Wordpress can't see linked mysql container on IBM Bluemix with Docker compose - docker

Question

I have a simple docker-compose.yml (wp image is based on ibmjstart/wp-bluemix-container, db image is mariadb)
db:
image: registry.eu-gb.bluemix.net/foo/db
environment:
MYSQL_ROOT_PASSWORD: examplepass
ports:
- 3306:3306
volumes:
- /var/lib/mysql
wp:
image: registry.eu-gb.bluemix.net/foo/wp
links:
- db:mysql
ports:
- 80:80
after executing docker compose up -d I get
error: missing WORDPRESS_DB_HOST and MYSQL_PORT_3306_TCP environment variables
Did you forget to --link some_mysql_container:mysql or set an external db
with -e WORDPRESS_DB_HOST=hostname:port?
As you can see, the db container is linked.
When I do the same without docker-compose, using
$ cf ic run -v mysql-vol:/var/lib/mysql --name wpdb -d registry.eu-gb.bluemix.net/foo/db
$ cf ic run -e MYSQL_ROOT_PASSWORD=my-secret-pw -v web-files:/var/www/html/ --link wpdb:mysql -d registry.eu-gb.bluemix.net/foo/wp
Everything works well.
I do export docker variables after cf ic login
More info:
root#vps:~/test/compose# docker-compose --version
docker-compose version 1.7.0, build 0d7bf73
root#vps:~/test/compose# docker --version
Docker version 1.10.3, build 20f81dd
root#vps:~/test/compose# cf --version
cf version 6.15.0+fa1bfe2-2016-01-13
root#vps:~/test/compose# cf ic --version
Docker version 1.10.3, build 20f81dd
UPDATE: As I understand, this problem is caused by the naming:
This docker-compose.yml throws an error
db:
image: registry.eu-gb.bluemix.net/foo/db
environment:
MYSQL_ROOT_PASSWORD: examplepass
container_name:
wpdb
ports:
- 3306:3306
volumes:
- /var/lib/mysql
wp:
image: registry.eu-gb.bluemix.net/foo/wp
links:
- wpdb:mysql
ports:
- 80:80
ERROR: Service "wp" has a link to service "wpdb" which does not exist.
However, if you name the service and container the same, the syntax is ok.
db:
image: registry.eu-gb.bluemix.net/foo/db
environment:
MYSQL_ROOT_PASSWORD: examplepass
container_name:
db
ports:
- 3306:3306
volumes:
- /var/lib/mysql
wp:
image: registry.eu-gb.bluemix.net/foo/wp
links:
- db:mysql
ports:
- 80:80
Although the syntax is OK and the container is linked, the wordpress container logs this
Warning: mysqli::mysqli(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: Name or service not known in - on line 10
MySQL Connection Error: (2002) php_network_getaddresses: getaddrinfo failed: Name or service not known
Is this a bug in Bluemix? Looks like a /etc/hosts/ related problem
Sorry for a long post :)

Answer 1

#bartimar Yes, the problem is related to the /etc/hosts file. It needs to have an entry for the db container, but it is not creating it.
I can recreate your problem in the prod-lon02-vizio1 environment, but it works fine in the prod-lon02-kraken1 environment.
My recommendation if for you to manually migrate to the prod-lon02-kraken1 environment to use docker-compose.yml with IBM containers. All environments will be automatically migrated on May 25th anyway.
To migrate simply run the following command:
$ cf ic reprovision
Please note that your images are migrated to new environment, but all your running containers are deleted and you will have to recreate them in the new environment. So use this option with caution.
For more details check the link below:
https://developer.ibm.com/bluemix/2016/03/24/new-deployment-architecture-for-containers/?linkId=22660520