2 Prerequisites This skill 1 Unlocked

Skill · Containers · Build and run containers

Describe and harden a multi-service application with Docker Compose: variables, networks, data, secrets, health, resources and variants

Describe a multi-service application in a compose.yaml and check what Compose will create with docker compose config, drive its lifecycle (up, stop, down, down -v) under a project name, control interpolation and the precedence of environment files, spread services over networks, some of them internal, keep a database's data across every recreation and grant a file secret to a single service while knowing its limits. Then make it reliable: declare a healthcheck and make a service or a migration wait with depends_on conditions, knowing that an unhealthy service is not restarted and that the client must retry; limit memory, CPU and processes and check the limit in the cgroup, recognise an OOMKilled container, choose a restart policy, know what it restarts and tune the grace period; assemble a base and named variants with -f, predict how they merge and clear an inherited key with !reset, reserve a service for a profile, find a project's files with docker compose ls and use docker compose watch.

Start lesson 1The Containers domain

• 8 lessons
• ~11 h 35 of reading
• 8 quizzes
• 0 proof lab

Lessons

How to learn it

8 lessons, about ~11 h 35, in program order. Each lesson ends with its quiz.

The program

8 lessons · ~11 h 35

Part 1 · Describe an application with Compose 4 lessons · ~5 h 10

1. 1Describe an application with Compose: a first stack· 65 min
2. 2Interpolation and environment files in Compose· 80 min
3. 3Organize the networks of a Compose stack· 85 min
4. 4Persist the data of a recreated stack· 80 min

Part 2 · Make a stack reliable 4 lessons · ~6 h 25

1. 5Inject secrets, and know their limits· 75 min
2. 6Startup, readiness and health· 120 min
3. 7Limit resources and restarts of a Compose stack· 85 min
4. 8Development and deployment: explicit variants· 105 min

Beyond the lessons

Assess, practise, pass the proof

Reading a lesson confirms nothing. A skill is confirmed by a passed quiz, practised in a guided lab, and put to the test by a challenge or a mission; an imported lab result is not verified by the site.

Assess yourself

8 quizzes

At the end of the lessons: passed at 70%, they confirm the skill.

Practice

9 guided labs

• Separate frontend and data networks with Compose
• Keep application data across Compose recreation
• Start and recreate a two-service Compose application
• Two variants from one base, and no dev mount left in deployment
• Resolve Compose variables without mixing environments
• Enforce Compose resource budgets on the engine
• Wait for readiness, not just a running container
• Grant a Compose secret only to its consumer
• Gate application startup on a successful migration

Proof

No proof

Neither a challenge nor a mission with a proof yet.

Around it

Who requires it, who teaches it

Required by

• Linux Administrator

Taught by

• Containers and Docker

Same block · Build and run containers

• Run containers, persist data and connect them
• Build an OCI image
• Operate and troubleshoot Docker containers: lifecycle, logs, inspection and daemon
• Secure the installation and the containers
• Publish an image to a registry: access token, tag and digest
• Operate and restore a Docker Compose stack: logs, saturation, backup, update and rollback

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