Create a workflow - User Guide for Genomics Service| Alibaba Cloud Documentation Center

Based on Argo Workflows, workflows that are developed by Alibaba Cloud are used to implement containerized job 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 the command-line interface (CLI).

Prerequisites

Background information

Based on Argo Workflows, workflows that are developed by Alibaba Cloud are used to implement containerized job orchestration in Kubernetes. Each step in a workflow is a container.

Each workflow is implemented as a Kubernetes CustomResourceDefinition(CRD). 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 list of workflow features, such as parameter substitution, storage, loops, and recursion.

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

Create workflows in the ACK console

Log on to the ACK console.
In the left-side navigation pane, click Clusters.
On the Clusters page, click the name of a cluster or click Details in the Actions column. The details page of the cluster appears.
In the left-side navigation pane, click Releases.
On the Releases page, click the Workflows tab. On the upper-right corner of the Workflows tab, click Create.
In the Create from Template dialog box, set the parameters, configure the template, and then click Create.
- Cluster: Select a cluster. 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 describe the resource that you want to define.
The following example is a custom template that is used to create a Hello World workflow:
```
apiVersion: argoproj.io/v1alpha1
kind: Workflow                  # new type of k8s spec
metadata:
  generateName: hello-world-    # name of the workflow spec
spec:
  entrypoint: whalesay          # invoke the whalesay template
  templates:
  - name: whalesay              # name of the template
    container:
      image: docker/whalesay
      command: [cowsay]
      args: ["hello world"]
      resources:                # limit the resources
        limits:
          memory: 32Mi
          cpu: 100m
```
After the workflow is created, you can view the created workflow on the Workflows tab.
You can click Details in the Actions column to view information about the workflow and container groups.

Create parameters workflows by using the CLI

Create a YAML file named arguments-parameters.yaml and paste the following content into the file:

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: hello-world-parameters-
spec:
  # invoke the whalesay template with
  # "hello world" as the argument
  # to the message parameter
  entrypoint: whalesay
  arguments:
    parameters:
    - name: message
      value: hello world

  templates:
  - name: whalesay
    inputs:
      parameters:
      - name: message       # parameter declaration
    container:
      # run cowsay with that message input parameter as args
      image: docker/whalesay
      command: [cowsay]
      args: ["{{inputs.parameters.message}}"]

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 workflows.

Ags CLI is a command-line interface 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.