[LON-CAPA-admin] Switch server but no role

[Stuart Raeburn]

Hi,

> Question is why there is no role for the student? Is it a timeout issue?

That can happen in the following scenario:

1. I open a new tab in my web browser and log-in to LON-CAPA via a  
load balancer server.

2. I select a role from the roles screen displayed after being  
switched to the session-hosting server.

3. I close that browser tab, but don't quit my browser, and don't  
explicitly log-out of LON-CAPA using the "Logout" link at top right.

4. Some time later I open another tab in the same browser and log-in  
via the load balancer. If my session is switched to the same server as  
used in the earlier session then all I would see in my activity.log  
file would be the one line:

time <load-balancer lonhostID> Switch Server to <host> with role  <ip addr>

i.e., no "Log-in" entry and no "Role" entry.

The activity.log entries you reported originate from  
/home/httpd/lib/perl/Apache/switchserver.pm on the loadbalancer server  
(fsua0).

If you look in the Apache web server access log file on the intended  
session-hosting server (fsua1) you should find a number of entries of  
the form:

<ip add> /adm/login?domain=<domain>&username=<username>& ...

where <ip add> is the user's IP address, <domain> is the user's  
domain, <username> is the user's username, and ... is the rest of the  
query string.

Typically, no role is specified when a user logs-in to a load  
balancer.  Instead the session-hosting server will send the roles  
screen to the user's browser (after migration) for the user to select  
a role.

In that instance the expected sequence of entries logged in the user's  
activity.log file is:

(a) time <load-balancer lonhostID> Switch Server to <host> with role   
<ip addr>
(b) time <session lonhostID>       Login <ip addr>
(c) time <session lonhostID>       Role <role selected>

where (a) is a log entry submitted by the load-balancer; (b) and (c)  
are entries submitted by the session hosting server -- (b) when  
session migration is successful; (c) when the user selects a role.


Stuart Raeburn
LON-CAPA Academic Consortium


Quoting "H. K. Ng" <hkng at fsu.edu>:

> Hi,
>
> Occasionally, I have students who log in to the lonbalancer and get
> switched to one of the access servers but no role shows up. The activity
> log shows something like
>
> 1421954366:fsua0:Switch Server to fsua1 with role  <ip add>
> 1421954585:fsua0:Switch Server to fsua1 with role  <ip add>
> 1421954681:fsua0:Switch Server to fsua1 with role  <ip add>
> 1421954821:fsua0:Switch Server to fsua1 with role  <ip add>
> 1421954852:fsua0:Switch Server to fsua1 with role  <ip add>
> 1421954881:fsua0:Switch Server to fsua1 with role  <ip add>
> 1421954991:fsua0:Switch Server to fsua1 with role  <ip add>
> 1421955126:fsua0:Switch Server to fsua2 with role  <ip add>
> 1421955167:fsua0:Switch Server to fsua2 with role  <ip add>
> 1421955293:fsua0:Switch Server to fsua1 with role  <ip add>
>
> Seems that if it is successful, it shows a login to the access server and
> then  the role shows up, e.g.,
>
> 1421955305:fsua1:Login <ip add>
> 1421955310:fsua0:Switch Server to fsua1 with role  <ip add>
> 1421955311:fsua1:Login <ip add>
> 1421955324:fsua1:Role st./fsu/<course id>/1
>
> Question is why there is no role for the student? Is it a timeout issue?
>
> Thanks,
> -hk