Docker & Kubernetes · Module 09

Kubernetes Workloads

Pick the right workload: ReplicaSets keep a pod count, Deployments update and roll back, DaemonSets run on every node, StatefulSets keep identity, Jobs/CronJobs run tasks.

Practice interactively →

What you will learn

• Explain pod templates, selectors and how a ReplicaSet keeps the pod count
• Create, update, scale and roll back Deployments
• Use DaemonSets with nodeSelector for per-node services
• Use StatefulSets with a headless Service and volumeClaimTemplates
• Run one-off and scheduled tasks with Jobs and CronJobs

Lessons

1. Pod templates, ReplicationControllers and ReplicaSets

   A ReplicaSet keeps the right number of pods matching its selector, creating them from a pod template; it is usually used through a Deployment.

2. Deployments — rolling updates, rollbacks, scaling

   A Deployment manages ReplicaSets to update pods gradually, keep a revision history and roll back at any time.

3. DaemonSets

   A DaemonSet runs exactly one pod on every eligible node; ideal for log, monitoring and networking agents.

4. StatefulSets and headless Services

   A StatefulSet gives each pod a stable identity — ordered name, own DNS, own PVC — for stateful applications.

5. Jobs, CronJobs and Operators

   A Job runs pods to completion; a CronJob creates Jobs on a cron schedule (UTC by default); an Operator is a custom controller for complex apps.