[LON-CAPA-admin] Adding Access servers

[Todd Ruskell]

Hi all,

We're about to finally incorporate two access servers, and simultaneously 
update our library server to 1.3.x,  and I have a couple of config questions 
before we jump right in.  First, what I believe I understand I need to do:

1) When asked, select "Access Server" when I install lon-capa, but choose the 
same domain
2) Add the 2 access servers to the hosts.tab on both access servers and the 
library server.
3) restart loncontrol and httpd on all machines
4) ask that the access servers eventually get added to the hosts.tab which 
gets distributed in the tarball.

Now the questions to which I haven't been able to dig up answers in the 
archives or faq-o-matic.

1) If I have a course that uses resources from another domain, and I log into 
the access server, will I be able to use those resources if the access server 
hasn't propagated to the other domain's hosts.tab?

2) I will now have 3 servers, call them library, access1 and access2.  In the 
base installed mode, I'm guessing that I need to tell students to change 
their habits and connect directly into access1 or access2, rather than 
library.  Is that correct?  In this situation, I suppose it is also possible 
that everyone logs into access1, while access2 sits completely idle until the 
load limit on access1 is reached.  Is this true?  If so, this strikes me as 
inefficient, which leads to:

3) In an ideal situation, I'd like to tell students to just go to, e.g., 
loncapa.mines.edu, and have lon-capa or some other mechanism figure out how 
to truly load-balance between my two access servers, but keep direct access 
to the library essentially for faculty only.  I'm presuming this is possible.  
What tools have been used, or are recommended to implement this?  I seem to 
recall Mark saying something about DNS load balancing a while back, but it's 
not clear to me if that's automagically part of lon-capa, or if I need extra 
tools.

Thanks for your help,

Todd