Docker, from the ground up

A no-login Docker course with interactive artifacts, from-scratch builds, and break-fix scenarios that grow TaskFlow Lab from a simple app into a production-ready container system.

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Sample Artifact

The Resource Limiter Simulator

Visualize how cgroups enforce resource limits on containers

Sample Exercise

The API That Starts Before the Database Is Ready

Type: Break-fix · Repair a Compose startup race

Scenario

The API exits before Postgres is ready.

TaskFlow Lab has moved to Docker Compose. A teammate added depends_on: db and expected the API to wait for Postgres. The containers start in order, but Postgres is still initializing. The API connects too early, gets connection refused, and exits.

api | failed to connect to taskflow-db:5432

Your tasks

Reproduce the API startup failure
Explain why depends_on controls order, not readiness
Add a Postgres healthcheck and service_healthy condition
Verify the API starts cleanly after the database is ready

Hint

Start order is not readiness. Compose can wait for a service to become healthy, but only after the database defines a healthcheck.

Curriculum

The complete learning path

Take the modules in order. The regular curriculum builds the Docker model from first principles; the final project applies it as a separate capstone system.

Docker, from the ground up

How the course teaches Docker

The Resource Limiter Simulator

The API That Starts Before the Database Is Ready

The API exits before Postgres is ready.

The complete learning path