workflow-running-forever.yaml

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: test-
  namespace: argo
spec:
  entrypoint: reproduce

  arguments:
    parameters:
      - name: items
        value: |
          [ "1", "2", "3", "4" ]

# Steps

  templates:

    - name: reproduce
      steps:
        - - name: step1
            template: sub-steps
            arguments:
              parameters:
                - name: cluster
                  value: "{{item}}"
            withParam: "{{workflow.parameters.items}}"
        - - name: step2
            template: sub-steps
            arguments:
              parameters:
                - name: cluster
                  value: "{{item}}"
            withParam: "{{workflow.parameters.items}}"

    - name: sub-steps
      steps:
        - - name: foo
            template: exec
        - - name: bar
            template: exec
        - - name: baz
            template: exec

# Containers

    - name: exec
      container:
        image: alpine
        command: [sh, -c]
        args:
          - |
            echo foo (bar)

This is for argo 2.2.1, I deployed argo constrained to a namespace using https://github.com/argoproj/argo/tree/master/manifests/namespace-install