Introduction to Docker and containerization for developers who want to improve their workflow.
"It works on my machine" - this sentence is the reason for ~30% of conflicts between developers and DevOps. Docker solves this. You package the application with its environment and it works the same everywhere.
83%
of companies use containerization in production (CNCF Survey 2024)
Docker in 60 seconds
Without Docker
- "Install Node 18... wait, 16... or 20"
- "I have a different PostgreSQL version"
- "Works on Windows, not on Linux"
- Every dev has different environment
- New developer setup = half a day
With Docker
- Versions defined in Dockerfile
- Database in container (same for everyone)
- Works everywhere Docker runs
- Identical environment for whole team
- Setup = `docker-compose up`
Basic concepts
Image
"Recipe" for a container
Immutable, read-only. Defines: base OS, installed packages, app code. Versioned, stored in registry (Docker Hub, ECR).
Container
Running image
Isolated process with own filesystem, network, PID namespace. You can have many containers from same image.
Dockerfile
Instructions for building image
Text file with steps: FROM (base image), COPY (copy files), RUN (execute commands), CMD (what to run).
Key commands
docker build
builds image from Dockerfile
docker run
runs a container
docker ps
lists containers
Want to implement Docker in your project?
We'll help configure environment, write Dockerfile and train your team on containerization basics.