Listing 6. Linking containers in the same server is done via /etc/hosts
entries.

# su -
# docker exec -it MYWEB bash
root@fbff94177fc7:/var/www/html# cat /etc/hosts
172.17.0.3     fbff94177fc7
127.0.0.1      localhost
...
172.17.0.2     MYDB

root@fbff94177fc7:/var/www/html# export
declare -x MYDB_PORT="tcp://172.17.0.2:3306"
declare -x MYDB_PORT_3306_TCP="tcp://172.17.0.2:3306"
declare -x MYDB_PORT_3306_TCP_ADDR="172.17.0.2"
declare -x MYDB_PORT_3306_TCP_PORT="3306"
declare -x MYDB_PORT_3306_TCP_PROTO="tcp"
...