Dry Run

    When you do the following things, you’d better use .

    • Create or update an application.
    • Create or update the definition, and dry run some example applications.

    There is a simple application:

    Copy it and write a file app.yaml, execute the following command, and then the resources will be printed.

    1. vela dry-run app.yaml

    expected output

    1. ---
    2. # Application(webservice-app) -- Component(frontend) 
    3. ---
    5. apiVersion: apps/v1
    6. kind: Deployment
    7. metadata:
    8.   annotations: {}
    9.   labels:
    10.     app.oam.dev/appRevision: ""
    11.     app.oam.dev/component: frontend
    12.     app.oam.dev/name: webservice-app
    13.     app.oam.dev/namespace: default
    14.     app.oam.dev/resourceType: WORKLOAD
    15.     workload.oam.dev/type: webservice
    16.   name: frontend
    17.   namespace: default
    18. spec:
    19.   replicas: 1
    20.   selector:
    21.     matchLabels:
    22.       app.oam.dev/component: frontend
    23.   template:
    24.     metadata:
    25.       labels:
    26.         app.oam.dev/component: frontend
    27.         app.oam.dev/name: webservice-app
    28.     spec:
    29.       containers:
    30.       - command:
    31.         - node
    32.         - server.js
    33.         image: oamdev/testapp:v1
    34.         name: frontend
    35.         ports:
    36.         - containerPort: 8080
    37.           name: port-8080
    38.           protocol: TCP
    40. ---
    41. ## From the auxiliary workload 
    42. apiVersion: v1
    43. kind: Service
    44. metadata:
    45.   annotations: {}
    46.   labels:
    47.     app.oam.dev/appRevision: ""
    48.     app.oam.dev/component: frontend
    49.     app.oam.dev/name: webservice-app
    50.     app.oam.dev/namespace: default
    51.     app.oam.dev/resourceType: TRAIT
    52.     trait.oam.dev/resource: webserviceExpose
    53.     trait.oam.dev/type: AuxiliaryWorkload
    54.   name: frontend
    55.   namespace: default
    56. spec:
    57.   ports:
    58.   - name: port-8080
    59.     port: 8080
    60.     targetPort: 8080
    61.   selector:
    62.     app.oam.dev/component: frontend
    63.   type: ClusterIP
    65. ---

    If we set the expose field of the port as false, the output resources do not include the Service. If we set the replicas field as “1”, the output will be an error message:

    1. Error: validate application: ./app.yaml by dry-run: admission webhook "validating.core.oam.dev.v1beta1.applications" denied the request: field "schematic": Invalid value error encountered, cannot evaluate trait "scaler": invalid template of trait scaler after merge with parameter and context: parameter.replicas: conflicting values (*1 | int) and "1" (mismatched types int and string) (and 1 more errors).

    This means the replicas field is int type but we provide a string value, this application configuration is not valid.

    tip

    Override/topology Policies and deploy workflow are supported in v1.7.0+ now. While there’re still some limitation that dry-run with policy and workflow will only take override, topology policies and deploy workflow step into considerations. Other workflow steps will be ignored.

    Let’s take the following application as example, the application explicitly specify override, topology policies and deploy workflow step.

    1. apiVersion: core.oam.dev/v1beta1
    2. kind: Application
    3. metadata:
    4.   name: first-vela-app
    5. spec:
    6.   components:
    7.     - name: express-server
    8.       type: webservice
    9.       properties:
    10.         image: oamdev/hello-world
    11.         ports:
    12.          - port: 8000
    13.            expose: true
    14.       traits:
    15.         - type: scaler
    16.           properties:
    17.             replicas: 1
    18.   policies:
    19.     - name: target-default
    20.       type: topology
    21.       properties:
    22.         clusters: ["local"]
    23.         namespace: "default"
    24.     - name: target-prod
    25.       type: topology
    26.       properties:
    27.         clusters: ["local"]
    28.         namespace: "prod"
    29.     - name: deploy-ha
    30.       type: override
    31.       properties:
    32.         components:
    33.           - type: webservice
    34.             traits:
    35.               - type: scaler
    36.                 properties:
    37.                   replicas: 5
    38.   workflow:
    39.     steps:
    40.       - name: deploy2default
    41.         type: deploy
    42.         properties:
    43.           policies: ["target-default"]
    44.       - name: manual-approval
    45.         type: suspend
    46.       - name: deploy2prod
    47.         type: deploy
    48.         properties:
    49.           policies: ["target-prod", "deploy-ha"]

