kubevela.github.io/docs/end-user/rollout-app.md

title
Application Rollout

In this documentation, we will show how to use the rollout plan within application to do progressive rollout.

Overview

By default, when we update the spec of Application, KubeVela will update workload directly which relies on the underlying workload to provide availability.

KubeVela provides a unified progressive rollout mechanism, you can specify the spec.rolloutPlan in application to do so.

User Workflow

Here is the end to end user experience based on Deployment

1. Deploy application to the cluster

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
name: test-rolling
spec:
components:
  - name: metrics-provider
    type: worker
    properties:
      cmd:
        - ./podinfo
        - stress-cpu=1.0
      image: stefanprodan/podinfo:4.0.6
      port: 8080
rolloutPlan:
  rolloutStrategy: "IncreaseFirst"
  rolloutBatches:
    - replicas: 50%
    - replicas: 50%
  targetSize: 6

2. User can modify the application container command and apply

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
name: test-rolling
spec:
components:
  - name: metrics-provider
    type: worker
    properties:
      cmd:
        - ./podinfo
        - stress-cpu=2.0
      image: stefanprodan/podinfo:4.0.6
      port: 8080
rolloutPlan:
  rolloutStrategy: "IncreaseFirst"
  rolloutBatches:
    - replicas: 50%
    - replicas: 50%
  targetSize: 6

User can check the status of the Application and see the rollout completes, and the Application's status.rollout.rollingState becomes rolloutSucceed

Using AppRollout to adopt Application with rolloutPlan

Sometimes, we want to use AppRollout to adopt the Application Rollout, so we can use the AppRollout to specify more specific revision. The AppRollout can both rollout or revert the version of application.

If you want to let AppRollout adopt the Application with rolloutPlan, please add the annotations in application to tell AppRollout to adopt rollout, and clean the strategy in spec.rolloutPlan to avoid conflicts.

eg. to let AppRollout adopt the application above, you should update the application like below:

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: test-rolling
  annotations:
    "app.oam.dev/rolling-components": "metrics-provider"
    "app.oam.dev/rollout-template": "true"
spec:
  components:
    - name: metrics-provider
      type: worker
      properties:
        cmd:
          - ./podinfo
          - stress-cpu=2.0
        image: stefanprodan/podinfo:4.0.6
        port: 8080

Please refer to AppRollout to learn more details.