The Work Gym

Courses / Developer tools

Docker and Kubernetes

Build images, operate services and diagnose cluster workloads.

Start lesson 1 Practice interview Take the assessmentPractice the first unit of every course. No account needed.

60lessons

320checked exercises

12projects, cases and exams

Prepares you for Backend and DevOps interviews and CKAD objectives

Projects, case studies and mock exams

Project · IntermediateMedia preview stack

A media producer needs a repeatable preview environment with a web process and a cache.

6 steps · 45 min Case study · IntermediateScheduling API crash loop

A fictional appointment API repeatedly restarts even though its Pod is scheduled.

6 steps · 35 min Case study · IntermediateRetail image pull failure

A fictional retail preview never starts after a release reference changes.

6 steps · 35 min Case study · AdvancedTravel worker scheduling

A fictional travel worker remains Pending while its team waits for a scheduled export.

6 steps · 35 min Case study · AdvancedLogistics service outage

A logistics service exists, and its application Pods are running, but the stable address has no useful backend.

6 steps · 35 min Project · AdvancedPayments release workspace

A payments release needs a complete application boundary, not just one running Pod.

6 steps · 45 min Project · ExpertHealthcare batch platform

A healthcare scheduling team needs a batch workspace with persistent output and limited privileges.

6 steps · 45 min Mock exam · ExpertApplication developer mock one

Complete an original timed practical across application resources.

10 questions · 120 min Mock exam · ExpertApplication developer mock two

Complete an original timed practical across application resources.

10 questions · 120 min

Work in a local terminal that models Docker images, build layers, container processes and Kubernetes application resources. Start with versioned images and runtime configuration, then build a connected service stack, deploy configured workloads and trace traffic through Services and Ingress. Practice probes, capacity, storage, scheduled work and release recovery on original fictional systems. Projects preserve your work between steps. Four incident cases, role-based interview sets and two timed practical mocks test whether you can inspect evidence and repair the right boundary. The course covers application developer objectives with explicit limits around external controllers and cloud infrastructure.

Beginner

Image and process basics

Inspect versioned images and manage container processes.

4 lessons

1Images and versionsIdentify and prepare exact image versions before starting a process.4 exercises · 18 minFree

2Container creationStart named containers with explicit runtime settings.4 exercises · 18 minFree

3Process inspection and cleanupRead logs, run container commands and distinguish stop from removal.4 exercises · 18 minFree

Practice setImage and process basics practiceCombine the unit's skills on a fresh set of original operational requests.Free

Runtime configuration

Publish ports, pass environment values, and keep data outside the container layer.

4 lessons

5Port publishingMap a host listener to the application port inside a container.4 exercises · 18 minWith a plan

6Runtime environmentPass explicit configuration into a container without changing its image.4 exercises · 18 minWith a plan

7Volumes and bind mountsChoose storage by its lifecycle and map it to the correct container path.4 exercises · 18 minWith a plan

Practice setRuntime configuration practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Build and distribution

Build reusable image layers and distribute versioned releases.

4 lessons

9Dockerfile application imagesBuild an image with the expected files and startup metadata.4 exercises · 18 minWith a plan

10Build cache boundariesDistinguish reusable dependency layers from layers invalidated by a change.4 exercises · 18 minWith a plan

11Tags and publicationSeparate local release references from published registry references.4 exercises · 18 minWith a plan

Practice setBuild and distribution practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Intermediate

Local service stacks

Connect local services with networks, healthchecks, and Compose.

5 lessons

13Container network membershipAttach or detach a named process from a user-defined bridge.4 exercises · 18 minWith a plan

14Container healthchecksRead health as a separate signal from process state.4 exercises · 18 minWith a plan

15Compose service stacksStart and remove a declared stack while preserving its named data.4 exercises · 18 minWith a plan

ProjectMedia preview stackA media producer needs a repeatable preview environment with a web process and a cache.With a plan

Practice setLocal service stacks practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Cluster application basics

Deploy applications and expose ready Pods through stable Services.

4 lessons

18Pod resource definitionsRead metadata and container configuration in a Pod manifest.4 exercises · 18 minWith a plan

19Deployments and replicasSet the desired application count through a workload controller.4 exercises · 18 minWith a plan

20Service types and selectorsExpose selected ready Pods through the correct Service boundary.4 exercises · 18 minWith a plan

Practice setCluster application basics practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Application configuration

Isolate namespaces and connect ordinary settings and Secrets to workloads.

