Launching jobs

Hue has a lot of long-running processes deployed as microservices, but it also has a lot of tasks that run, accomplish some goal, and exit. Kubernetes supports this functionality through the job resource. A Kubernetes job manages one or more pods and ensures that they run until success. If one of the pods managed by the job fails or is deleted, then the job will run a new pod until it succeeds.

Here is a job that runs a Python process to compute the factorial of 5 (hint: it's 120):

apiVersion: batch/v1
kind: Job
metadata:
  name: factorial5
spec:
  template:
    metadata:
      name: factorial5
    spec:
      containers:
      - name: factorial5
        image: python:3.6
        command: ["python", 
                  "-c", 
                  "import math; print(math.factorial(5))"]
      restartPolicy: Never      

Note that the restartPolicy must be either Never or OnFailure. The default Always value is invalid because a job shouldn't restart after successful completion.

Let...