beginner

Discover Docker: The Beginner’s Journey

Docker Container

Run a container of image docker/welcome-to-docker without exposing port, detach

docker run docker/welcome-to-docker

Run a container of image docker/welcome-to-docker

docker run -d -p 8080:80 --name welcome docker/welcome-to-docker

• -d: it will run the container in the background instead (alias --detach)
• -p <HOST_PORT>:<CONTAINER_PORT>: expose its ports. -p 8080:80 Now, any traffic sent to port 8080 on your host machine will be forwarded to port 80 within the container.
• --name <NAME>: Custom Container Name
• docker/welcome-to-docker: Image name

See Last 10 lines log and follow

docker logs welcome
docker logs -f --tail 10 welcome

• -f: follow
• --tail n: show latest n lines

Execute command on the container

docker exec welcome cat /usr/share/nginx/html/index.html

Execute an interactive sh shell on the container

docker exec -it welcome sh

Stop the container welcome

docker stop welcome

Building Image

Build Dockerfile to Image

cd go_sample
docker build --tag docker-go-ping .
docker build -t docker-go-ping -f Dockerfile.alpine .

# check the image is exists
docker image ls

Tag image

# tag latest docker-go-ping image
docker image tag docker-go-ping:latest docker-go-ping:v1.0

Run image to container

docker run -d -p 8080:8080 --name my-docker-go-ping-container docker-go-ping

Run Container with Persisting Data With Volumes (e.g., Database)

Create volume

docker volume create postgres-data

Run postgres with volume

# https://github.com/docker-library/docs/blob/master/postgres/README.md
docker run -d \
    --name postgres \
    --env POSTGRES_USER=postgres \
    --env POSTGRES_PASSWORD=password \
    --volume postgres-data:/var/lib/postgresql/data \
    --restart unless-stopped \
    --publish 5432:5432 \
    postgres

# If you're using git bash, add MSYS2_ENV_CONV_EXCL='*' MSYS2_ARG_CONV_EXCL='*' to avoid auto conversion from arguments and env
# https://www.msys2.org/docs/filesystem-paths/#environment-variables
MSYS2_ARG_CONV_EXCL='*' MSYS2_ENV_CONV_EXCL='*' docker run -d \
    --name postgres \
    --env POSTGRES_USER=postgres \
    --env POSTGRES_PASSWORD=password \
    --volume postgres-data:/var/lib/postgresql/data \
    --restart unless-stopped \
    --publish 5432:5432 \
    postgres

Run mySQL

docker run --name some-mysql -v some-mysql-data:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=password -d mysql

Docker Compose

Create and Start Docker Compose + Rebuild Image

docker compose up -d --build
docker compose -f docker-compose.yml up -d --build
docker compose -f docker-compose.alpine.yml up -d --build

Stop compose containers

docker compose stop
docker compose -f docker-compose.yml stop

Start stopped compose containers

docker compose start
docker compose -f docker-compose.yml start

Stop and Destroy Docker Compose Containers

docker compose down
docker compose -f docker-compose.yml down -d --build

Vue with Docker

npx create-vue vue_sample
cd vue_sample
npm install
code .
npm run dev


docker build -t vue_sample .
docker run -d -p 80:80 --name vue_sample vue_sample

Other Things

Syntax ENTRYPOINT vs CMD: https://spacelift.io/blog/docker-entrypoint-vs-cmd

• ENTRYPOINT is the process that’s executed inside the container.
• CMD is the default set of arguments that are supplied to the ENTRYPOINT process.

There are also differences in how you override these values when you start a container:

• CMD is easily overridden by appending your own arguments to the docker run command.
• ENTRYPOINT can be changed using the --entrypoint flag, but this should rarely be necessary for container images being used in the way they were intended. If you do change the ENTRYPOINT, you’ll almost certainly need to set a custom CMD too—as otherwise, your new ENTRYPOINT is likely to receive arguments that it doesn’t understand.