k8s Pod三种升级方式

哪几种发布方式

滚动更新

在这里插入图片描述

滚动更新通过设置MaxSurge和MaxUnavailable来规定可以有多少个额外的Pod和可以忍受多少个Pod无法提供服务（两个参数可以为0，但是不能同时为0），在整个更新的过程中都是平滑无缝衔接。

金丝雀发布

在这里插入图片描述

金丝雀发布，又称：灰度发布，在k8s中通过暂停滚动跟新来实现灰度发布。灰度发布，是将一个新的版本放入到整个集群中，当没有发现问题后再将其他Pod进行更新。

蓝绿发布

在这里插入图片描述

蓝绿发布相当于两个不相关的deployment，访问完全通过流量控制来达到目的，当在使用过程中出现问题，在通过流量切换切换回老的版本。

演示时间

滚动更新

  • 更新准备
kind: Deployment
metadata:
  name: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 5
  revisionHistoryLimit: 10
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 2
  template:
    metadata:
      labels:
        app: nginx
    spec:
      terminationGracePeriodSeconds: 60
      containers:
        - name: nginx
          image: nginx:1.11
          imagePullPolicy: IfNotPresent
          livenessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 30
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 15
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          ports:
          - containerPort: 80
            name: nginx

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  type: NodePort
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
  selector:
    app: nginx

[root@master k8s]# kubectl apply -f svc.yaml
[root@master k8s]# kubectl apply -f deployment.yaml
[root@master k8s]# kubectl get pod
NAME                    READY   STATUS    RESTARTS   AGE
nginx-7c66bcdf4-dtvcr   1/1     Running   0          43s
nginx-7c66bcdf4-qp7jb   1/1     Running   0          43s
nginx-7c66bcdf4-qxn8f   1/1     Running   0          43s
nginx-7c66bcdf4-rqckm   1/1     Running   0          43s
nginx-7c66bcdf4-tvk4f   1/1     Running   0          43s

修改yaml文件将nginx镜像版本修改为最新版本

kind: Deployment
metadata:
  name: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 5
  revisionHistoryLimit: 10
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 2
  template:
    metadata:
      labels:
        app: nginx
    spec:
      terminationGracePeriodSeconds: 60
      containers:
        - name: nginx
          image: nginx
          imagePullPolicy: IfNotPresent
          livenessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 30
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 15
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          ports:
          - containerPort: 80
            name: nginx

新开一个shell窗口执行

[root@master k8s]# kubectl get pod -w
NAME                    READY   STATUS    RESTARTS   AGE
nginx-7c66bcdf4-dtvcr   1/1     Running   0          3m28s
nginx-7c66bcdf4-qp7jb   1/1     Running   0          3m28s
nginx-7c66bcdf4-qxn8f   1/1     Running   0          3m28s
nginx-7c66bcdf4-rqckm   1/1     Running   0          3m28s
nginx-7c66bcdf4-tvk4f   1/1     Running   0          3m28s

开始滚动更新

[root@master k8s]# kubectl apply -f deployment.yaml

在这里插入图片描述
可以在新开窗口看到滚动更新过程

金丝雀发布

这里将已经更新到最新版本的nginx再通过金丝雀的方式还原回1.11版本

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 5
  revisionHistoryLimit: 10
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      terminationGracePeriodSeconds: 60
      containers:
        - name: nginx
          image: nginx:1.11
          imagePullPolicy: IfNotPresent
          livenessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 30
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 15
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          ports:
          - containerPort: 80
            name: nginx

保持新开窗口不要动，观察新开窗口

[root@master k8s]# kubectl apply -f deployment.yaml && kubectl rollout pause deployment/nginx
[root@master k8s]# kubectl get pod
NAME                     READY   STATUS    RESTARTS   AGE
nginx-6ff78767cc-97lg7   1/1     Running   0          5m59s
nginx-6ff78767cc-lhxx2   1/1     Running   0          5m59s
nginx-7c66bcdf4-fdt2h    1/1     Running   0          27s
nginx-7c66bcdf4-k8kvv    1/1     Running   0          27s
nginx-7c66bcdf4-mcwbr    1/1     Running   0          27s
nginx-7c66bcdf4-xfh9c    1/1     Running   0          27s

