Docker : Use Docker Compose2025/08/08

	To Install Docker Compose, it's easy to configure and run multiple containers as a Docker application.
[1]	Install Docker Compose.

[root@dlp ~]#

curl -L https://github.com/docker/compose/releases/download/v2.37.3/docker-compose-$(uname -s)-$(uname -m) -o /usr/local/bin/docker-compose

[root@dlp ~]#

chmod 755 /usr/local/bin/docker-compose

[root@dlp ~]#

docker-compose --version

Docker Compose version v2.37.3

[2]	For example, Configure an application that has Web and DB services with Docker Compose.

# define Web service container

[root@dlp ~]#

vi Dockerfile

FROM quay.io/centos/centos:stream10
LABEL maintainer="ServerWorld <admin@srv.world>"

RUN dnf -y install nginx

EXPOSE 80
CMD ["/usr/sbin/nginx", "-g", "daemon off;"]

# define application configuration

[root@dlp ~]#

vi docker-compose.yml

services:
  db:
    image: docker.io/library/mariadb
    volumes:
      - /var/lib/containers/disk01:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: password
      MYSQL_USER: cent
      MYSQL_PASSWORD: password
      MYSQL_DATABASE: cent_db
    user: 0:0
    privileged: true
    ports:
      - "3306:3306"
  web:
    build: .
    ports:
      - "80:80"
    volumes:
      - /var/lib/containers/disk02:/usr/share/nginx/html
    privileged: true

# build and run

[root@dlp ~]#

docker-compose up -d


.....
.....

  Container root-web-1  Starting                                           
  Container root-db-1   Starting                                           
[+] Running 4/4br-2b65fd497827: port 1(veth4676f8d) entered blocking state
 ✓ web                   Built                                       
 ✓ Network root_default  Created                                     
 ✓ Container root-web-1  Started                                     
 ✓ Container root-db-1   Started

[root@dlp ~]#

docker ps

CONTAINER ID   IMAGE      COMMAND                  CREATED              STATUS              PORTS                                         NAMES
9af087938a78   mariadb    "docker-entrypoint.s..."   About a minute ago   Up About a minute   0.0.0.0:3306->3306/tcp, [::]:3306->3306/tcp   root-db-1
0c7ca7b2dd0f   root-web   "/usr/sbin/nginx -g ..."   About a minute ago   Up About a minute   0.0.0.0:80->80/tcp, [::]:80->80/tcp           root-web-1

# verify accesses

[root@dlp ~]#

mysql -h 127.0.0.1 -u root -p -e "show variables like 'hostname';"

Enter password:
+---------------+--------------+
| Variable_name | Value        |
+---------------+--------------+
| hostname      | 9af087938a78 |
+---------------+--------------+

[root@dlp ~]#

mysql -h 127.0.0.1 -u cent -p -e "show databases;"

Enter password:
+--------------------+
| Database           |
+--------------------+
| cent_db            |
| information_schema |
+--------------------+

[root@dlp ~]#

echo "Hello Docker Compose World" > /var/lib/containers/disk02/index.html

[root@dlp ~]#

curl 127.0.0.1

Hello Docker Compose World

[3]	Other basic operations of Docker Compose are follows.

# verify state of containers

[root@dlp ~]#

docker-compose ps

NAME         IMAGE                       COMMAND                  SERVICE   CREATED         STATUS         PORTS
root-db-1    docker.io/library/mariadb   "docker-entrypoint.s..."   db        3 minutes ago   Up 3 minutes   0.0.0.0:3306->3306/tcp, [::]:3306->3306/tcp
root-web-1   root-web                    "/usr/sbin/nginx -g ..."   web       3 minutes ago   Up 3 minutes   0.0.0.0:80->80/tcp, [::]:80->80/tcp

# show logs of containers

[root@dlp ~]#

docker-compose logs


.....
.....

db-1  | 2025-08-08  5:56:53 0 [Note] InnoDB: Buffer pool(s) load completed at 250808  5:56:53
db-1  | 2025-08-08  5:56:56 0 [Note] Server socket created on IP: '0.0.0.0'.
db-1  | 2025-08-08  5:56:56 0 [Note] Server socket created on IP: '::'.
db-1  | 2025-08-08  5:56:56 0 [Note] mariadbd: Event Scheduler: Loaded 0 events
db-1  | 2025-08-08  5:56:56 0 [Note] mariadbd: ready for connections.
db-1  | Version: '11.8.2-MariaDB-ubu2404'  socket: '/run/mysqld/mysqld.sock'  port: 3306  mariadb.org binary distribution

# run any commands inside a container
# container name is just the one set in [docker-compose.yml]

[root@dlp ~]#

docker-compose exec db /bin/bash

root@9af087938a78:/#
root@9af087938a78:/# exit 
exit

# stop application and also shutdown all containers

[root@dlp ~]#

docker-compose stop

[+] Stopping 0/2
   Container root-db-1   Stopping                                           
   Container root-web-1  Stopping                                           
[+] Stopping 1/2eth4676f8d (unregistering): left allmulticast mode
   Container root-db-1   Stopping                                           
[+] Stopping 1/2t-web-1  Stopped                                            
   Container root-db-1   Stopping                                           
 ✓ Container root-web-1  Stopped                                      
[+] Stopping 2/2ethc7c2012 (unregistering): left allmulticast mode
 ✓ Container root-db-1   Stopped                                      
 ✓ Container root-web-1  Stopped

# start a service alone in application
# if set dependency, other container starts

[root@dlp ~]#

docker-compose up -d web

[+] Running 0/1
   Container root-web-1  Starting                                           
[+] Running 1/1br-2b65fd497827: port 1(veth900258e) entered blocking state
 ✓ Container root-web-1  Started

[root@dlp ~]#

docker-compose ps

NAME         IMAGE      COMMAND                  SERVICE   CREATED          STATUS          PORTS
root-web-1   root-web   "/usr/sbin/nginx -g ..."   web       38 seconds ago   Up 37 seconds   0.0.0.0:80->80/tcp, [::]:80->80/tcp

# remove all containers in application
# if a container is running, it won't be removed

[root@dlp ~]#

docker-compose rm

? Going to remove root-db-1 Yes
[+] Removing 1/1
 ✓ Container root-db-1  Removed

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