CodeBlanks Logo Icon CodeBlanks
Login Register

Use cases

Learn common Docker use cases.

Use cases

Docker's most common uses:

  • Development environment: starting services like PostgreSQL and Redis with one command, without installing them.
  • CI/CD: running tests every time in a clean, identical environment.
  • Microservices: deploying each service independently in its own container.
  • Portable deployment: running the same image on different cloud providers.
docker run -d -e POSTGRES_PASSWORD=gizli -p 5432:5432 postgres:16

Throwaway tools

Docker is also ideal for using a tool once without installing it on the machine. The --rm flag deletes the container automatically when its work is done:

docker run --rm python:3.12 python -c "print(2 ** 10)"
# 1024
docker run --rm -v "$PWD":/app -w /app node:20 npm test

This way different Python or Node versions can be used for different projects without mixing.

Practice One-off Python

Write the command that runs python -c "print(2 ** 10)" in the python:3.12 image and deletes the container when done.

Starter code

terminal
# buraya yaz

Expected output

1024

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What is the main benefit of running tests inside a container in a CI pipeline?

  • Tests never failing
  • A clean, identical environment on every run Correct answer
  • Tests containing less code
  • Not needing an internet connection

Explanation: Leftover files from earlier runs or different versions don't affect the result.

2 Delete the container automatically when it finishes.

Question 
docker run ____ python:3.12 python -c "print(1)"
Answer 
docker run --rm python:3.12 python -c "print(1)"

Explanation: --rm removes the container when it exits.

3 Match the scenarios.

Term Meaning
local database docker run postgres
CI tests Clean environment
microservice A container per service
--rm One-off tool

All lessons in Beginner

1 What is Docker?

  1. What is Docker?
  2. Containers and virtual machines
  3. Images and containers
  4. Docker architecture
  5. Use cases
  6. Summary - What is Docker

2 Installation and first commands

  1. Installing Docker
  2. docker version
  3. docker info
  4. The hello-world container
  5. Docker Desktop
  6. Summary - Installation

3 First container

  1. docker run basics
  2. Running in the background
  3. docker ps
  4. docker stop and rm
  5. docker logs
  6. Summary - First container

4 Dockerfile basics

  1. What is a Dockerfile?
  2. The FROM instruction
  3. The RUN instruction
  4. COPY and ADD
  5. CMD and ENTRYPOINT
  6. Summary - Dockerfile

5 Build and images

  1. docker build
  2. Tagging images
  3. Build context
  4. Layers and cache
  5. .dockerignore
  6. Summary - Build

6 docker run options

  1. Interactive mode
  2. Naming containers
  3. Restart policy
  4. Working directory
  5. Switching users
  6. Summary - docker run

7 Image management

  1. docker images
  2. docker rmi
  3. docker pull
  4. docker push
  5. docker tag
  6. Summary - Image management

8 Port mapping

  1. The port concept
  2. The -p flag
  3. Multiple ports
  4. Random ports
  5. IP binding
  6. Summary - Port mapping

9 Volumes and data

  1. Data persistence
  2. Named volumes
  3. The -v flag
  4. Bind mounts
  5. Volume management
  6. Summary - Volumes

10 Environment variables

  1. The -e flag
  2. The ENV instruction
  3. The ARG instruction
  4. env-file
  5. The WORKDIR instruction
  6. Summary - Environment

11 Project: docker-compose

  1. Compose design
  2. Service definition
  3. Database service
  4. Volume and network
  5. Putting it together - compose

12 Docker Hub and registry

  1. What is Docker Hub?
  2. docker login
  3. Searching images
  4. Official images
  5. Private registry
  6. Summary - Registry

13 Network basics

  1. Network drivers
  2. docker network ls
  3. Bridge network
  4. Container connectivity
  5. Publishing ports
  6. Summary - Network

14 Beginner final

  1. Challenge - Dockerfile
  2. Challenge - Build and run
  3. Challenge - Volume
  4. Challenge - Compose
  5. Challenge - Beginner project