Workflows developed by Alibaba Cloud are based on Argo Workflows and are used to implement container orchestration in Kubernetes. Each step in a workflow is a container. This topic describes how to create a workflow in the Container Service for Kubernetes (ACK) console or by using a CLI.

Prerequisites

Background information

Workflows developed by Alibaba Cloud are based on Argo Workflows and are used to implement container orchestration in Kubernetes. Each step in a workflow is a container.

Workflows are implemented by using Kubernetes CustomResourceDefinitions(CRDs). Therefore, you can use kubectl to manage workflows and integrate them with other Kubernetes services, such as volumes, Secrets, and role-based access control (RBAC). At the backend, the workflow controller provides a complete set of workflow features, such as parameter substitution, storage, loops, and recursion.

You can create workflows in the ACK console or by using a CLI.

Create a workflow in the ACK console

  1. Log on to the ACK console.
  2. In the left-side navigation pane of the ACK console, click Clusters.
  3. On the Clusters page, find the cluster that you want to manage and click the name of the cluster or click Details in the Actions column. The details page of the cluster appears.
  4. In the left-side navigation pane of the details page, choose Applications > Workflows.
  5. On the Workflows page, click Create in the upper-right corner of the page.
  6. In the Create from Template dialog box, configure the workflow and click Create.
    • Cluster: Select the cluster where you want to deploy the workflow. The workflow will be deployed in the selected cluster.
    • Namespace: Select the namespace to which the workflow belongs. By default, the default namespace is selected.
    • Sample Template: ACK provides YAML templates of various resource types to simplify the deployment of workflows. You can also create a custom template based on YAML syntax to customize resource definitions.
    The following code provides an example on how to create a Hello World workflow: 
    apiVersion: argoproj.io/v1alpha1
kind: Workflow                  # The type of Kubernetes object. 
metadata:
  generateName: hello-world-    # The name of the workflow. 
spec:
  entrypoint: whalesay          # Invoke the template of a whalesay image. 
  templates:
  - name: whalesay              # The name of the template.
    container:
      image: docker/whalesay
      command: [cowsay]
      args: ["hello world"]
      resources:                # The resource limits. 
        limits: 
          memory: 32Mi
          cpu: 100m
  7. After the workflow is created, you can view the created workflow on the Workflows page.
    Successful creation

    You can click Details in the Actions column to view information about the workflow and pods.

Create a parameters workflow by using a CLI

  1. Create an arguments-parameters.yaml file based on the following code: 
    apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: hello-world-parameters-
spec:
  # Specify "hello world" as the value of the parameter to invoke the template of a whalesay image. 
  entrypoint: whalesay
  arguments:
    parameters:
    - name: message
      value: hello world

  templates:
  - name: whalesay
    inputs:
      parameters:
      - name: message       # The description of the parameter. 
    container:
      # Use the input parameter args to run cowsay. 
      image: docker/whalesay 
      command: [cowsay]
      args: ["{{inputs.parameters.message}}"]
  2. Run the following command to deploy the parameters workflow: 
    ags submit arguments-parameters.yaml -p message="goodbye world"

You can also use workflow templates provided in Sample workflow templates to create other types of workflow.

Ags CLI is a command-line tool developed by Alibaba Cloud. It is compatible with open source Argo. Ags CLI provides an easy way to submit, check, modify, and delete workflows. For more information, see Introduction to AGS CLI.