Kubernetes Jobs: Running Tasks in Kubernetes

Creating a Job

Initiate a job that runs a specific command in a container:

kubectl create job busybox --image=busybox -- /bin/sh -c "echo hello; sleep 30; echo world"

Managing Jobs
Check the status and details of all jobs in the current namespace:

kubectl get jobs

Viewing Job Logs
Retrieve logs from a specific pod created by a job:

kubectl logs <pod-name>

Deleting a Job
Remove a job and its associated pods:

kubectl delete job <job-name>

Understanding Job Properties
Jobs have several key properties to consider:

completions
: Number of pod completions expected.
backoffLimit: Maximum number of retries before considering a job as failed.

parallelism
: Number of pods to run in parallel.
activeDeadlineSeconds: Maximum time for the job to run.
restartPolicy: Pod restart policy, usually set to "OnFailure" or "Never".

Important Notes

In a job, the default value for the restart property is "Never."
A pod created by a job must have its restartPolicy set to "OnFailure" or "Never."

CronJobs: Scheduled Jobs

Managing CronJobs
List all CronJobs in the current namespace:

kubectl get cronjobs

Creating a CronJob
Establish a CronJob that runs on a specified schedule:

kubectl create cronjob busybox --image=busybox --schedule="*/1 * * * *" -- /bin/sh -c "date; echo Hello from Kubernetes cluster"

Specifying CronJob Properties
In a CronJob, there are three spec sections to note - one for the CronJob itself, one for the Job, and one for the Pod. Important properties include:

spec -> successfulJobHistoryLimit: Number of successful jobs to retain in history.
spec -> failedJobHistoryLimit: Number of failed jobs to retain in history.
Explore the capabilities of Kubernetes Jobs and CronJobs, enhancing your control over task execution and scheduling within your cluster.

Happy Kuberneting!