Pass container IP across containers for config file
I’m new to Docker, and am attempting to create two containers, one for MySQL and one for my Node.js app, based on images from Docker’s HUB.
I’d like to connect my node app to the MySQL host.
For this, I’m planning to store informations about this host through environment variables in my config.yaml (used by node-config) for later use.
My question is : how could I pass the IP address of the MySQL container to my node.js app?
It is dynamically attributed, I vaguely know I can retrieve it with a command as
docker inspect $(docker ps -q) | grep '"IPAddress"', it may be a clue?
mysql: image: mysql:5.6 environment: - MYSQL_ROOT_PASSWORD=**** - MYSQL_DATABASE=database - MYSQL_USER=user - MYSQL_PASSWORD=**** volumes: - /data/mysql:/var/lib/mysql nodeapp: build: . environment: - MYSQL_USER=^^^^^ // will mirror the value up there, and so on - ... ports: - "80:3000" links: - mysql
app: port: 3000 db: host: "MYSQL_HOST" // How can this be dynamic ? port:"MYSQL_PORT" database: "MYSQL_DATABASE" user: "MYSQL_USER" password: "MYSQL_PASSWORD"
FROM node:0.10 ADD package.json /usr/src/package.json # Install app dependencies RUN cd /usr/src && npm install ADD . /usr/src WORKDIR /usr/src EXPOSE 3000 CMD npm start
One Solution collect form web for “Pass container IP across containers for config file”
When you run containers with docker-compose, it adds in every container in
/etc/hosts a dynamic line with the format
<dynamic ip> container_name
Thus, when you run
docker-compose up every container knows any other container by its name.
So, in your confing.yaml you have to change this line
host: "MYSQL_HOST" // How can this be dynamic ?
/etc/hosts you have the dynamic association between the hostname
mysql and the dynamic ip assigned by docker the the MySQL container.