MySQL Bugs: #37829: MEM doesn't report a problem appropriately when the user and password are wrong

Bug #37829	MEM doesn't report a problem appropriately when the user and password are wrong
Submitted:	3 Jul 2008 6:51	Modified:	12 Oct 2009 22:22
Reporter:	Akiko Yonemura	Email Updates:
Status:	Duplicate	Impact on me:	None
Category:	MySQL Enterprise Monitor: Advisors/Rules	Severity:	S3 (Non-critical)
Version:	MEM 1.3.2	OS:	Any
Assigned to:	Jan Kneschke	CPU Architecture:	Any
Tags:	advisor, mem

Description:
MEM Advisor explains about "Agent Not Communicating With Database Server" like below.

Investigate why the agent cannot communicate with the local MySQL database server. Ensure that the agent has the correct login credentials (login and password). If necessary, change the login credentials in the [mysqld] section of the agent's INI file or create an account with the specified login credentials in the MySQL server. The last error message reported by the server is: %server.last_error%.

However when I change the login id and passwod in the [mysqld] of mysql-service-agent.ini with the incorrect ones and restart the agent with "enterprise/agent/etc/init.d/mysql-service-agent start" command, "Agent Not Communicating With Database Server" desn't show up in the Event screen. 

In stead of it, the error like below shows up in mysql-service-agent.log.

2008-07-02 21:11:10: (critical) connecting to mysql-server 127.0.0.1 failed: Access denied for user 'xxx'@'localhost' (using password: YES) (1045)

How to repeat:
1. Chenge the login id and passwod in the [mysqld] of mysql-service-agent.ini with the incorrect ones.
2. Restart the agent.

Suggested fix:
Allow MEM to handle ERROR 1045, and  generate "Agent Not Communicating With Database Server" when getting 1045.

closing this as a bug - may be considered a suggestion

I try to reproduce the same behavior under MEM 2.0.

Once an agent can login to mysql server to be audited, Communication error could cause this error,

'MySQL Server Not Reachable'.

But agent-instance.ini with wrong login information(e.g. wrong username or password), agent can activate, but dashboard don't report 'MySQL Server Not Reachable' nor 'Agent Not Communicating With Database Server'.

Each events have a description like this,
"Ensure that the agent has the correct login credentials (login and password). "

This description mislead a user to occur events if a user use a wrong user or password. But at that time no event reported to Dashboard.

And I don't understand a difference between 'MySQL Server Not Reachable' and 'Agent Not Communicating With Database Server'. I always see 'MySQL Server Not Reachable', but I have never seen 'Agent Not Communicating With Database Server'. What condition can that error occur?

Gary Whizin writes: 
We're trying to freeze 2.1, so this is a good candidate for the first 2.1 maint release (can start on it when all 2.1 "by GA" tasks are done).

The Agent needs to login to the mysqld being monitored in order to correctly identify itself to the Dashboard (i.e. to get the UUID of the server from the mysql.inventory table).  So you won't see this rule fire if you change the password and restart the agent.

You will see this rule fire if you change the password of the MySQL user account that the agent is using *while the agent is running*.  In other words:

1) Start an agent and see it in the Dashboard.
2) Login to the MySQL server being monitored by the agent and change
   the password for the agent account:
     SET PASSWORD FOR 'agent'@'localhost' = PASSWORD('newpass');
3) Kill the agent's current login session so it must login again and
   re-authenticate itself
4) Wait a minute or two and you'll see the rule fire and show an
   event.

Andy Bang writes: 
This has been split into the following:

* EM-3645/Bug #48010 - Service Manager should allow Agent to report problems when mysqld UUID not known
* EM-3646/Bug #48011 - Agent should report problems to Service Manager even when mysqld UUID not known
* EM-3647/Bug #48012 - Update "Agent Not Communicating..." rule with new data collection item
* EM-300/Bug #41630 - A more intelligent agent installer

So we are closing this one now and tracking the others.