Skip to main content
Explore the Steps template invoker type in Argo Workflows. Steps templates let you compose multi-step workflows that run tasks both sequentially and in parallel. This example workflow, named “Cosmic Move”, shows how a Steps template orchestrates reusable templates (here, cow-says) into a sequence of step groups with parallel execution inside groups. 
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: cosmic-moo-
spec:
  entrypoint: triple-moo
  templates:
  - name: triple-moo
    steps:
    - - name: first-moo
        template: cow-says
        arguments:
          parameters:
          - name: message
            value: "Cosmic Ranch!"
    - - name: parallel-moo-a
        template: cow-says
        arguments:
          parameters:
          - name: message
            value: "Galaxy Moo!"
      - name: parallel-moo-b
        template: cow-says
        arguments:
          parameters:
          - name: message
            value: "Milky Whey!"
  - name: cow-says
    inputs:
      parameters:
      - name: message
    container:
      image: rancher/cowsay
      command: ["cowsay"]
      args: ["{{inputs.parameters.message}}"]
How this workflow is wired:
  • The workflow entrypoint is triple-moo.
  • triple-moo uses a steps block to orchestrate calls to the reusable cow-says template.
  • cow-says is a simple container task that runs cowsay with the supplied message parameter.
Understanding the steps structure
  • steps is a list of step-groups (a list of lists).
    • Each top-level list item (each top-level -) is a step-group that executes in sequence.
    • Within a step-group, each inner - is an individual step that runs in parallel with the other inner steps in that group.
Think of steps as a sequence of step-groups: each top-level dash creates a group that runs one after another; steps inside the same group (inner dashes) run concurrently.
Execution semantics (summary):
  • Top-level elements (step-groups) run one after another (sequential).
  • Inner list elements inside a group run at the same time (parallel).
  • The workflow advances to the next group only after every step in the current group finishes.
Example: what happens in the “Cosmic Move” workflow
  • First step-group:
    • first-moo runs by itself. The workflow waits until it completes.
  • Second step-group:
    • parallel-moo-a and parallel-moo-b run concurrently. The workflow proceeds only after both finish.
When you inspect a running workflow with argo, the execution tree shows the sequence and parallel steps. Example output: 
$ argo -n argo get cosmic-moo-k2kxq

STEP                    TEMPLATE       PODNAME
✓ cosmic-moo-k2kxq      triple-moo
├─✓ first-moo            cow-says       cosmic-moo-k2kxq-cow-says-2575730875
├─✓ parallel-moo-a       cow-says       cosmic-moo-k2kxq-cow-says-1190566453
└─✓ parallel-moo-b       cow-says       cosmic-moo-k2kxq-cow-says-1140233596
Quick reference table
ConceptBehaviorExample
Step-group (top-level item)Runs sequentially relative to other groupsFirst group contains first-moo
Steps in a group (inner items)Run in parallel with each otherparallel-moo-a and parallel-moo-b
Entry pointTemplate name used to start the workflowentrypoint: triple-moo
Reusable templateCalled by steps with parameterscow-says accepts message parameter
Best practices
  • Use Steps templates when you need explicit ordering and occasional parallelism between tasks.
  • Keep reusable work in separate templates and pass parameters for customization.
  • Use clear step names to make the execution tree easy to read when inspecting runs with argo get.
Links and references

Watch Video