CD 跟 CI 为啥不用一套？

app.yaml

kind: Application
spec:
  componnets:
    - ... # 微服务组件

  # policies are applied first and only once unless changed
  policies:
    - type: security
      properties:
        rbac: ...
        sso: ...
        audit: ...
        secretBackend: vault
    
    - type: deployment-insights
      properties:
        leadTime: enabled
        frequency: enabled
        mttr: enabled

    - type: gitops
      properties:
        source: git-repo-url
        branch: main
        path: config/
    
    - type: placement
      properties:
        clusters:
          - name: a
            replicas: "70%"
            traffic: "70%"
          - name: b
            replicas: "30%"
            traffic: "30%"

  # workflow is used to customize the control logic.
  # If workflow is specified, Vela won't apply resources in Components, but provide rendered resources for further actions.
  # workflow steps are executed in order.
  # Each step should have a "finish mark", e.g. in resource annotation `app.oam.dev/workflow-finish = succeed/fail`
  workflow:
  
    # blue-green rollout to prod
    - type: blue-gree-rollout
      properties:
        targetEnv: prod
        rolloutPlan:
          partition: "50%"

    # traffic shift
    - type: traffic-shift
      properties:
        targetEnv: prod
        rolloutPlan:
          partition: "50%"

    # promote/rollback
    - type: rollout-promotion
      propertie:
        manualApproval: true
        rollbackIfNotApproved: true

1. CD 有定制化需求，要跟公司的系统 (安全、灰度、服务治理、多集群、metrics) 深度集成。
2. CD 跟 CI 往往不是一个团队，要自己做一套。
3. CD 有复杂的发布 pipelines，比如在不同环境里轮流发布，类似于 Keptn 的 Multi-stage Delivery.