MySQL Bugs: #22124: Instance Manager: monitors server instances using invalid username

Bug #22124	Instance Manager: monitors server instances using invalid username
Submitted:	8 Sep 2006 17:21	Modified:	5 Oct 2007 15:18
Reporter:	Paul DuBois	Email Updates:
Status:	Unsupported	Impact on me:	None
Category:	Instance Manager	Severity:	S3 (Non-critical)
Version:	all	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Instance Manager attempts to monitor guarded
instances by connecting with a username of
MySQL_Instance_Manager. But MySQL usernames
have a maximum length of 16 characters. This is a
problem because:

- It is not possible for users to create an acccount with
that username, should they wish connection attempts by
IM to succeed.

- If the monitored server does not support that account
(which is the usual case), messages appear in the general
query log that show a username of MySQL_Instance_M.

- In the documentation, we must refer both to the actual
username used by IM, and to the error messages in the
query log. This means we have to refer both to
MySQL_Instance_Manager and MySQL_Instance_M, which
is confusing for users and looks silly in the documentation.
It also means that for each reference to the username,
documenters must double-check the context in which
the reference occurs to make sure whether the full name
or the truncated name is correct in that context.

How to repeat:
See above.

Suggested fix:
Please have Instance Manager actually use a username
of MySQL_Instance_M, so that the name is a legal length
and does not produce inconsistencies between the name
that is sent to the server and the name that appears in
the query log.

Alternatively, please choose some other username that
is within the 16-character limit.

Thanks.

Thank you for a problem report.

Actually, this issue has been already risen in BUG#17963
(instance manager changes connection statistics).

> It is not possible for users to create an acccount with
> that username, should they wish connection attempts by
> IM to succeed

This behaviour has been implemented intentionally. IM uses
"private" account and ensures that no one else can use it.
Otherwise, it could be a security breach.

Okay, I grant that the behavior is intentional
and that the account used is intended to be "private".
But could that same intent be satisfied with a
username that is within the 16-character limit
and would not introduce a mismatch between the
username that IM sends to the server and that
appears log message that logs the failed
connection attempt? This is actually my main
concern, because the difference is confusing and
also make the manual look strange when we end up
referring to both names in close proximity...

Re-opened after discussion with Petr.

It seems, there is no reason to have exact
"MySQL_Instance_Manager" user name.
So, we can change the name to something like
"MySQL_IM".