Dry Run for Debugging

Dry run will help you to understand what are the real resources which will to be expanded and deployed to the Kubernetes cluster. In other words, it will mock to run the same logic as KubeVela’s controller and output the results locally.

For example, let’s dry-run the following application:

  1. # app.yaml
  2. apiVersion: core.oam.dev/v1beta1
  3. kind: Application
  4. metadata:
  5.   name: vela-app
  6. spec:
  7.   components:
  8.     - name: express-server
  9.       type: webservice
  10.       properties:
  11.         image: oamdev/hello-world
  12.         port: 8000
  13.       traits:
  14.         - type: ingress
  15.           properties:
  16.             domain: testsvc.example.com
  17.             http:
  18.               "/": 8000
  1. vela dry-run -f app.yaml
  2. ---
  3. # Application(vela-app) -- Comopnent(express-server)
  4. ---
  6. apiVersion: apps/v1
  7. kind: Deployment
  8. metadata:
  9.   labels:
  10.     app.oam.dev/appRevision: ""
  11.     app.oam.dev/component: express-server
  12.     app.oam.dev/name: vela-app
  13.     workload.oam.dev/type: webservice
  14. spec:
  15.   selector:
  16.     matchLabels:
  17.       app.oam.dev/component: express-server
  18.   template:
  19.     metadata:
  20.       labels:
  21.         app.oam.dev/component: express-server
  22.     spec:
  23.       containers:
  24.       - image: oamdev/hello-world
  25.         name: express-server
  26.         ports:
  27.         - containerPort: 8000
  29. ---
  30. apiVersion: v1
  31. kind: Service
  32. metadata:
  33.   labels:
  34.     app.oam.dev/appRevision: ""
  35.     app.oam.dev/component: express-server
  36.     app.oam.dev/name: vela-app
  37.     trait.oam.dev/resource: service
  38.     trait.oam.dev/type: ingress
  39.   name: express-server
  40. spec:
  41.   ports:
  42.   - port: 8000
  43.     targetPort: 8000
  44.   selector:
  45.     app.oam.dev/component: express-server
  47. ---
  48. apiVersion: networking.k8s.io/v1beta1
  49. kind: Ingress
  50. metadata:
  51.   labels:
  52.     app.oam.dev/appRevision: ""
  53.     app.oam.dev/component: express-server
  54.     app.oam.dev/name: vela-app
  55.     trait.oam.dev/resource: ingress
  56.     trait.oam.dev/type: ingress
  57.   name: express-server
  58. spec:
  59.   rules:
  60.   - host: testsvc.example.com
  61.     http:
  62.       paths:
  63.       - backend:
  64.           serviceName: express-server
  65.           servicePort: 8000
  66.         path: /
  68. ---

In this example, the definitions(webservice and ingress) which vela-app depends on are the built-in components and traits of KubeVela. You can also use -d or --definitions to specify your local definition files.

-d or --definitions permits users to provide capability definitions used in the application from local files. dry-run cmd will prioritize the provided capabilities than the living ones in the cluster.