Docker : Use Docker Compose2019/04/25

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

root@dlp:~#

apt -y install docker-compose

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

# define WEB service container

root@dlp:~#

vi Dockerfile

FROM ubuntu
MAINTAINER ServerWorld <admin@srv.world>

RUN apt-get update
RUN apt-get -y install apache2

EXPOSE 80
CMD ["/usr/sbin/apachectl", "-D", "FOREGROUND"]

# define application configration

root@dlp:~#

vi docker-compose.yml

version: '3'
services:
  db:
    image: mariadb
    volumes:
      - /var/lib/docker/disk01:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: password
      MYSQL_USER: disco
      MYSQL_PASSWORD: password
      MYSQL_DATABASE: disco_db
    ports:
      - "3306:3306"
  web:
    build: .
    ports:
      - "80:80"
    volumes:
      - /var/lib/docker/disk02:/var/www/html

# buid and run

root@dlp:~#

docker-compose up -d

Creating network "root_default" with the default driver
Pulling db (mariadb:)...
latest: Pulling from library/mariadb
.....
.....
Creating root_db_1  ... done
Creating root_web_1 ... done

root@dlp:~#

docker ps

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                    NAMES
2e0bd14e979a        mariadb             "docker-entrypoint.s…"   15 seconds ago      Up 14 seconds       0.0.0.0:3306->3306/tcp   root_db_1
acdd1bfeaaf6        root_web            "/usr/sbin/apachectl…"   15 seconds ago      Up 13 seconds       0.0.0.0:80->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      | 2e0bd14e979a |
+---------------+--------------+

root@dlp:~#

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

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

root@dlp:~#

echo "Hello Docker Compose World" > /var/lib/docker/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                 Command               State           Ports
----------------------------------------------------------------------------
root_db_1    docker-entrypoint.sh mysqld      Up      0.0.0.0:3306->3306/tcp
root_web_1   /usr/sbin/apachectl -D FOR ...   Up      0.0.0.0:80->80/tcp

# show logs of containers

root@dlp:~#

docker-compose logs

Attaching to root_db_1, root_web_1
db_1   | Initializing database
.....
.....
db_1   | 2019-04-25  4:24:06 0 [Note] mysqld: ready for connections.
db_1   | Version: '10.3.14-MariaDB-1:10.3.14+maria~bionic'  socket: '/var/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@2e0bd14e979a:/#

# stop application and also shutdown all containers

root@dlp:~#

docker-compose stop

Stopping root_db_1  ... done
Stopping root_web_1 ... done

# start a service alone in application

# if set dependency, other container starts

root@dlp:~#

docker-compose up -d web

Starting root_web_1 ... done

root@dlp:~#

docker-compose ps

   Name                 Command               State          Ports
-------------------------------------------------------------------------
root_db_1    docker-entrypoint.sh mysqld      Exit 0
root_web_1   /usr/sbin/apachectl -D FOR ...   Up       0.0.0.0:80->80/tcp

# remove all containers in application

# if a container is running, it won't be removeds

root@dlp:~#

docker-compose rm

Going to remove root_web_1
Going to remove root_db_1
Are you sure? [yN] y
Removing root_db_1 ... done
Removing root_web_1 ... done

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