    Dry run will produce rendered results for both deploy2default and deploy2prod deploy steps as below:

    expected output

    1. ---
    2. # Application(first-vela-app with topology target-default) -- Component(express-server) 
    3. ---
    5. apiVersion: apps/v1
    6. kind: Deployment
    7. metadata:
    8.   annotations: {}
    9.   labels:
    10.     app.oam.dev/appRevision: ""
    11.     app.oam.dev/component: express-server
    12.     app.oam.dev/name: first-vela-app
    13.     app.oam.dev/namespace: default
    14.     app.oam.dev/resourceType: WORKLOAD
    15.     workload.oam.dev/type: webservice
    16.   name: express-server
    17.   namespace: default
    18. spec:
    19.   replicas: 1
    20.   selector:
    21.     matchLabels:
    22.       app.oam.dev/component: express-server
    23.   template:
    25.       labels:
    26.         app.oam.dev/component: express-server
    27.         app.oam.dev/name: first-vela-app
    28.       containers:
    29.       - image: oamdev/hello-world
    30.         name: express-server
    31.         ports:
    32.         - containerPort: 8000
    33.           name: port-8000
    34.           protocol: TCP
    36. ---
    37. ## From the auxiliary workload 
    38. apiVersion: v1
    39. kind: Service
    40. metadata:
    41.   annotations: {}
    42.   labels:
    43.     app.oam.dev/appRevision: ""
    44.     app.oam.dev/component: express-server
    45.     app.oam.dev/name: first-vela-app
    46.     app.oam.dev/namespace: default
    47.     app.oam.dev/resourceType: TRAIT
    48.     trait.oam.dev/resource: webserviceExpose
    49.     trait.oam.dev/type: AuxiliaryWorkload
    50.   name: express-server
    51.   namespace: default
    52. spec:
    53.   ports:
    54.   - name: port-8000
    55.     port: 8000
    56.     targetPort: 8000
    57.   selector:
    58.     app.oam.dev/component: express-server
    59.   type: ClusterIP
    61. ---
    63. ---
    64. # Application(first-vela-app with topology target-prod) -- Component(express-server) 
    65. ---
    67. apiVersion: apps/v1
    68. kind: Deployment
    69. metadata:
    70.   annotations: {}
    71.   labels:
    72.     app.oam.dev/appRevision: ""
    73.     app.oam.dev/component: express-server
    74.     app.oam.dev/name: first-vela-app
    75.     app.oam.dev/namespace: default
    76.     app.oam.dev/resourceType: WORKLOAD
    77.     workload.oam.dev/type: webservice
    78.   name: express-server
    79.   namespace: default
    80. spec:
    81.   replicas: 5
    82.   selector:
    83.     matchLabels:
    84.       app.oam.dev/component: express-server
    85.   template:
    86.     metadata:
    87.       labels:
    88.         app.oam.dev/component: express-server
    89.         app.oam.dev/name: first-vela-app
    90.     spec:
    91.       containers:
    92.       - image: oamdev/hello-world
    93.         name: express-server
    94.         ports:
    95.         - containerPort: 8000
    96.           name: port-8000
    97.           protocol: TCP
    99. ---
    100. ## From the auxiliary workload 
    101. apiVersion: v1
    102. kind: Service
    103. metadata:
    104.   annotations: {}
    105.   labels:
    106.     app.oam.dev/appRevision: ""
    107.     app.oam.dev/component: express-server
    108.     app.oam.dev/name: first-vela-app
    109.     app.oam.dev/namespace: default
    110.     app.oam.dev/resourceType: TRAIT
    111.     trait.oam.dev/resource: webserviceExpose
    112.     trait.oam.dev/type: AuxiliaryWorkload
    113.   name: express-server
    114.   namespace: default
    115. spec:
    116.   ports:
    117.   - name: port-8000
    118.     port: 8000
    119.     targetPort: 8000
    120.   selector:
    121.     app.oam.dev/component: express-server
    122.   type: ClusterIP
    124. ---

