Connecting to MySQL Server on localhost through Docker

Question

So, I'm able to generally contact my localhost through Docker by running a container with --add-host=localbox:192.168.59.3. ping localbox works just fine. Problem is, I can't seem to be able to even get a response from MySQL Server. mysql -h localbox, which works fine from outside of the docker container, just gets me ERROR 2003 (HY000): Can't connect to MySQL server on 'localbox' (111) from within.

I've done GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'password' WITH GRANT OPTION;

I've added bind-address = 0.0.0.0 into /etc/my.cnf. None of this helps. What gives?

Context: I'm running all of this through boot2docker on OS X Yosemite.

Grand

It seems that localbox is not recognized as a valid host name. What does it happen if you use the IP address instead of localbox from within the container? – Statesmanship

localbox is a valid hostname. Like I said, pinging localbox works fine. – Grand

Do you mean pinging it from within the container? – Statesmanship

Yes. Everything I mention aside from running the container and modifying mysql server configs, I'm doing from within the container. – Grand

What do you get running netstat? Is MySQL listening? – Statesmanship

Yes. Through lsof -i 3306, I see localhost:mysql (LISTEN) (on localhost) – Grand

What about mysql -h localhost? Does it work? Which command do you use to run MySQL? – Statesmanship

Let us continue this discussion in chat. – Grand

Answer 1

So, turns out this is homebrew's fault with a really questionable design decision. You start-up mysql-server in homebrew by running the recommended launchctl load -w ~/Library/LaunchAgents/homebrew.mxcl.mysql.plist. But then, when examining this file, you'll find the bind-address is hardcoded!

  <array>
    <string>/usr/local/opt/mysql/bin/mysqld_safe</string>
    <string>--bind-address=127.0.0.1</string>
    <string>--datadir=/usr/local/var/mysql</string>
  </array>

So, no matter what you do in any of your my.cnf files, it will always be bound to 127.0.0.1, and you'll never be able to query from a container. My fix is just editing this file directly not to provide a bind address so we can let /etc/my.cnf do it for us. Alternatively, though I wouldn't recommend it, you can just change the bind-address directly in this file.

Grand

Answer 2

You can add the mac host's network to your docker container (running in boot2docker) with

--add-host=dh:10.0.2.2

as part of your docker run command or using

extra_hosts:
  - "dh:10.0.2.2"

in your docker-compose.yml file.

After this, connecting to mysql from a container with the client installed is as simple as (e.g.):

$ mysql -h dh -uroot -p1234

This solution does not require modifying the settings for your mariadb/mysql installation, even if it is bound to 127.0.0.0.

Tocopherol

Thanks to #30496405 and forums.docker.com/t/access-host-not-vm-from-inside-container/… for guiding me to this answer. – Tocopherol