[LON-CAPA-admin] Reloading spare.tab

[Stuart Raeburn]

Mark,

Yes it does.

spare.tab is read within the BEGIN block in lonnet.pm which results in  
population of the %spareid hash (a global).

lonnet::spareserver() is the routine which makes use of %spareid to  
determine which servers to try.  It tries any servers designated as  
"primary" first, and identifies the one with the lowest load.  This is  
the server it will return unless the lowest load is 100 or more, in  
which case it will try the servers designated as "default", and  
identify the server with the lowest load from that group.  That is the  
server it will return unless the lowest load in the "default" group is  
higher than the lowest load in the "primary" group.

lonnet:;spareserver() is called by lonlogin.pm -- to allow an  
overloaded server to send users hoping to log-in to LON-CAPA via that  
particular server to another  machine to host the user sessions), and  
also by switchserver.pm -- to load balance after successful  
authentication when:

PerlSetVar lonBalancer yes

appears in the Apache config files for the server.

As these operations rely on the contents of the global %spareid hash  
for the particular Apache child, /etc/init.d/httpd reload is  
sufficient as that reloads all of the Apache children.

Stuart Raeburn
MSU LON-CAPA group

Quoting Mark Lucas <lucasm at ohio.edu>:

> Stuart,
>
> Does that really reload the spare table into the appropriate places? If
> so, great!
>
> Mark
> On Thu, 2008-09-11 at 09:34 -0400, Stuart Raeburn wrote:
>> Mark,
>>
>> /etc/init.d/httpd reload is what I use.
>>
>> Stuart Raeburn
>> MSU LON-CAPA group
>>
>> Quoting Mark Lucas <lucasm at ohio.edu>:
>>
>> > Hi,
>> >
>> > I'm playing around with my spare.tab for lonbalancer.
>> >
>> > What's the least intrusive way of handling the reload?
>> >
>> > Will /sbin/service loncontrol reload do this without interrupting
>> > services?
>> >
>> > 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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>> >
>>
>>
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