I have a container A with Dockerfile as follows:
...
FROM ubuntu:latest
MAINTAINER arpitaggarwal "aggarwalarpit.89@gmail.com"
EXPOSE 8080
and another container B with Dockerfile as follows:
...
FROM ubuntu:latest
MAINTAINER arpitaggarwal "aggarwalarpit.89@gmail.com"
RUN apt-get install -q -y mysql-server
EXPOSE 3306
Then I started the container B using command:
docker run -P -it --name db B /bin/bash
And running the command: docker run --rm --name web --link db A env
gives me below output:
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=a5dd66b72ca8
DB_PORT=tcp://172.17.0.2:3306
DB_PORT_3306_TCP=tcp://172.17.0.2:3306
DB_PORT_3306_TCP_ADDR=172.17.0.2
DB_PORT_3306_TCP_PORT=3306
DB_PORT_3306_TCP_PROTO=tcp
DB_NAME=/web/db
HOME=/root
Then I logged into container A and run the command: ping db
which gives me output:
PING db (172.17.0.2) 56(84) bytes of data.
64 bytes from db (172.17.0.2): icmp_seq=1 ttl=64 time=0.082 ms
64 bytes from db (172.17.0.2): icmp_seq=2 ttl=64 time=0.063 ms
64 bytes from db (172.17.0.2): icmp_seq=3 ttl=64 time=0.065 ms
64 bytes from db (172.17.0.2): icmp_seq=4 ttl=64 time=0.061 ms
64 bytes from db (172.17.0.2): icmp_seq=5 ttl=64 time=0.066 ms
And when I tried telnet command with port 3306, as follows:
telnet 172.17.0.2 3306
gives me output:
root@9b078c1fed82:/# telnet 172.17.0.2 3306
Trying 172.17.0.2...
telnet: Unable to connect to remote host: Connection refused
Any idea, how can I telnet linked container?
Any help will be appreciated!
MySQL usually only listens on 127.0.0.1 by default. You need to modify the my.cnf during build and set bind-address to 0.0.0.0. You could accomplish this with something like:
RUN sed -i -e"s/^bind-address\s*=\s*127.0.0.1/bind-address = 0.0.0.0/" /etc/mysql/my.cnf