Docker compose is similar to vagrant. It is automation for containers. Let’s say if we have to create multiple containers, as of now we have to issue multiple commands. Or let’s say we want to provide -v, -e and many others, if would be difficult to handle this long command. At that point docker compose comes in handy where we create a .yml file and executes it. And that’s all.
The real power of docker compose comes with docker swarm.
We can create multiple containers using docker compose and those containers are linked together.
Let’s install docker compose now
sudo curl -L "https://github.com/docker/compose/releases/download/1.24.1/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose
ubuntu@ip-172-31-5-45:~$ docker-compose --help
Let’s create a docker compose file
docker-compose.yml
version: '3'
services:
xxxnginx:
image: xxx/xx
ports:
- "80:80"
xxxapp:
image: xx/xx
ports:
- "8080:8080"
xxxdb:
image: xx/xx
ports:
- "3306:3306"
environment:
- MYSQL_ROOT_PASSWORD=xxxTo run this yaml file give the command. It will pull the images and will execute the instructions.
docker-compose up => to run it in foreground
docker-compose up -d => to run it in background
docker-compose will create its own network
NETWORK ID NAME DRIVER SCOPE
a884949f360a bridge bridge local
c0f546cebf26 compose_default bridge local
d63bc051aa8d host host local
9a2b1d66736f my-net bridge localApplication would be up and running, all the request would be going to IP:80(nginx) and it would be routing the request to the tomcat and all the containers(nginx,tomcat,db) would be linked to each other.
To see the running containers
ubuntu@ip-172-31-5-45:~/compose$ docker-compose ps
Name Command State Ports
---------------------------------------------------------------------------------------------
compose_xxxapp_1 catalina.sh run Up 0.0.0.0:8080->8080/tcp
compose_xxxdb_1 docker-entrypoint.sh mysqld Up 0.0.0.0:3306->3306/tcp, 33060/tcp
compose_xxxnginx_1 nginx -g daemon off; Up 0.0.0.0:80->80/tcp
Similarly, you can execute many commands using docker-compose(mentioned above using –help)
