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

[H. K. Ng]

Thanks Stuart for the explanation.

In the log entry, the student was switched from the load balancer to fsua1
and later to fsua2. Both times there is no login message. For this
particular student, the activities log indicates that the previous
successful login was 6 days ago on fsua1. Shouldn't fsua2 login the student
when his session is transferred to it? The emails that I get from students
is that they see a blank page. Is there anyway to prevent the display of a
blank page and show the roles page?

Thanks,
-hk




On Thu, Jan 22, 2015 at 6:51 PM, Stuart Raeburn <raeburn at msu.edu> wrote:

> 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
>
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