-deployment-9c74bb6c7-pgfxz    1/1     Running            #运行新POD
nginx-deployment-7c596b4d95-8z7kf   1/1     Terminating        #停止一个旧的POD
nginx-deployment-9c74bb6c7-h7mk2    0/1     Pending            
nginx-deployment-9c74bb6c7-h7mk2    0/1     Pending           
nginx-deployment-9c74bb6c7-h7mk2    0/1     ContainerCreating  #拉取新版本镜像
nginx-deployment-9c74bb6c7-h7mk2    1/1     Running            #运行新POD
nginx-deployment-7c596b4d95-6ztld   1/1     Terminating        #停止一个旧的POD
nginx-deployment-7c596b4d95-8z7kf   0/1     Terminating        #等待旧的POD结束
nginx-deployment-7c596b4d95-6ztld   0/1     Terminating        #等待旧的POD结束

查看滚动更新状态：
kubectl rollout status deployment nginx-deployment

5.回滚上一个版本
kubectl describe deployments.apps nginx-deployment 
kubectl rollout undo deployment nginx-deployment
kubectl describe deployments.apps nginx-deployment 

6.回滚到指定版本
v1 1.14.0
v2 1.15.0
v3 3.333.3
回滚到v1版本

创建第一版 1.14.0 
kubectl create -f nginx-dp.yaml  --record

更新第二版 1.15.0 
kubectl set image deployment nginx-deployment nginx-containers=nginx:1.15.0

更新第三版 1.99.0
kubectl set image deployment nginx-deployment nginx-containers=nginx:1.16.0

查看所有历史版本
kubectl rollout history deployment nginx-deployment

查看指定历史版本信息
kubectl rollout history deployment nginx-deployment --revision=1

回滚到指定版本
kubectl rollout undo deployment nginx-deployment --to-revision=1

7.扩缩容
kubectl scale deployment nginx-deployment --replicas=5
kubectl scale deployment nginx-deployment --replicas=2

四、Service控制器

Service控制器

0.Service控制器
  Sercice控制器和POD控制器没关系
  Sercice控制器可以选择由POD控制器创建的POD资源

1.三种IP
  NodeIP    :节点对外提供访问的IP 
  ClusterIP :用来动态发现和负载均衡POD的IP
  PodIP     :提供POD使用的IP

2.创建ClusterIP
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
  namespace: default
spec:
  selector: 
    app: nginx
  ports:
  - name: http
    port: 80 
    protocol: TCP
    targetPort: 80 
  type: ClusterIP 

3.查看ClusterIP
kubectl get svc

4.创建NodeIP资源配置清单
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
  namespace: default
spec:
  selector: 
    app: nginx
  ports:
  - name: http
    port: 8080	    #clusterIP的端口号
    protocol: TCP
    targetPort: 80  #POD暴露的端口
    nodePort: 30000 #NodeIP的端口号，也就是对外用户访问的端口号
  type: NodePort


5.查看创建的资源
kubectl get svc

五、Ingress控制器介绍

Ingress控制器介绍
1.没有ingress之前，pod对外提供服务只能通过NodeIP:NodePort的形式，但是这种形式有缺点，一个节点上的PORT不能重复利用。比如某个服务占用了80，那么其他服务就不能在用这个端口了。
2.NodePort是4层代理，不能解析7层的http，不能通过域名区分流量
3.为了解决这个问题，我们需要用到资源控制器叫Ingress，作用就是提供一个统一的访问入口。工作在7层
4.虽然我们可以使用nginx/haproxy来实现类似的效果，但是传统部署不能动态的发现我们新创建的资源，必须手动修改配置文件并重启。
5.适用于k8s的ingress控制器主流的有ingress-nginx和traefik
6.ingress-nginx == nginx + go --> deployment部署 
7.traefik有一个UI界面 

