Running App in Docker (2)
Sat 08 September 2018
Docker Compose
docker run can be tedious sometimes if you have a lot of parameters to pass in or you need to re-run the container multiple times.
Docker Compose is a tool that can help you run the commands via the definition in a yml file. We call the .yml file as "docker-compose file".
YAML is a human friendly data serialization standard for all programming languages.
Example
Our example in last post can fit into a "docker-compose" file:
version: '3'
services:
rabbit-mq:
image: rabbitmq:management-alpine
container_name: dev-rabbitmq
restart: always
ports:
- 15672:15672
- 5672:5672
You can always find a corresponding config in the file for your docker run command. Then you can start your RabbitMQ with a very few command.
$ docker-compose up -d
More complicated, we can build serveral services together into one "docker-compose" file:
version: '3'
services:
redis:
image: redis:alpine
container_name: dev-redis
restart: always
ports:
- 6379:6379
networks:
- devnet
rabbit-mq:
image: rabbitmq:management-alpine
container_name: dev-rabbitmq
restart: always
ports:
- 15672:15672
- 5672:5672
networks:
- devnet
couch-db:
container_name: dev-couchdb
image: klaemo/couchdb:latest
restart: always
volumes:
- ./couchdb/local:/opt/couchdb/etc/local.d
- ./couchdb/data:/opt/couchdb/data
ports:
- 5984:5984
networks:
- devnet
networks:
devnet:
In the above docker-compose file, it also defines a "network" for the containers so that those containers are isolated from other containers.
Save the configs into a text file named docker-compose.yml. Then you can start all the containers together via the command:
$ docker-compose up --detach
It will auto load the docker-compose.yml file and start the containers for you. You can also use parameter -f to specify a docker-compose file:
$ docker-compose up \
-f docker-compose.yml \
-d
Category: Container