基于Kubernetes实现滚动部署、蓝绿部署以及金丝雀部署

1. 部署策略对比

分别对滚动部署、蓝绿部署和金丝雀部署进行对比

滚动部署：应用的新版本逐步替换旧版本。实际的部署发生在一段时间内。在此期间，新旧版本会共存，而不会影响功能和用户体验。这个过程可以更轻易的回滚和旧组件不兼容的任何新组件。

部署策略对比：滚动部署、蓝绿部署以及金丝雀部署

蓝绿部署：应用的新版本部署在绿色版本环境中，进行功能和性能测试。一旦测试通过，应用的流量从蓝色版本路由到绿色版本。然后绿色版本变成新的生产环境。在这个方法中，两个相同的生产环境并行工作。

部署策略对比：滚动部署、蓝绿部署以及金丝雀部署

金丝雀部署：采用金丝雀部署，你可以在生产环境的基础设施中小范围的部署新的应用代码。一旦应用签署发布，只有少数用户被路由到它。最大限度的降低影响。如果没有错误发生，新版本可以逐渐推广到整个基础设施。以前旷工开矿下矿洞前，先会放一只金丝雀进去探是否有有毒气体，看金丝雀能否活下来，金丝雀发布由此得名。下图示范了金丝雀部署：

部署策略对比：滚动部署、蓝绿部署以及金丝雀部署

金丝雀部署包括将生产流量从版本A逐渐转移到版本B。通常，流量是根据权重分配的。例如，90％的请求发送到版本A，10％的请求发送到版本B。

2. 使用Kubernetes实现金丝雀部署

主要步骤：
1.部署v1版本的应用，此时service访问的都是v1版本的服务
2.部署v2版本，数量为x/10，同时缩小v1版本的数量x/10，此时有x/10的流量到v2版本的服务
3.逐步缩小v1，扩大v2，最终v2版本替换全部的v1

2.1 搭建模拟的服务

app-v1.yaml : https://github.com/ContainerSolutions/k8s-deployment-strategies/blob/master/canary/native/app-v1.yaml

apiVersion: v1
kind: Service
metadata:
  name: my-app
  labels:
    app: my-app
spec:
  type: NodePort
  ports:
  - name: http
    port: 80
    targetPort: http
  selector:
    app: my-app
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app-v1
  labels:
    app: my-app
spec:
  replicas: 10
  selector:
    matchLabels:
      app: my-app
      version: v1.0.0
  template:
    metadata:
      labels:
        app: my-app
        version: v1.0.0
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "9101"
    spec:
      containers:
      - name: my-app
        image: containersol/k8s-deployment-strategies
        ports:
        - name: http
          containerPort: 8080
        - name: probe
          containerPort: 8086
        env:
        - name: VERSION
          value: v1.0.0
        livenessProbe:
          httpGet:
            path: /live
            port: probe
          initialDelaySeconds: 5
          periodSeconds: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: probe
          periodSeconds: 5

$kubectl apply -f app-v1.yaml
service/my-app created
deployment.apps/my-app-v1 created

$kubectl get service my-app
NAME     TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
my-app   NodePort   10.98.198.198           80:30969/TCP   23m

$curl 10.98.198.198:80
Host: my-app-v1-c9b7f9985-5qvz4, Version: v1.0.0

2.2 应用使用金丝雀部署方式来升级

接下来，我们对my-app-v1升级到my-app-v2：

app-v2.yaml : https://github.com/ContainerSolutions/k8s-deployment-strategies/blob/master/canary/native/app-v2.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app-v2
  labels:
    app: my-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-app
      version: v2.0.0
  template:
    metadata:
      labels:
        app: my-app
        version: v2.0.0
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "9101"
    spec:
      containers:
      - name: my-app
        image: containersol/k8s-deployment-strategies
        ports:
        - name: http
          containerPort: 8080
        - name: probe
          containerPort: 8086
        env:
        - name: VERSION
          value: v2.0.0
        livenessProbe:
          httpGet:
            path: /live
            port: probe
          initialDelaySeconds: 5
          periodSeconds: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: probe
          periodSeconds: 5

开启watch来监控pod和deployment的变化

$kubectl get --watch deployment
$kubectl get --watch pod

升级

$kubectl apply -f app-v2.yaml
deployment.apps/my-app-v2 created

此时可以看到，my-app-v2启动了1个

$kubectl get --watch deployment
NAME        READY   UP-TO-DATE   AVAILABLE   AGE
my-app-v1   10/10   10           10          45m
my-app-v2   1/1     1            1           46s