1.安装部署traefik

安装部署traefik
1.traefik_dp.yaml
kind: Deployment
apiVersion: apps/v1
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
  labels:
    k8s-app: traefik-ingress-lb
spec:
  replicas: 1
  selector:
    matchLabels:
      k8s-app: traefik-ingress-lb
  template:
    metadata:
      labels:
        k8s-app: traefik-ingress-lb
        name: traefik-ingress-lb
    spec:
      serviceAccountName: traefik-ingress-controller
      terminationGracePeriodSeconds: 60
      tolerations:
      - operator: "Exists"
      nodeSelector:
        kubernetes.io/hostname: node1 
      containers:
      - image: traefik:v1.7.17
        name: traefik-ingress-lb
        ports:
        - name: http
          containerPort: 80
          hostPort: 80
        - name: admin
          containerPort: 8080
        args:
        - --api
        - --kubernetes
        - --logLevel=INFO

2.traefik_rbac.yaml
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: traefik-ingress-controller
rules:
  - apiGroups:
      - ""
    resources:
      - services
      - endpoints
      - secrets
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - extensions
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: traefik-ingress-controller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: traefik-ingress-controller
subjects:
- kind: ServiceAccount
  name: traefik-ingress-controller
  namespace: kube-system

3.traefik_svc.yaml
kind: Service
apiVersion: v1
metadata:
  name: traefik-ingress-service
  namespace: kube-system
spec:
  selector:
    k8s-app: traefik-ingress-lb
  ports:
    - protocol: TCP
      port: 80
      name: web
    - protocol: TCP
      port: 8080
      name: admin
  type: NodePort

4.应用资源配置
kubectl create -f ./

5.查看并访问
kubectl -n kube-system get svc 

2.创建traefik的web-ui的ingress规则

创建traefik的web-ui的ingress规则
1.类比nginx:
upstream traefik-ui {
    server traefik-ingress-service:8080;
}

server {
    location / { 
        proxy_pass http://traefik-ui;
        include proxy_params;
    }
}


2.ingress写法:
apiVersion: extensions/v1beta1
kind: Ingress
metadata: 
  name: traefik-ui
  namespace: kube-system
spec:
  rules:
    - host: traefik.ui.com 
      http:
        paths:
          - path: /
            backend:
              serviceName: traefik-ingress-service 
              servicePort: 8080

3.访问测试：
traefik.ui.com

3.ingress实验

ingress实验
1.实验目标
未使用ingress之前只能通过IP+端口访问：
tomcat 8080
nginx  8090

使用ingress之后直接可以使用域名访问：
traefik.nginx.com:80   -->  nginx  8090
traefik.tomcat.com:80  -->  tomcat 8080

2.创建2个pod和svc
mysql-dp.yaml  
mysql-svc.yaml 
tomcat-dp.yaml  
tomcat-svc.yaml

nginx-dp.yaml  
nginx-svc-clusterip.yaml  

3.创建ingress控制器资源配置清单并应用
cat >nginx-ingress.yaml <<EOF
apiVersion: extensions/v1beta1
kind: Ingress
metadata: 
  name: traefik-nginx
  namespace: default 
spec:
  rules:
    - host: traefik.nginx.com 
      http:
        paths:
          - path: /
            backend:
              serviceName: nginx-service 
              servicePort: 80
EOF

cat >tomcat-ingress.yaml<<EOF
apiVersion: extensions/v1beta1
kind: Ingress
metadata: 
  name: traefik-tomcat
  namespace: default 
spec:
  rules:
    - host: traefik.tomcat.com 
      http:
        paths:
          - path: /
            backend:
              serviceName: myweb
              servicePort: 8080
EOF

kubectl apply -f nginx-ingress.yaml 
kubectl apply -f tomcat-ingress.yaml 

4.查看创建的资源
kubectl get svc
kubectl get ingresses
kubectl describe ingresses traefik-nginx
kubectl describe ingresses traefik-tomcat

5.访问测试
traefik.nginx.com
traefik.tomcat.com