User guide

This document is meant to be a guide for new users of how to create and submit Jobs to Armada. Because Armada jobs are run as containers in Kubernetes, a basic understanding of Docker and Kubernetes is required; see, e.g., the following links:

For more information about the design of Armada (e.g., how jobs are prioritised), see:

The Armada workflow is:

  1. Create a job specification, which is a Kubernetes podspec with additional metadata fields specific to Armada.
  2. Submit the job specification to one of Armada’s job queues.

To create a job that sleeps for 60 seconds, start by creating a yaml file with the following contents:

queue: test
jobSetId: set1
  - priority: 0
      - terminationGracePeriodSeconds: 0
        restartPolicy: Never
          - name: sleep
            imagePullPolicy: IfNotPresent
            image: busybox:latest
              - sleep
              - 60s
                memory: 64Mi
                cpu: 150m
                memory: 64Mi
                cpu: 150m

In the above yaml snippet, podSpec is a Kubernetes podspec, which consists of one or more containers that contain the user code to be run. In addition, the job specification (jobspec) contains metadata fields specific to Armada:

Resource requests and limits must be equal. Armada does not yet support limit > request.

Now, the job can be submitted to Armada using the armadactl command-line utility (or alternatively via Armada’s gRPC or REST API). In particular, run

armadactl submit <jobspec.yaml>,

where <jobspec.yaml> is the path of the file containing the jobspec. Armada automatically handles creating and running the necessary containers.

Preemptive jobs

Armada supports submitting preemptive jobs, i.e. jobs which can preempt other lower priority jobs when there aren’t enough resources to run the preemptive job.

For scheduling preemptive jobs, Armada relies on the kube-scheduler component of Kubernetes for the actual preemption and scheduling the underlying pods.

More info on preemption in Kubernetes can be found in the official docs.

To use priority and preemption in Armada:

  1. Add one or more PriorityClasses.
  2. Create Armada jobs with priorityClassName in the job’s podSpec set to one of the existing PriorityClasses.


Job options

Here, we give a complete example of an Armada jobspec with all available parameters.

queue: example                            # 1.
jobSetId: test                            # 2.
  - priority: 1000                        # 3.
    namespace: example                    # 4.
    clientId: 12345                       # 5.
    labels:                               # 6.
      example-label: "value"
    annotations:                          # 7.
      example-annotation: "value"
    ingress:                              # 8.
      - type: NodePort
          - 5050
    podSpecs:                             # 9.
      - containers:
        name: app
        imagePullPolicy: IfNotPresent
        image: vad1mo/hello-world-rest:latest
          runAsUser: 1000
            memory: 1Gi
            cpu: 1
            memory: 1Gi
            cpu: 1
          - containerPort: 5050
            protocol: TCP
            name: http

Using this format, it is possible to submit a job set composed of several jobs. The meaning of each field is:

  1. The queue this job will be submitted to.
  2. Name of the job set this job belongs to.
  3. Relative priority of the job.
  4. The namespace that the pods part of this job will be created in (the default namespace if not specified).
  5. An optional ID that can be set to ensure that jobs are not duplicated, e.g., in case of certain network failures. Armada automatically discards any jobs submitted with a clientId equal to that of an existing job.
  6. List of labels that are added to all pods created as part of this job..
  7. List annotations that are added to all pods created as part of this job.
  8. List of ports that are exposed with the specified ingress type. The ingress only exposes ports for pods that also expose the corresponding port via the containerPort setting.
  9. List of podspecs that make up the job; see the Kubernetes documentation for an overview of the available parameters.