    It can be a bit redundant for you as you may just need to dry run for one environment at a time. The, you can use the external workflow feature like below.

    Firstly, define policy and workflow as below in individual files:

    • The target-prod.yaml and ha.yaml corresponding to the production environment.

      1. # ha.yaml
      2. apiVersion: core.oam.dev/v1alpha1
      3. kind: Policy
      4. metadata:
      5.   name: ha
      6. type: override
      7. properties:
      8.   components:
      9.   - type: webservice
      10.     traits:
      11.     - type: scaler
      12.       properties:
      13.         replicas: 5

    • The prod-workflow.yaml can glue them together.

      1. # prod-workflow.yaml
      2. apiVersion: core.oam.dev/v1alpha1
      3. kind: Workflow
      4. metadata:
      5.   name: deploy-prod
      6. steps:
      7.   - type: deploy
      8.     name: deploy-prod
      9.     properties:
      10.       policies: ["ha", "target-prod"]

    • Then the application can reference the workflow as below.

      1. apiVersion: core.oam.dev/v1beta1
      2. kind: Application
      3. metadata:
      4.   name: first-vela-app
      5. spec:
      6.   components:
      7.     - name: express-server
      8.       type: webservice
      9.       properties:
      10.         image: oamdev/hello-world
      11.         ports:
      12.         - port: 8000
      13.           expose: true
      14.       traits:
      15.         - type: scaler
      16.           properties:
      17.             replicas: 1
      18.   workflow:
      19.     ref: deploy-prod

    The dry run command can be:

    1. vela dry-run -f app.yaml -f target-prod.yaml -f ha.yaml -f prod-workflow.yaml

    Then, the dry-run results will only contain resources in the production environment.

    expected output

    1. ---
    4. apiVersion: apps/v1
    5. kind: Deployment
    6. metadata:
    7.   annotations: {}
    8.   labels:
    9.     app.oam.dev/appRevision: ""
    10.     app.oam.dev/component: express-server
    11.     app.oam.dev/name: first-vela-app
    12.     app.oam.dev/namespace: default
    13.     app.oam.dev/resourceType: WORKLOAD
    14.     workload.oam.dev/type: webservice
    15.   name: express-server
    16.   namespace: default
    17. spec:
    18.   replicas: 5
    19.   selector:
    20.     matchLabels:
    21.       app.oam.dev/component: express-server
    22.   template:
    23.     metadata:
    24.       labels:
    25.         app.oam.dev/component: express-server
    26.         app.oam.dev/name: first-vela-app
    27.     spec:
    28.       containers:
    29.       - image: oamdev/hello-world
    30.         name: express-server
    31.         ports:
    32.         - containerPort: 8000
    33.           name: port-8000
    34.           protocol: TCP
    36. ---
    37. ## From the auxiliary workload 
    38. apiVersion: v1
    39. kind: Service
    40. metadata:
    41.   annotations: {}
    42.   labels:
    43.     app.oam.dev/appRevision: ""
    44.     app.oam.dev/component: express-server
    45.     app.oam.dev/name: first-vela-app
    46.     app.oam.dev/namespace: default
    47.     app.oam.dev/resourceType: TRAIT
    48.     trait.oam.dev/resource: webserviceExpose
    49.     trait.oam.dev/type: AuxiliaryWorkload
    50.   name: express-server
    51.   namespace: default
    52. spec:
    53.   ports:
    54.   - name: port-8000
    55.     port: 8000
    56.     targetPort: 8000
    57.   selector:
    58.     app.oam.dev/component: express-server
    59.   type: ClusterIP
    61. ---

    Moreover, you can use --merge flag to merge external policies and workflow when application file is not reference to them.

