my-docs/kubernetes/workloads/job.md

1. Simple Job

This Job is configured to run a single container that prints "hello world" to the console.

apiVersion: batch/v1
kind: Job
metadata:
  name: myjob
  namespace: my-ns
spec:
  template:
    spec:
      containers:
      - name: myjob
        image: alpine
        command:
        - echo
        - "hello world"
      restartPolicy: Never

• apiVersion: batch/v1: Specifies the API version.
• kind: Job: Defines the object as a Job.
• metadata: Provides metadata for the Job.
  • name: The name of the Job (myjob).
  • namespace: The namespace where the Job will be created (my-ns).
• spec: Describes the desired state.
  • template: The pod template used by the Job.
    • spec: Describes the pod specification.
      • containers: Defines the containers within the pod.
        • name: The name of the container (myjob).
        • image: The container image (alpine).
        • command: The command to run in the container (echo "hello world").
      • restartPolicy: Specifies the restart policy for the pod (Never).

2. Job with Error and Retries

This Job attempts to list a non-existent directory (/chert) and will try to complete the task up to 6 times due to the error.

apiVersion: batch/v1
kind: Job
metadata:
  name: myjob
  namespace: my-ns
spec:
  backoffLimit: 6
  template:
    spec:
      containers:
      - name: myjob
        image: alpine
        command:
        - ls
        - "/chert"
      restartPolicy: Never

• apiVersion: batch/v1: Specifies the API version.
• kind: Job: Defines the object as a Job.
• metadata: Provides metadata for the Job.
  • name: The name of the Job (myjob).
  • namespace: The namespace where the Job will be created (my-ns).
• spec: Describes the desired state.
  • backoffLimit: The number of retries before the Job is considered failed (6).
  • template: The pod template used by the Job.
    • spec: Describes the pod specification.
      • containers: Defines the containers within the pod.
        • name: The name of the container (myjob).
        • image: The container image (alpine).
        • command: The command to run in the container (ls /chert).
      • restartPolicy: Specifies the restart policy for the pod (Never).

This guide provides a detailed explanation of Kubernetes Job YAML files. Jobs are designed to run a task to completion, and they can retry in case of failures. Each Job configuration includes specifications for containers, commands, and restart policies, with the option to set a retry limit for handling errors.