Challenge - Compose

Combine web and database with compose.

Challenge: a Compose stack

WordPress + MySQL is the classic Compose example. In this challenge you'll define a two-service stack in a single file: the database will persist in a named volume, WordPress will connect to the database by service name, and only WordPress will publish a port.

services:
  db:
    image: mysql:8
    environment:
      MYSQL_ROOT_PASSWORD: gizli
      MYSQL_DATABASE: wp
    volumes:
      - dbveri:/var/lib/mysql
  wordpress:
    image: wordpress:6
    ports:
      - "8080:80"
    environment:
      WORDPRESS_DB_HOST: db
      WORDPRESS_DB_PASSWORD: gizli
    depends_on:
      - db
volumes:
  dbveri:

Exercise compose.yaml

Write the compose.yaml from the card: the db service (mysql:8, MYSQL_ROOT_PASSWORD: gizli, dbveri:/var/lib/mysql); the wordpress service (wordpress:6, "8080:80", WORDPRESS_DB_HOST: db, db under depends_on); dbveri: under a top-level volumes.

Show example solution

# compose.yaml
services:
  db:
    image: mysql:8
    environment:
      MYSQL_ROOT_PASSWORD: gizli
    volumes:
      - dbveri:/var/lib/mysql
  wordpress:
    image: wordpress:6
    ports:
      - "8080:80"
    environment:
      WORDPRESS_DB_HOST: db
    depends_on:
      - db

volumes:
  dbveri:

Exercise Manage the stack

Write three commands: start the stack in the background; show the status of the services; follow the logs of the wordpress service live.

Show example solution

docker compose up -d
docker compose ps
docker compose logs -f wordpress

Test yourself

Why does WORDPRESS_DB_HOST take the value db?
- db is an IP address
- It's MySQL's default name
- It was chosen arbitrarily
- On the Compose network, the service name is the DNS name
Show answer

On the Compose network, the service name is the DNS name — Containers find each other by name on the shared default network.
Start the stack in the background.
```
docker compose up ____
```
Show answer
```
docker compose up -d
```
Match.

dbveri

Persistent MySQL data
8080:80

Only WordPress published
depends_on

Start order
WORDPRESS_DB_HOST: db

Connection by service name

Next lesson: Challenge - Beginner project

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