Suspend and Resume

This section introduces how to suspend and resume the workflow in KubeVela.

Suspend the Workflow

In KubeVela, you can choose to use the vela command to manually suspend the execution of the workflow, or use a built-in special step type suspend to automatically suspend the workflow.

Suspend Manually

If you have an application in runningWorkflow state, you want to stop the execution of the workflow, you can use vela workflow suspend to stop the workflow and use vela workflow resume to continue it.

• Suspend the application

vela workflow suspend my-app

tip

Nothing will happen if you suspend an application that has already finished running workflow, which is in running status.

Use Suspend Step

Apply the following example:

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: suspend-demo
  namespace: default
spec:
  components:
  - name: comp1
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
  - name: comp2
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
  workflow:
    steps:
    - name: apply1
      type: apply-component
      properties:
        component: comp1
    - name: suspend
      type: suspend
    - name: apply2
      type: apply-component
      properties:
        component: comp2

Use vela status to check the status of the Application:

vela status suspend-demo

expected output

About:

  Name:         suspend-demo
  Namespace:    default
  Created at:   2022-06-27 17:36:58 +0800 CST
  Status:       workflowSuspending

Workflow:

  mode: StepByStep
  finished: false
  Suspend: true
  Terminated: false
  Steps
  - id:yj9h29uv6v
    name:apply1
    type:apply-component
    phase:succeeded
  - id:xvmda4he5e
    name:suspend
    type:suspend
    phase:running

Services:

  - Name: comp1
    Cluster: local  Namespace: default
    Type: webservice
    Healthy Ready:1/1
    No trait applied

As you can see, when the first step is completed, the suspend step will be executed and this step will suspend the workflow.

Resume the Workflow

Resume Manually

Once the workflow is suspended, you can use the vela workflow resume command to manually resume the workflow.

Take the above suspended application as an example:

vela workflow resume suspend-demo

After successfully continuing the workflow, view the status of the app:

vela status suspend-demo

expected output

About:

  Name:         suspend-demo
  Namespace:    default
  Created at:   2022-06-27 17:36:58 +0800 CST
  Status:       running

Workflow:

  mode: StepByStep
  finished: true
  Suspend: false
  Terminated: false
  Steps
  - id:yj9h29uv6v
    name:apply1
    type:apply-component
    phase:succeeded
    message:
  - id:xvmda4he5e
    name:suspend
    type:suspend
    phase:succeeded
    message:
  - id:66jonaxjef
    name:apply2
    type:apply-component
    phase:succeeded
    message:

Services:

  - Name: comp2
    Cluster: local  Namespace: default
    Type: webservice
    Healthy Ready:1/1
    No trait applied

  - Name: comp1
    Cluster: local  Namespace: default
    Type: webservice
    Healthy Ready:1/1
    No trait applied

As you can see, the workflow has continued to execute.

Terminate Manually

If you want to terminate a workflow while it is suspended, you can use the vela workflow terminate command to terminate the workflow.

• Terminate the application workflow

vela workflow terminate my-app

tip

Different from suspend, the terminated application workflow can't be resumed, you can only restart the workflow. This means restart the workflow will execute the workflow steps from scratch while resume workflow only continue the unfinished steps.

• Restart the application workflow

vela workflow restart my-app

caution

Once application is terminated, KubeVela controller won't reconcile the application resources. It can also be used in some cases when you want to manually operate the underlying resources, please caution the configuration drift.

Once application come into running status, it can't be terminated or restarted.

Resume the Workflow Automatically

If you want the workflow to be continued automatically after a period of time has passed. Then, you can add a duration parameter to the suspend step. When the duration time elapses, the workflow will automatically continue execution.

Apply the following example:

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: auto-resume
  namespace: default
spec:
  components:
  - name: comp1
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
  - name: comp2
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
  workflow:
    steps:
    - name: apply1
      type: apply-component
      properties:
        component: comp1
    - name: suspend
      type: suspend
      properties:
        duration: 5s
    - name: apply2
      type: apply-component
      properties:
        component: comp2

Use vela status to check the status of the Application:

vela status auto-resume

expected output

About:

  Name:         auto-resume
  Namespace:    default
  Created at:   2022-06-27 17:57:35 +0800 CST
  Status:       running

Workflow:

  mode: StepByStep
  finished: true
  Suspend: false
  Terminated: false
  Steps
  - id:q5jhm6mgwv
    name:apply1
    type:apply-component
    phase:succeeded
    message:
  - id:3xgfcp3cuj
    name:suspend
    type:suspend
    phase:succeeded
    message:
  - id:zjux8ud876
    name:apply2
    type:apply-component
    phase:succeeded
    message:

Services:

  - Name: comp2
    Cluster: local  Namespace: default
    Type: webservice
    Healthy Ready:1/1
    No trait applied

  - Name: comp1
    Cluster: local  Namespace: default
    Type: webservice
    Healthy Ready:1/1
    No trait applied

As you can see, the suspend step is automatically executed successfully after five seconds, and the workflow is executed successfully.