jverg/docker-workshop

1. Run a simple Docker container

What to do:

• Create a Debian container
• New Dockerfile
  • FROM debian
• Build image
• Run image
• Run cat /etc/issue

Hints:

• docker build . -t [IMAGE_NAME]
• docker run -it [IMAGE_NAME] bash

Solution

New Dockerfile

FROM debian

Build image

docker build . -t debian_image

Run image

docker run -it debian_image bash

Run inside the container now

cat /etc/issue

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2. Create a Docker container and mount host volume

What to do:

• Create a Debian container (Dockerfile bluh bluh)
• Create a folder “html”
• Create inside folder an index.html file
• With some text
• Mount host folder ./html to /html folder in container

Hints:

• "--mount type=bind,source="$(pwd)/html",target=/html"

Solution

New Dockerfile

FROM debian

Create folder and HTML file

mkdir html
touch html/index.html
echo "Hello SocialNerds!" >> html/index.html

Build image

docker build . -t debian_image

Run image

docker run -it --mount type=bind,source="$(pwd)/html",target=/html ubuntu_image bash

Run inside the container now

cat /html/index.html

You should see "Hello SocialNerds!"

3. Create a Docker container with named volume

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What to do:

• Create a Debian container (Dockerfile bluh bluh)
  • named debian_1
• Create a volume named “html”
• Mount volume “html” to /html folder in container
• Add a new file named “index.html” in /html folder
• Create a new Debian container named debian_2
• Mount volume “html” to /html folder in container

Hints:

• docker volume create [VOLUME_NAME]
• --mount source=[VOLUME_NAME],target=/html
• --name [CONTAINER_NAME]

Solution

New Dockerfile

FROM debian

Create volume

docker volume create html

Build image

docker build . -t debian_image

Run image

docker run -it --name debian_1 --mount source=html,target=/html ubuntu_image bash

Run inside the container now

touch /html/index.html

Exit the container

exit

Run another container

docker run -it --name debian_2 --mount source=html,target=/html ubuntu_image bash

Check file exists

ls -la /html/index.html

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4. Create a network for all services

What to do:

• Run ./clearall
• Go to 4_Network folder (cd 4_Network)
• Run ./setall
• Run "docker ps" to check everything is there
• Create a network named apache_tomcat_mysql
• Connect all containers to it
• Connect mysql container with "superdb" alias

Hints:

• docker network connect [NETWORK_NAME] [CONTAINER_NAME]
• docker network connect --alias [ALIAS] [NETWORK_NAME] [CONTAINER_NAME]

Solution

Create network

docker network apache_tomcat_mysql

Connect all to network

docker network connect apache_tomcat_mysql apache
docker network connect apache_tomcat_mysql tomcat
docker network connect --alias superdb apache_tomcat_mysql mysql

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5. RUN MySQL with more environment variables

What to do:

• Run ./clearall
• Run a MySQL 5.7 container and pass environment variables for
  • MYSQL_ROOT_PASSWORD
  • MYSQL_DATABASE (Creates a database by default)
  • MYSQL_USER (Creates a user for the default database)
  • MYSQL_PASSWORD (Sets a password for this user)

Hints:

• "-e MYSQL_ROOT_PASSWORD=[MYSQL_ROOT_PASSWORD]"

Solution

Run MySQL container

docker run -d -e MYSQL_ROOT_PASSWORD=root \
  -e MYSQL_DATABASE=my_default_database \
  -e MYSQL_USER=my_default_user \
  -e MYSQL_PASSWORD=password \
  mysql:5.7

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6. RUN MySQL with environment variables from file

What to do:

• Run ./clearall
• Create a new folder and cd to this folder
• Run a MySQL 5.7 container and pass environment variables through an .env file for
  • MYSQL_ROOT_PASSWORD
  • MYSQL_DATABASE (Creates a database by default)
  • MYSQL_USER (Creates a user for the default database)
  • MYSQL_PASSWORD (Sets a password for this user)

Hints:

• "--env-file .env"

Solution

Create file and add variables

touch .env
echo "MYSQL_ROOT_PASSWORD=root\n\
MYSQL_DATABASE=my_default_database\n\
MYSQL_USER=my_default_user\n\
MYSQL_PASSWORD=password\n" \
> .env

Run MySQL container

docker run -d --env-file .env mysql:5.7

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7. COPY, CMD

What to do:

• Run ./clearall
• Create a new folder and cd to this folder
• Create Dockerfile and a "start" script
• In the start script add the command "tail -f /dev/null"
• Create a Dockerfile "FROM ubuntu"
• In the Dockerfile create a user named "serveruser"
• COPY the script inside the Docker image under /home/serveruser/
• Set the owner of the start script as "serveruser"
• Make the start script the default command

Hints:

• Create user "RUN useradd -ms /bin/bash [USERNAME]"
• Add execute permission "RUN chmod +x [FILE]"
• Copy from host to image "COPY [HOST_SOURCE] [IMAGE_DESTINATION]"
• Script annotation "#!/bin/bash"
• Default command "CMD [COMMAND]"

