Kubernetes Resources

In many cases, you will want to manage Kubernetes resources from Argo workflows. The resource template allows you to create, delete or updated any type of Kubernetes resource.

# in a workflow. The resource template type accepts any k8s manifest
# (including CRDs) and can perform any `kubectl` action against it (e.g. create,
# apply, delete, patch).
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: k8s-jobs-
spec:
  entrypoint: pi-tmpl
  templates:
  - name: pi-tmpl
    resource:                   # indicates that this is a resource template
      action: create            # can be any kubectl action (e.g. create, delete, apply, patch)
      # The successCondition and failureCondition are optional expressions.
      # If failureCondition is true, the step is considered failed.
      # If successCondition is true, the step is considered successful.
      # They use kubernetes label selection syntax and can be applied against any field
      # of the resource (not just labels). Multiple AND conditions can be represented by comma
      # delimited expressions.
      # For more details: https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/
      successCondition: status.succeeded > 0
      failureCondition: status.failed > 3
      manifest: |               #put your kubernetes spec here
        apiVersion: batch/v1
        kind: Job
        metadata:
          generateName: pi-job-
        spec:
          template:
            metadata:
              name: pi
            spec:
              containers:
              - name: pi
                image: perl
                command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]
              restartPolicy: Never
          backoffLimit: 4

Note: Currently only a single resource can be managed by a resource template so either a generateName or name must be provided in the resource's meta-data.

Resources created in this way are independent of the workflow. If you want the resource to be deleted when the workflow is deleted then you can use Kubernetes garbage collection with the workflow resource as an owner reference (example).

You can also collect data about the resource in output parameters (see more at k8s-jobs.yaml)

Note: When patching, the resource will accept another attribute, mergeStrategy, which can either be strategic, merge, or json. If this attribute is not supplied, it will default to strategic. Keep in mind that Custom Resources cannot be patched with strategic, so a different strategy must be chosen. For example, suppose you have the CronTab CRD defined, and the following instance of a CronTab:

apiVersion: "stable.example.com/v1"
kind: CronTab
spec:
  cronSpec: "* * * * */5"
  image: my-awesome-cron-image

This CronTab can be modified using the following Argo Workflow:

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: k8s-patch-
spec:
  entrypoint: cront-tmpl
  templates:
  - name: cront-tmpl
    resource:
      action: patch
      mergeStrategy: merge                 # Must be one of [strategic merge json]
      manifest: |
        apiVersion: "stable.example.com/v1"
        kind: CronTab
        spec:
          cronSpec: "* * * * */10"
          image: my-awesome-cron-image

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