mysql-proxy-discuss team mailing list archive

[Jan Kneschke <jan@xxxxxxxxxxx>]

Samit Pal wrote:
> Hi Folks,
> 
> I plan to use the following mysql architecture. We will have multiple
> mysql servers on different ports on the same machine. Each db server
> process will run as a different user. I want to use mysql proxy and
> run it on port 3306 (on the same machine may be to start with), so
> essentially users connect to the mysql proxy which should switch the
> connection to the appropriate db server possibly based on the username
> supplied. I am not looking for load balancing, just pure switching. Is
> this possible with mysql proxy?

Nope. It is not and won't ever be possible in a transparent way.

The problem is the way the auth-protocol works:
1) client connects proxy,
   proxy connects to a server and get a "challenge",
   sends it back to client
2) clients send username and the scrambled password
   as response to the challenge to the proxy ... to the server

At the time you get access to the username, you already had to select a
mysql-server to connect to.

The only way to make it work is:
1) client connects to proxy, proxy sends back the challenge
2) client sends username + response to proxy
   proxy verifies data against a local auth-storage
   proxy connects to server, gets a new challenge
   proxy sends client's username + scramble password

The problem is: the local auth-storage has to have the same information
as the mysql-servers mysql.user table. We need that hashed password or
cleartext-password, any of them is fine. None of them is on the network.

We don't support that yet, but that's the only way to do it.

It is easy if you do something else instead:
* give each user its own IP address
* put all the IPs as virtual interface on the proxy box
* let the proxy check the proxy.connection.client.dst.address what IP
the client connected and pick the right backend
* that works in 0.7.x

> Thanx
> Samit

cheers,
  Jan
-- 
 jan: "Gee, Brain^WEric, what'd you wanna do tonight?"
eric: Same thing we do everynight: Take over the HelloWorld!