[LON-CAPA-admin] LON-Balancer

[Stuart Raeburn]

Mark,

> Does one still need to make changes in the httpd loncapa config   
> file? Does one set it
> up totally through the web now?

The intention in 2.11 has been to support designation and  
configuration of "lonBalancer" instances (i.e., LON-CAPA load balancer  
servers) exclusively using the web, by accessing:

Main Menu -> Set domain configuration -> Display (Dedicated Load  
Balancer(s) checked) with the domain coordinator role active.

See the help file:  
https://loncapa.msu.edu/adm/help/Domain_Configuration_Load_Balancing.hlp

In the case where web configuration has yet to be used, but

lonBalancer yes

exists in an Apache config file, then the LON-CAPA instance will  
continue to operate as a load balancer, but without the various 2.11  
options for determining where particular groups of users are offloaded  
to.

However, in reviewing the 2.11.0 code I found one situation where  
"lonBalancer yes" in the Apache config was still consulted -- namely  
when an institutionally authenticated user first creates a new  
LON-CAPA account on a load balancer server.  I have just committed  
createaccount.pm rev. 1.69 to the LON-CAPA CVS repository.  This new  
version now fully eliminates the need for "lonBalancer yes" in an  
Apache config file.  createaccount.pm rev. 1.69 will be part of 2.11.1

At this point you have two options with 2.11.0:

(a) Use the web GUI to configure load balancing, and also include  
"lonBalancer yes" in an Apache config file to support the one  
situation with self-creation of accounts discussed above.

or

(b) Use the web GUI to configure load balancing, and replace  
createaccount.pm rev 1.68 (included in 2.11.0) with rev. 1.69 using:

wget -O /home/httpd/lib/perl/Apache/createaccount.pm  
'http://source.loncapa.org/cgi-bin/cvsweb.cgi/~checkout~/loncom/interface/createaccount.pm?rev=1.69;content-type=text/plain'

/etc/init.d/httpd reload

(Note: by doing this, you will cause the nightly module version check  
to send an e-mail because of the discrepancy between the expected  
(1.68) and installed (1.69) versions).


Stuart Raeburn
LON-CAPA Academic Consortium

Quoting "Lucas, Mark" <lucasm at ohio.edu>:

> What is the accepted practice for setting up a Balancing machine nowadays?
> I moved my balancer to a different machine last Fall when I bumped   
> up to 2.11.0
> and it did not seem to be working right. It seemed to be keeping   
> some sessions on the
> balancer itself and did not seem to be transferring sessions to the   
> main access servers
> as consistently as it should. I pointed to one of the standard   
> access servers and left it at that.
>
> I know that there is now extra configuration information in the   
> domain coordinator's online
> settings for the domain. What is the accepted way to set up a brand   
> new LON Balancer?
> Does one still need to make changes in the httpd loncapa config   
> file? Does one set it
> up totally through the web now?
>
> Thanks!
> Mark
>
> --
> Mark Lucas 								email: lucasm at ohiou.edu
> 252D Clippinger Lab						phone: (740)597-2984
> Department of Physics and Astronomy		fax: (740)593-0433
> Ohio University
> Athens, OH 45701
>
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