通过上面可以开出新起了三个Pod还有两个老的Pod，这时候可以利用curl命令多次访问服务来查看效果

[root@master k8s]# curl -I 192.168.0.201:31219
HTTP/1.1 200 OK
Server: nginx/1.11.13
Date: Fri, 04 Dec 2020 18:32:00 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 04 Apr 2017 15:01:57 GMT
Connection: keep-alive
ETag: "58e3b565-264"
Accept-Ranges: bytes

[root@master k8s]# curl -I 192.168.0.201:31219
HTTP/1.1 200 OK
Server: nginx/1.19.5
Date: Fri, 04 Dec 2020 18:32:05 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 24 Nov 2020 13:02:03 GMT
Connection: keep-alive
ETag: "5fbd044b-264"
Accept-Ranges: bytes

当测试没有问题时继续完成更新

[root@master k8s]# kubectl rollout resume deployment/nginx

更新完成后继续利用curl命令多次访问发现nginx版本已经全部更改

[root@master k8s]# curl -I 192.168.0.201:31219
HTTP/1.1 200 OK
Server: nginx/1.11.13
Date: Fri, 04 Dec 2020 18:34:27 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 04 Apr 2017 15:01:57 GMT
Connection: keep-alive
ETag: "58e3b565-264"
Accept-Ranges: bytes

[root@master k8s]# curl -I 192.168.0.201:31219
HTTP/1.1 200 OK
Server: nginx/1.11.13
Date: Fri, 04 Dec 2020 18:34:31 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 04 Apr 2017 15:01:57 GMT
Connection: keep-alive
ETag: "58e3b565-264"
Accept-Ranges: bytes

[root@master k8s]# curl -I 192.168.0.201:31219
HTTP/1.1 200 OK
Server: nginx/1.11.13
Date: Fri, 04 Dec 2020 18:34:33 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 04 Apr 2017 15:01:57 GMT
Connection: keep-alive
ETag: "58e3b565-264"
Accept-Ranges: bytes

蓝绿发布

准备两套yaml文件

  • nginx-v1.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-v1
spec:
  selector:
    matchLabels:
      app: nginx
      version: "1.11"
  replicas: 5
  revisionHistoryLimit: 10
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 3
  template:
    metadata:
      labels:
        app: nginx
        version: "1.11"
    spec:
      terminationGracePeriodSeconds: 60
      containers:
        - name: nginx-v1
          image: nginx:1.11
          imagePullPolicy: IfNotPresent
          livenessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 30
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 15
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          ports:
          - containerPort: 80
            name: nginx
  • nginx-v2.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-v2
spec:
  selector:
    matchLabels:
      app: nginx
      version: "1.19"
  replicas: 5
  revisionHistoryLimit: 10
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 3
  template:
    metadata:
      labels:
        app: nginx
        version: "1.19"
    spec:
      terminationGracePeriodSeconds: 60
      containers:
        - name: nginx-v2
          image: nginx
          imagePullPolicy: IfNotPresent
          livenessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 30
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /
              port: 80
              scheme: HTTP
            initialDelaySeconds: 15
            timeoutSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          ports:
          - containerPort: 80
            name: nginx

修改service的yaml文件

  • svc.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  type: NodePort
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
  selector:
    app: nginx
    version: "1.11"

将流量指向新版本的nginx上

  • 修改svc.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  type: NodePort
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
  selector:
    app: nginx
    version: "1.19"

通过curl命令可发现流量已经全部转到新版本的nginx上，此时将老版本的deployment删除即可

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