Bug 24536

Summary:	Enhancement to nanny
Product:	[Retired] Red Hat High Availability Server	Reporter:	Tinus Strauss <tinus>
Component:	piranha	Assignee:	Phil Copeland <copeland>
Status:	CLOSED NOTABUG	QA Contact:	Phil Copeland <copeland>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	1.0	Keywords:	FutureFeature
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2001-05-07 20:22:42 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Red Hat Bugzilla 2001-01-22 08:44:52 UTC

Hi,

I have a request for an enhancement to nanny. 
I want to be able to specify a number, say n, so that a real server is made unavailable 
only after it missed n polls instead of just one.

Thanks
Tinus

Comment 1 Red Hat Bugzilla 2001-05-07 20:22:34 UTC

Are you asking this for FOS, LVS, or both? And why isn't a single failure
acceptable? It would be easy to use this feature as a method of hiding a
different problem.

Comment 2 Red Hat Bugzilla 2001-05-17 09:07:20 UTC

Hi,

I was using LVS. I had real servers that will accept connection on the port of the 
service even though they cannot really service the requests. The send/expect string 
functionality of nanny was not of use in this situation.  For this reason I set the re-entry 
time to something like 20 minutes.
BUT. . .
I had a problem (at the real servers) where nanny sometimes declared a real server 
dead when it, in fact, was not.  And it waited 20 minutes to be made available again.
I thought that the probability of missing, say, two consecutive polls to be sufficiently low
to solve my problem.  Eventually I "managed" the problem by running an additional service 
on the real servers to test their states.  It is not elegent but is is sufficient.  When the 
servers start there is a delay after the actual service starts and before the additional service 
starts.  The re-entry time is thus a couple of seconds again.

I had some other issues with this setup for which I needed the fwmark functionality, which 
piranha did not have support for at that time.  I decided to use heartbeat plus ldirectord. . .

So basically I had some issues and I thought this "enhancement" might help.  
Currently I'm not using piranha, as mentioned above.

Cheers
Tinus

Comment 3 Red Hat Bugzilla 2001-05-18 17:00:48 UTC

>I was using LVS. I had real servers that will accept connection on the port of
>the service even though they cannot really service the requests.

Isn't this the same as saying the service was overloaded and declaring it dead
for further connection attempts would be a good thing? Why wouldn't the correct
"fix" be to added additional servers to respond to the load?

> The send/expect string 
> functionality of nanny was not of use in this situation.  For this reason I
>set the re-entry 
> time to something like 20 minutes.

Why not just not use a send/expect string? If successful connections was the
best test of validation, then you could have limited nanny to just doing that.

>Eventually I "managed" the problem by running an additional service 
>on the real servers to test their states. 

This actually sounds like a better solution than -- you are solving a response
problem by distributing the load.