Docker là gì? Frontend developer cần biết gì về Docker?

Docker đóng gói ứng dụng và dependencies vào container, đảm bảo chạy giống nhau trên mọi máy (dev, staging, production).

Frontend dev cần biết:

1. Dockerfile multi-stage — stage 1 build app, stage 2 chỉ copy file build sang nginx/node, giảm image từ 1GB xuống ~100MB.
2. docker-compose.yml để chạy frontend + backend + database cùng lúc bằng docker-compose up.
3. .dockerignore loại node_modules và .next tránh copy file thừa

Lưu ý quan trọng: environment variables phải inject lúc runtime (docker run -e), không hardcode vào image vì image dùng chung cho nhiều môi trường.

Docker packages an application and its dependencies into a container, ensuring it runs identically across all environments (dev, staging, production).

Frontend devs should know:

1. Multi-stage Dockerfile — stage 1 builds the app, stage 2 copies only the build output into nginx/node, shrinking the image from 1GB to ~100MB.
2. docker-compose.yml to run frontend + backend + database together with docker-compose up.
3. .dockerignore to exclude node_modules and .next to avoid copying unnecessary files

Critical note: environment variables must be injected at runtime (docker run -e), not hardcoded into the image, since one image serves multiple environments.