I have have set up MySQL multi-master replication with HAProxy as a load balancer following Alex Williams' tutorial found here; http://www.alexwilliams.ca/blog/2009/08/10/using-haproxy-for-mysql-failover-and-redundancy/
I am using a status checker found here; http://sysbible.org/2008/12/04/having-haproxy-check-mysql-status-through-a-xinetd-script/
as well as a replication checker found here; http://forge.mysql.com/tools/tool.php?id=6
The Mysql status checker works fine when I have the following line in my HAProxy config file:
server db02 192.168.15.119:3306 check port 9200 inter 1s weight 1 rise 1 fall 1
But when I try to test the check replication script with this line:
server db02 192.168.15.119:3306 check port 9201 inter 1s weight 1 rise 1 fall 1
and try to connect through the proxy I get a failure:
ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 0
When I telnet from the HAProxy machine to that port it works fine:
# telnet 192.168.15.119 9201 Trying 192.168.15.119... Connected to 192.168.15.119. Escape character is '^]'. Replication slave is running Connection closed by foreign host.
Is there any reason that that would not work while I can still check it through telnet? Is this a limitation of HAProxy? I would assume not as it seems that this is what others have used for their setups. Is it a configuration or permissions issue? I am confused as to how one of them would work and let me connect fine, but the other will not.