An E-MapReduce workflow can be represented as a directed acyclic graph (DAG). You can pause, stop, and resume workflows. You can also view the running status of workflows in the web UI.

Create a workflow

  1. Log on to the Alibaba Cloud E-MapReduce console.
  2. Click the Data Platform tab to go to the Projects page.
  3. Click Workflows in the Actions column for a project. Click the Workflows tab and go to the Workflows page.
  4. Right-click the target folder and click Create Workflow.
  5. In the Create Workflow dialog box, enter a name and description for the workflow. Select a cluster from the Target Cluster drop-down list.

    You can select an existing cluster (Subscription or Pay-As-You-Go) that is associated with the project to run the workflow, or you can use a cluster template to create a temporary cluster for running the workflow.

  6. Click OK.

Edit a workflow

You can drag and drop multiple types of job nodes on the Workflows canvas and connect the nodes to schedule jobs. After the jobs are scheduled, drag the END controller node, drop it on the canvas, and connect it to a job node to complete the workflow design.

Configure a workflow

In the upper-right corner of the Workflows canvas, click Configure to schedule a workflow.

  • Target Cluster
    Select a cluster for running the jobs in the workflow. From the Target Cluster drop-down list, select Select Existing Cluster or Create Cluster from Template.
    • Select Existing Cluster: When the workflow is executed, the jobs run on the existing cluster that you have selected.
    • Create Cluster from Template: When the workflow is executed, the jobs run on the temporary cluster created by using the Cluster template that you have selected. The cluster is released when the workflow finishes.
  • Scheduling: When scheduling is enabled, time-based scheduling is applied by default. You can also configure rules for dependency-based scheduling.
    • Time-based Scheduling: Sets a start time, an end time, and a cycle for scheduling the workflow. During this period, the workflow is executed according to the cycle you have set.
    • Dependency-based Scheduling: Selects a project and selects a dependent workflow. The workflow is scheduled only when the dependent workflow finishes. You can select a maximum of one dependent workflow.
  • Configure alerts
    Alerts can be sent by SMS, email, and DingTalk group. You can configure the following alerting rules:
    • Execution Failed: alerts that are sent when a workflow fails.
    • Actions on Failures: alerts that are sent when job nodes of a workflow fail.
    • Executed: notifications that are sent when a workflow succeeds.
    • Action on Startup Timeout: When a job node fails to start 30 minutes after it is assigned to a cluster, an alert is sent and the job is canceled.

Run a workflow

After the design and configuration are complete, click Run to run the workflow.

View and operate a workflow instance

After you run the workflow, click the Records tab page to view the running status of the workflow instance. Click Details for the workflow instance to view the running status of the workflow instance. You can also pause, resume, stop, or rerun the workflow instance.
  • Pause Workflow: The job node that is running continues. The subsequent job nodes do not start. You can click Resume Workflow to start the subsequent job nodes again.
  • Stop Workflow: All running job nodes stop running.
  • Rerun Workflow: The workflow runs from the START node.