Application Update Lifecycle

Pain Point

With containers based applications, frequent releases by multiple development teams make changes throughout the codebase. With this increasing number of moving parts, there is a likelihood that something could go wrong. To minimize these risks, container based applications need complete automation including CI and CD.

On one end, you need integration with a CI tool like Jenkins or CircleCI to push the latest updates to the code. Manually integrating CI with every Docker container in an application would be a tedious and nonproductive activity.

On the other end, developers need to use deployment strategies such as Canary and Blue Green for a controlled delivery process. In the case of Blue/Green Deployment, Kubernetes requires multiple deployments for each container and manually switching between these deployments by upscaling or downscaling each container. In the case of Canary deployment, developers are required to manually review and analyze application statistics and manually change the weight for each stage based on those statistics.

The following is an example snippet for a Blue/Green Deployment YAML. Here Tomcat v7 is deployed as Blue and Tomcat v8 is deployed as Green.

Complete Manifest files:

https://github.com/CloudplexPlatform/manifest-files/tree/master/kubernetes-manifest/blue-green-deployment-example

blue-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat-deployment-blue
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: tomcat
        role: blue
    spec:
      containers:
      - name: tomcat-container
        image: tomcat:7
        ports:
        - containerPort: 8080
        readinessProbe:
          httpGet:
            path: /
            port: 8080

svc.yaml

kind: Service
apiVersion: v1
metadata:
  name: tomcat-service
  labels:
    app: tomcat
    role: blue
    env: prod
spec:
  type: LoadBalancer
  selector:
    app: tomcat
    role: blue
  ports:
  - port: 80
    targetPort: 8080

green-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat-deployment-green
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: tomcat
        role: green
    spec:
      containers:
      - name: tomcat-container
        image: tomcat:8
        ports:
        - containerPort: 8080
        readinessProbe:
          httpGet:
            path: /
            port: 8080

In order to upgrade an existing container (for example v7 in blue deployment) to a newer version (say v8), first you need to put the blue deployment in inactive state, and then you have to assign green label to the newer version v8 ..then change the label in service to Green. This will shift all the traffic from Blue to Green. This process requires a lot of manual configuration changes from the developer at the time of rollout and rollback.

How CloudPlex addresses your pain

CloudPlex supports all major CI tools (e.g. Jenkins, CircleCI, Bitbucket etc. ). You just have to integrate webhook in your CI pipeline which is just a simple copy paste operation. Deploying Blue/Green, Canary, and Highlander version upgrades are super easy with Cloudplex. Developers can design multi-stage deployment pipelines and deployment strategy visually. All the configurations required are handled by the platform.

Configure blue/green

If the developer uses Blue/Green Deployment strategy, it requires very simple visual configuration. There is no intervention needed from the developer at rollout or rollback.