Home/ Questions/Q 9214611
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-18T02:00:29+00:00

For our application, setup on the Amazon EC2 instances, we are using MySQL databases,

  • 0

For our application, setup on the Amazon EC2 instances, we are using MySQL databases, installed on 2 EC2 instances, in master-master replication mode. To load balance these DB Servers I am using an HAProxy deployed on another EC2 instance with configuration

listen  mysql <public dns of haproxy>:<port>
mode tcp
balance roundrobin
server mysql-db-s1 <elastic ip of db server1>:<port> maxconn 2000
server mysql-db-s2 <elastic ip of db server2>:<port> maxconn 2000

All three instances are assigned elastic ip’s and I use the public dns of haproxy to connect from my application. But at times I get the error

 `com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: C
  ommunications link failure The last packet successfully received from the server was  58,085 milliseconds ago.  
  The last packet sent successfully to the server was 0 milliseconds ago.`

Has this anything to do with the configuration I have given here? Is it better to use the elastic ip’s instead of Public DNS ?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    This was not essentially an HAProxy issue, as I got the same error after I connected directly to one of the databases. Tuned the database a little and fixed some code in my application, and now I am not getting this atleast for the past 12 hours. Thanks for the suggestions. I would be moving one of the DB to another availability zone.

    • 0