How to connect to local MySQL server through Docker?

Question

This is more a general question for how to connect to local services through Docker. There's a similar question in a Github issue here that doesn't seem to have any resolution. What I'm really looking for is to be able to do development locally against my local development MySQL server, then once I'm ready to deploy, to test locally against a newly created deploy candidate docker image.

Ideally, both get settings from the same place as well, so I could put mysql_server: host_ip. This seems like a typical use case. Is anything like this currently possible?

I'm using Boot2Docker specifically with MySQL server running on my host mac's OS X Yosemite NOT in a container. Would be cool to have a more general answer for future readers though.

Answer 1

The Docker CLI docs give this solution (which assumes you are running on a Linux host with ):

Sometimes you need to connect to the Docker host from within your container. To enable this, pass the Docker host’s IP address to the container using the --add-host flag. To find the host’s address, use the ip addr show command.

The flags you pass to ip addr show depend on whether you are using IPv4 or IPv6 networking in your containers. Use the following flags for IPv4 address retrieval for a network device named eth0:

$ HOSTIP=`ip -4 addr show scope global dev eth0 | grep inet | awk '{print $2}' | cut -d / -f 1`
$ docker run  --add-host=docker:${HOSTIP} --rm -it debian

Then the name docker inside the container will map to the host's IP address. For your case, you could use docker run --add-host=mysql_server:$(hostip) ...

If using Boot2Docker, it sets up a mapping to the host at a predefined address, so on that platform the equivalent to the above is just the one command:

$ docker run  --add-host=docker:192.168.59.3 --rm -it debian