    For example, you can define the application as below, the only difference is there’s no workflow field.

    the workflow and policy can be defined the same way

    1. # workflow.yaml
    2. apiVersion: core.oam.dev/v1alpha1
    3. kind: Workflow
    4. metadata:
    5.   name: deploy-demo
    6. steps:
    7.   - type: deploy
    8.     name: deploy-prod
    9.     properties:
    10.       policies: ["target-prod"]
    1. # target-prod.yaml
    2. apiVersion: core.oam.dev/v1alpha1
    3. kind: Policy
    4. metadata:
    5.   name: target-prod
    6. type: topology
    7. properties:
    8.   clusters: ["local"]
    9.   namespace: "prod"
    1. vela dry-run -f app.yaml -f target-prod.yaml -f workflow.yaml

    result with warning messages

    1. WARNING: workflow deploy-demo not referenced by application
    3. WARNING: policy target-prod not referenced by application
    5. ---
    6. # Application(default) -- Component(express-server) 
    7. ---
    9. apiVersion: apps/v1
    10. kind: Deployment
    11. metadata:
    12.   annotations: {}
    13.   labels:
    14.     app.oam.dev/appRevision: ""
    15.     app.oam.dev/component: express-server
    16.     app.oam.dev/name: first-vela-app
    17.     app.oam.dev/namespace: default
    18.     app.oam.dev/resourceType: WORKLOAD
    19.     workload.oam.dev/type: webservice
    20.   name: express-server
    21.   namespace: default
    22. spec:
    23.   replicas: 1
    24.   selector:
    25.     matchLabels:
    26.       app.oam.dev/component: express-server
    27.   template:
    28.     metadata:
    29.       labels:
    30.         app.oam.dev/component: express-server
    31.         app.oam.dev/name: first-vela-app
    32.     spec:
    33.       containers:
    34.       - image: oamdev/hello-world
    35.         name: express-server
    36.         ports:
    37.         - containerPort: 8000
    38.           name: port-8000
    39.           protocol: TCP
    41. ---
    42. ## From the auxiliary workload 
    43. apiVersion: v1
    44. kind: Service
    45. metadata:
    46.   annotations: {}
    47.   labels:
    48.     app.oam.dev/appRevision: ""
    49.     app.oam.dev/component: express-server
    50.     app.oam.dev/name: first-vela-app
    51.     app.oam.dev/namespace: default
    52.     app.oam.dev/resourceType: TRAIT
    53.     trait.oam.dev/resource: webserviceExpose
    54.     trait.oam.dev/type: AuxiliaryWorkload
    55.   name: express-server
    56.   namespace: default
    57. spec:
    58.   ports:
    59.   - name: port-8000
    60.     port: 8000
    61.     targetPort: 8000
    62.   selector:
    63.     app.oam.dev/component: express-server
    64.   type: ClusterIP
    66. ---

    In this case, the policy and workflow do not take effect. Because those are not referenced by the application and being viewed as standalone files and ignored.

    So to make those external files work, please provide “—merge” flag as below:

      Then the application will be glued with external policies and workflows even no reference exists.

      expected ouput

      You can refer to the Dry run command for more command line use cases.

      dry-run

      Clicking the button to open the workflow selector dialog. You could select a workflow(every workflow corresponding to an environment) and click the DryRun button to execute a dry run. If passed, the result is like this

      The result report is different from the CLI, there is a complete application configuration that is generated from the application metadata, you could check it. Different environments may have different application configurations.