$kubectl scale --replicas=9 deploy my-app-v1
deployment.apps/my-app-v1 scaled

$kubectl get deployments
NAME        READY   UP-TO-DATE   AVAILABLE   AGE
my-app-v1   9/9     9            9           47m
my-app-v2   1/1     1            1           2m48s

此时，我们将my-app-v1 缩小到9个，这样通过service的负载均衡，my-app-v2会承接到%10（1/20）的流量

$service=10.98.198.198:80
$while sleep 0.1; do curl "$service"; done
Host: my-app-v1-c9b7f9985-mqnmr, Version: v1.0.0
Host: my-app-v1-c9b7f9985-bl4g7, Version: v1.0.0
Host: my-app-v1-c9b7f9985-rmng9, Version: v1.0.0
Host: my-app-v1-c9b7f9985-mz9hc, Version: v1.0.0
Host: my-app-v1-c9b7f9985-bl4g7, Version: v1.0.0
Host: my-app-v1-c9b7f9985-mz9hc, Version: v1.0.0
Host: my-app-v1-c9b7f9985-mm6fp, Version: v1.0.0
Host: my-app-v2-77fc8c9499-m6n9j, Version: v2.0.0
Host: my-app-v1-c9b7f9985-l69pf, Version: v1.0.0
Host: my-app-v1-c9b7f9985-mqnmr, Version: v1.0.0
Host: my-app-v1-c9b7f9985-mz9hc, Version: v1.0.0
Host: my-app-v1-c9b7f9985-62zb4, Version: v1.0.0

验证通过后，我们逐步将my-app-v2扩容到10个，将my-app-v1缩小到0个

$kubectl scale --replicas=10 deploy my-app-v2
$kubectl delete deploy my-app-v1

再次验证服务，会发现my-app-v2承接了所有流量:

$while sleep 0.1; do curl "$service"; done

测试完成清理数据

$kubectl delete all -l app=my-app

3. 使用Kubernetes实现蓝绿部署

主要步骤：
1.部署v1版本，此时service访问的都是v1版本的服务
2.部署v2版本，直到部署完成
3.将service的流量从v1版本切换到v2版本
4.销毁v1

首先，通过如下命令监控pod的实时状态

$watch kubectl get pod

3.1 搭建模拟的服务

app-v1.yaml:https://github.com/ContainerSolutions/k8s-deployment-strategies/blob/master/blue-green/single-service/app-v1.yaml

apiVersion: v1
kind: Service
metadata:
  name: my-app
  labels:
    app: my-app
spec:
  type: NodePort
  ports:
  - name: http
    port: 80
    targetPort: http

  # Note here that we match both the app and the version
  selector:
    app: my-app
    version: v1.0.0
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app-v1
  labels:
    app: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
      version: v1.0.0
  template:
    metadata:
      labels:
        app: my-app
        version: v1.0.0
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "9101"
    spec:
      containers:
      - name: my-app
        image: containersol/k8s-deployment-strategies
        ports:
        - name: http
          containerPort: 8080
        - name: probe
          containerPort: 8086
        env:
        - name: VERSION
          value: v1.0.0
        livenessProbe:
          httpGet:
            path: /live
            port: probe
          initialDelaySeconds: 5
          periodSeconds: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: probe
          periodSeconds: 5

部署服务和v1版本

$kubectl apply -f app-v1.yaml
service/my-app created
deployment.apps/my-app-v1 created

$kubectl get service
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1                443/TCP        14d
my-app       NodePort    10.111.231.242           80:31540/TCP   18s

$while sleep 0.1;do curl 10.111.231.242:80;done
Host: my-app-v1-c9b7f9985-wqpf5, Version: v1.0.0
Host: my-app-v1-c9b7f9985-wqpf5, Version: v1.0.0
Host: my-app-v1-c9b7f9985-gnhr4, Version: v1.0.0

3.2 部署v2版本

app-v2.yaml:https://github.com/ContainerSolutions/k8s-deployment-strategies/blob/master/blue-green/single-service/app-v2.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app-v2
  labels:
    app: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
      version: v2.0.0
  template:
    metadata:
      labels:
        app: my-app
        version: v2.0.0
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "9101"
    spec:
      containers:
      - name: my-app
        image: containersol/k8s-deployment-strategies
        ports:
        - name: http
          containerPort: 8080
        - name: probe
          containerPort: 8086
        env:
        - name: VERSION
          value: v2.0.0
        livenessProbe:
          httpGet:
            path: /live
            port: probe
          initialDelaySeconds: 5
          periodSeconds: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: probe
          periodSeconds: 5

