Aws Rds - Mysql Block host due to many connections

Question

Recently I have migrated the wordpress database to AWS RDS Large Instance (MySQL 5.6.12). After that occasionally Mysql locked my ec2 instance Ip with below error message.

"blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'".

Anyone knows the reason & permanent solution to resolve this problem?

Cloudwatch shows maximum CPU Utilization upto 70%.

Solution

In short. You need to give us more information on your application, the problem, logs, etc

Have you configured your MySQL Instance?

By default, mysqld blocks a host after 10 connection errors. http://dev.mysql.com/doc/refman/5.0/en/blocked-host.html

While this might be fine normally, your setup might call for different settings.

Of course you should check your logs to see why you are receive the connection errors in the first place. It could be a bad script, or an application related bug.

It's unlikely to be a firewall issue if it was working and all of a sudden isn't, but it's worth making sure the firewall is still set correctly. It's also worth checking to see if you can connect yourself, not look at logs.

Comments

[Tom O'Connor]

Did you set up proper security on the RDS instance?

[user103373]

yes, I have allowed the only Ip of my ec2 instance in RDS security group

[Drew Khoury]

Have you looked into it at all? stackoverflow.com/questions/8722565/…