<div dir="ltr">In my experience you want to add a nagios user in your mysql db. Grant it priv types that your check will use like "SELECT, PROCESS, REPLICATION CLIENT" ? You might want to tighten the grant down to a specific ip only or range of your nagios server as well. <div> </div><div> </div></div><div class="gmail_extra"> <div class="gmail_quote">On Wed, Mar 1, 2017 at 11:36 AM, John Fowler <<a href="mailto:john.fowler@connection.com" target="_blank">john.fowler@connection.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div lang="EN-US" link="#0563C1" vlink="#954F72"> <div class="m_5093268659296846580WordSection1"> Hello, I have a question regarding the check_mysql plug-in. I’m not a Linux admin and have had little experience with Nagios. I am a MySQL DBA and have noticed access denied messages in the MySQL error log on servers where we are using the check_mysql Nagios plug-in. The check is scheduled to happen every 5 minutes and that is the frequency I'm seeing these authentication failure messages in the MySQL error log. The command that's getting issued every 5 minutes is as follows: $USER1$/check_mysql -H $HOSTADDRESS$ -n The user associated with the message is not root, but rather the user account associated with our Linux admin who set up the Nagios service check. I'd like to prevent these messages from being constantly written to the error log and creating a lot of "white noise". I understand the "-n" switch in the command above is to ignore authentication failure and just check MySQL connectivity. But the authentication failures are causing repeating access denied messages to get written to the MySQL error log. What is the best practice for using the check_mysql plug-in? Do we have to create a user account for the Nagios account performing the check? Is there any other way to check MySQL connectivity without a MySQL account? Thanks, John </div> </div> </blockquote></div> </div>