部署完成后，我们可以看到，总共个部署了两个版本的deployment。有3个pod是v1，另外3个是v2的。而当前service访问的都是v1版本的服务

image.png

接下来，就是要将服务的流量切到v2

$kubectl patch service my-app -p '{"spec":{"selector":{"version":"v2.0.0"}}}'

此时可以看到，服务的流量都到了v2

image.png

验证没问题后，我们把v1删除

$kubectl delete deploy my-app-v1

若有问题，可以回滚

$kubectl patch service my-app -p '{"spec":{"selector":{"version":"v1.0.0"}}}'

4 使用Kubernetes实现滚动部署

主要步骤：
1.部署v1版本，此时service访问的都是v1版本的服务
2.设置v2版本，且更新策略为滚动更新
3.部署v2版本

4.1 搭建模拟的服务

app-v1.yaml: https://github.com/ContainerSolutions/k8s-deployment-strategies/blob/master/ramped/app-v1.yaml

apiVersion: v1
kind: Service
metadata:
  name: my-app
  labels:
    app: my-app
spec:
  type: NodePort
  ports:
  - name: http
    port: 80
    targetPort: http
  selector:
    app: my-app
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
  labels:
    app: my-app
spec:
  replicas: 10
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
        version: v1.0.0
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "9101"
    spec:
      containers:
      - name: my-app
        image: containersol/k8s-deployment-strategies
        ports:
        - name: http
          containerPort: 8080
        - name: probe
          containerPort: 8086
        env:
        - name: VERSION
          value: v1.0.0
        livenessProbe:
          httpGet:
            path: /live
            port: probe
          initialDelaySeconds: 5
          periodSeconds: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: probe
          periodSeconds: 5

部署app-v1.yaml

$kubectl apply -f app-v1.yaml
service/my-app created
deployment.apps/my-app created

$kubectl get service
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1              443/TCP        14d
my-app       NodePort    10.100.43.22           80:32725/TCP   45s

$curl 10.100.43.22:80
Host: my-app-c9b7f9985-ph2fz, Version: v1.0.0

4.2 接下来准备进行滚动升级

通过如下命令监控pod的变化

$watch kubectl get pod

app-v2.yaml : https://github.com/ContainerSolutions/k8s-deployment-strategies/blob/master/ramped/app-v2.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
  labels:
    app: my-app
spec:
  replicas: 10

  # Here we define the rolling update strategy
  # - maxSurge define how many pod we can add at a time
  # - maxUnavailable define how many pod can be unavailable
  #   during the rolling update
  #
  # Setting maxUnavailable to 0 would make sure we have the appropriate
  # capacity during the rolling update.
  # You can also use percentage based value instead of integer.
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0

  # The selector field tell the deployment which pod to update with
  # the new version. This field is optional, but if you have labels
  # uniquely defined for the pod, in this case the "version" label,
  # then we need to redefine the matchLabels and eliminate the version
  # field from there.
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
        version: v2.0.0
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "9101"
    spec:
      containers:
      - name: my-app
        image: containersol/k8s-deployment-strategies
        ports:
        - name: http
          containerPort: 8080
        - name: probe
          containerPort: 8086
        env:
        - name: VERSION
          value: v2.0.0
        livenessProbe:
          httpGet:
            path: /live
            port: probe
          initialDelaySeconds: 5
          periodSeconds: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: probe

          # Intial delay is set to a high value to have a better
          # visibility of the ramped deployment
          initialDelaySeconds: 15
          periodSeconds: 5

开始升级

$kubectl apply -f app-v2.yaml
deployment.apps/my-app configured

同时可以看到pod正在被逐步替换

image.png

在逐步替换的过程中，为了验证流量，可以随时暂停升级，暂停恢复命令如下

$kubectl rollout pause deploy my-app
deployment.apps/my-app paused

$kubectl rollout resume deploy my-app
deployment.apps/my-app resumed

基于Kubernetes实现滚动部署、蓝绿部署以及金丝雀部署

1. 部署策略对比

2. 使用Kubernetes实现金丝雀部署

2.1 搭建模拟的服务

2.2 应用使用金丝雀部署方式来升级

3. 使用Kubernetes实现蓝绿部署

3.1 搭建模拟的服务

3.2 部署v2版本

4 使用Kubernetes实现滚动部署

4.1 搭建模拟的服务

4.2 接下来准备进行滚动升级

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