Chapter 6: Docker Images and Containers

6.7 Environment variables at run time

By Ravindra Bagale · Last updated: 1 October 2026

Pass config when you start the container — do not bake production secrets into the image.

docker run -d --name badge-api \
  -p 8080:8080 \
  -e APP_ENV=lab \
  -e APP_URL=http://0.0.0.0:8080 \
  badge-api-hello:0.1

For files of variables, -env-file can work for labs — keep that file gitignored like .env.