6 lessons

22Namespace identityKeep resources and command defaults in the requested team namespace.4 exercises · 18 minWith a plan

23ConfigMap configurationStore string settings separately and reference them from a workload.4 exercises · 18 minWith a plan

24Secret referencesCreate fictional credentials and consume the exact Secret key.4 exercises · 18 minWith a plan

Case studyScheduling API crash loopA fictional appointment API repeatedly restarts even though its Pod is scheduled.With a plan

Case studyRetail image pull failureA fictional retail preview never starts after a release reference changes.With a plan

Practice setApplication configuration practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Advanced

Health and capacity

Use probes and resource evidence to diagnose unhealthy or unscheduled Pods.

5 lessons

28Readiness, liveness and startupChoose a health signal with the right traffic or restart effect.4 exercises · 18 minWith a plan

29Requests and limitsSeparate scheduler reservations from runtime resource bounds.4 exercises · 18 minWith a plan

30Pending and memory failuresRepair the resource boundary that causes the observed workload failure.4 exercises · 18 minWith a plan

Case studyTravel worker schedulingA fictional travel worker remains Pending while its team waits for a scheduled export.With a plan

Practice setHealth and capacity practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Release and routing

Update releases and trace application traffic through Services and Ingress.

5 lessons

33Updates and rollback historyChange a Pod template and recover a previous working revision.4 exercises · 18 minWith a plan

34Service reachability diagnosisTrace a stable Service address through selectors and application ports.4 exercises · 18 minWith a plan

35Ingress HTTP routingConnect a host and path rule to an existing Service.4 exercises · 18 minWith a plan

Case studyLogistics service outageA logistics service exists, and its application Pods are running, but the stable address has no useful backend.With a plan

Practice setRelease and routing practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Persistent and scheduled work

Connect persistent storage and configure finite or scheduled workloads.

5 lessons

38Persistent claims and mountsBind storage independently and connect it through a Pod volume.4 exercises · 18 minWith a plan

39Finite JobsConfigure successful batch work with explicit completion and retry behavior.4 exercises · 18 minWith a plan

40CronJob schedulesDeclare scheduled finite work and control overlapping runs.4 exercises · 18 minWith a plan

ProjectPayments release workspaceA payments release needs a complete application boundary, not just one running Pod.With a plan

Practice setStorage and batch practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Expert

Release image design

Build smaller release images and reduce unnecessary runtime privileges.

5 lessons

43Multi-stage release imagesCopy selected artifacts into a separate runtime stage.4 exercises · 18 minWith a plan

44Build context hygieneExclude unwanted inputs before COPY reads the build context.4 exercises · 18 minWith a plan

45Runtime privilege boundariesSet image identity and Pod privileges without embedding credentials.4 exercises · 18 minWith a plan

Interview setBackend container interviewExplain a container boundary and produce a checked operational result.With a plan

Practice setRelease image design practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Pod and traffic design

Coordinate container initialization, shared storage, and selected network traffic.

6 lessons

48Multi-container Pod designShare data intentionally between a service and a supporting container.4 exercises · 18 minWith a plan

49Initialization orderComplete setup work before the main application starts.4 exercises · 18 minWith a plan

50Selected traffic policiesDescribe destination Pods and permitted sources without reversing selectors.4 exercises · 18 minWith a plan

ProjectHealthcare batch platformA healthcare scheduling team needs a batch workspace with persistent output and limited privileges.With a plan

Interview setPlatform operations interviewExplain a container boundary and produce a checked operational result.With a plan

Practice setPod and traffic design practiceCombine the unit's skills on a fresh set of original operational requests.With a plan

Platform decisions

Validate platform configuration and practice application developer assessments.

7 lessons

54Autoscaling prerequisitesConfigure a workload scaling target and identify its metrics dependencies.4 exercises · 18 minWith a plan

55Packages and platform boundariesChoose the correct deployment or control-plane mechanism for a stated need.4 exercises · 18 minWith a plan

56Manifest and platform checksValidate API versions, quotas, identities and rollout constraints.4 exercises · 18 minWith a plan

Interview setReliability engineering interviewExplain a container boundary and produce a checked operational result.With a plan

Mock examApplication developer mock oneComplete an original timed practical across application resources.With a plan

Mock examApplication developer mock twoComplete an original timed practical across application resources.With a plan

Practice setPlatform decisions practiceCombine the unit's skills on a fresh set of original operational requests.With a plan