[LON-CAPA-admin] Hostname change

Lucas, Richard clucas at purdue.edu
Mon Nov 16 14:13:58 EST 2015


Stuart,

Thanks for the quick answer, this seems pretty straight forward. We likely will not be doing anything until January at the earliest, but I wanted to see what it would take. I will let you know before we do it.

Thanks,
Richard

-----Original Message-----
From: lon-capa-admin-bounces at mail.lon-capa.org [mailto:lon-capa-admin-bounces at mail.lon-capa.org] On Behalf Of Stuart Raeburn
Sent: Monday, November 16, 2015 1:30 PM
To: lon-capa-admin at mail.lon-capa.org
Subject: Re: [LON-CAPA-admin] Hostname change

Richard,

You can change the hostname of a library server, but you should avoid changing  the lonHostID.  So, for your library server in the purdue domain, the lonHostID should remain as purduel1.

Let's say you decide to assign a hostname of loncapa01.purdue.edu to the new library server.

You will need to modify /home/httpd/lonTabs/hosts.tab to replace

purduel1:purdue:library:loncapa.purdue.edu:https:purdue.edu

with

purduel1:purdue:library:loncapa01.purdue.edu:https:purdue.edu

(If you like you can also make the same change to /home/httpd/lonTabs/dns_hosts.tab on all nodes in your domain, but that file is only consulted if none of the LON-CAPA "DNS" servers at MSU, UIUC or SFU are contactable).

Depending on when you make the change to hosts.tab and restart the LON-CAPA daemons and the web server, there could be up to 24 hours when your library server will not be able to connect to other servers in the network.

You can minimize the length of time without connectivity by switching the library server's hostname, and restarting the daemons, shortly before 5.10 am EST.  Other servers in the network will run /home/httpd/perl/loncron as user www at 5.10 am local time (and the majority of LON-CAPA servers are in US time zones) to update their cluster information.

If you let me know the evening before you make the change then I will update the "DNS" servers at MSU, UIUC and SFU with an updated dns_hosts.tab, so that when loncron next runs on each server in the network, the hostname <=> lonHostID mapping for your library server will reflect the new configuration.

At that time I would also include the new record for the load balancer, e.g., purduea6:purdue:access:loncapa.purdue.edu:https:purdue.edu in the updated dns_hosts.tab files on the msu, uiuc and sfu library servers.


Stuart Raeburn
LON-CAPA Academic Consortium


Quoting "Lucas, Richard" <clucas at purdue.edu>:

> We currently use our library server (loncapa.purdue.edu) as a load   
> balancer. We would like to add another node to do load balancing and  
> move our library server to more of a backend role. However, we would  
> like to retain the loncapa.purdue.edu for the load balancer.
> In  order to accomplish this I would like to change the hostname of 
> our  library server. What is needed to accomplish this without messing 
> up  the connections to the LON-CAPA network?
>
> Thanks,
> Richard

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