Solution

Dockerfile

FROM ubuntu

RUN useradd -ms /bin/bash serveruser

COPY ./start /home/serveruser/start
RUN chmod +x /home/serveruser/start
RUN chown serveruser:serveruser /home/serveruser/start

CMD ["/home/serveruser/start"]

Start script

#!/bin/bash

tail -f /dev/null

Build image

docker build . -t ubuntu_image

RUN image

docker run -d ubuntu_image

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8. ARG

What to do:

• Run ./clearall
• Create a Dockerfile "FROM ubuntu"
• In the Dockerfile create a user named "serveruser"
• Build the image UID=512 for "serveruser"

Hints:

• Create user "RUN useradd -ms /bin/bash -u [UID] [USERNAME]"
• Dockerfile syntax "ARG [ARGUMENT]"
• Command "--build-arg UID=[UID]"

Solution

Dockerfile

FROM ubuntu

ARG UID

RUN useradd -ms /bin/bash -u $UID serveruser

Build image

docker build . --build-arg UID=512 -t ubuntu_image

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9. docker-entrypoint

What to do:

• Run ./clearall
• cd to 9_Docker_Entrypoint folder
• When docker-entrypoint.sh runs, create a new folder /home/serveruser/code
• This new folder must be owned by user "serveruser"
• The name of the folder must pass as env variable E.g. "CODE_FOLDER"

Hints:

• Create folder: "mkdir /home/serveruser/[FOLDER_NAME]"
• Change ownsership "chown -R [USERNAME]:[GROUP] /home/serveruser/[FOLDER_NAME]"

Solution

docker-entrypoint.sh

###
mkdir /home/serveruser/$CODE_FOLDER
chown -R serveruser:serveruser /home/serveruser/$CODE_FOLDER
###

Build image

docker build . -t ubuntu_image

Run image

docker run -d --name ubuntu_container -e UID=512 -e CODE_FOLDER=code ubuntu_image

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10. Docker Compose

What to do:

• Run ./clearall
• cd to 10_Docker_Compose folder
• Add a new service named app_http_2
• Add to the same network as app_http
• No exposed ports
• Same command
• Same volume

Hints:

• What hints? It is just copy paste :)
• Build images: docker-compose build
• Run images: docker-compose up -d
• Stop and Remove: docker-compose down

Solution

docker-compose.yml

http_2:
  image: ubuntu:18.04
  command: ["tail", "-f", "/dev/null"]
  container_name: app_http_2
  volumes:
    - ./data:/data
  networks:
    app_network:

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11. Docker Compose env

What to do:

• Run ./clearall
• cd to 11_Docker_Compose_env folder
• Pass an environment variable to fpm service named APP_DEBUG
• The value of the variable should be "TRUE"

Hints:

• Don't forget to add the variable in the .env file

Solution

docker-compose.yml

environment:
  APP_DEBUG: ${APP_DEBUG}

.env

###
APP_DEBUG=TRUE
###

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12. Docker Compose args

What to do:

• Run ./clearall
• cd to 12_Docker_Compose_args folder
• Pass an argument to fpm service named UID
• The value of the variable should be the user id of your user on your machine

Hints:

• Type "id" to get user id
• Google "docker compose arguments"

Solution

docker-compose.yml

fpm:
  build:
    context: ./fpm
    args:
      UID: ${UID}
  container_name: fpm
  .....

.env

UID=1234

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13. Docker Compose networks

What to do:

• Run ./clearall
• cd to 13_Docker_Compose_networks folder
• Set a network for http and fpm named app_public_network
• Set a network for fpm and db named app_private_network

Solution

docker-compose.yml

version: '3.8'

services:
  http:
    build:
      context: ./http
      args:
        UID: ${UID}
    container_name: http
    restart: always
    volumes:
      - ./code:/home/serveruser/code
    ports:
      - 8080:80
    networks:
      app_public_network:
  fpm:
    build:
      context: ./fpm
      args:
        UID: ${UID}
    container_name: fpm
    restart: always
    volumes:
      - ./code:/home/serveruser/code
    networks:
      app_private_network:
      app_private_network:
  db:
    build:
      context: ./db
    container_name: db
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
      MYSQL_DATABASE: ${MYSQL_DATABASE}
      MYSQL_USER: ${MYSQL_USER}
      MYSQL_PASSWORD: ${MYSQL_PASSWORD}
    volumes:
      - dbdata:/var/lib/mysql
    networks:
      app_private_network:

networks:
  app_public_network:
  app_private_network:

volumes:
  dbdata:

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14. Docker Compose override

What to do:

• Run ./clearall
• cd to 14_Docker_Compose_override folder
• Create a new file docker-compose-dev.yml
• Add to docker-compose-dev.yml only the db service configuration
• Remove the db service configuration from docker-compose.yml

Solution

docker-compose-dev.yml

version: '3.8'

services:
  db:
    build:
      context: ./db
    container_name: db
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
      MYSQL_DATABASE: ${MYSQL_DATABASE}
      MYSQL_USER: ${MYSQL_USER}
      MYSQL_PASSWORD: ${MYSQL_PASSWORD}
    volumes:
      - dbdata:/var/lib/mysql
    networks:
      app_network:

volumes:
  dbdata:

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