[LON-CAPA-users] Unresponsive lon-capa

[Stuart Raeburn]

Hi,

> So what's plan B?  There must be another way to get the
> information on the back end if I have a healthy ssh login.

If you install lynx (the RPM is included in the standard RHEL 4 distro).

On RHEL4:

up2date -i lynx

then you can use:

/usr/sbin/apachectl fullstatus

from the command line in an ssh session on <yourserver> to retrieve  
the same information as a web browser will display with a request for:

http://<yourserver>/server-status/

> Also, when attempting access to Set Domain Configuration,
> while at this time the apache service is responding
> normally, I saw an error just now:
>
> Something somewhere went wrong... etc. - the report form.
>
> The error was:
>
> Internal info:
>
> ERROR:
> Undefined subroutine &Apache::domainprefs::handler called.

This error is specific to Apache 1.3 (only currently used for LON-CAPA  
with Redhat Enterprise 4).  The solution is to include the line:

use Apache::domainprefs();

in /etc/httpd/conf/startup.pl

A revised version of the startup.pl file (for LON-CAPA 2.9) includes  
this change. So if you replace rev. 1.34 of startup.pl with rev  
1.34.10.1, and reload httpd you will eliminate the ISE seen on RHEL4  
when the DC displays the Domain Configuration page.

All on one line:

wget -O /etc/httpd/conf/startup.pl  
'http://source.loncapa.org/cgi-bin/cvsweb.cgi/~checkout~/loncom/startup.pl?rev=1.34.10.1;content-type=text/plain'

Then:

/etc/init.d/httpd reload

You may also want to replace domainprefs.pm included in 2.9.1 with an  
updated version, which includes three changes to suppress warnings  
displayed when starting Apache 1.3.

All on one line (for LON-CAPA 2.9.1):

wget -O /home/httpd/lib/perl/Apache/domainprefs.pm  
'http://source.loncapa.org/cgi-bin/cvsweb.cgi/~checkout~/loncom/interface/domainprefs.pm?rev=1.102.2.16;content-type=text/plain'

>
> I guess I'm missing some perl modules or mine are out of date.
>

No you are not missing anything.  This issue seems to be a peculiarity  
of LON-CAPA running on Apache 1.3.

If you prefer not to modify startup.pl on your own library server you  
could  display the Domain Configuration page without error by logging  
into a different server in the network (i.e., one not running RHEL4),  
e.g.,

http://educog.com/

using your username and password for your LON-CAPA account (with the  
DC role) and changing the default domain on the educog server from  
"author" to your own domain name, when logging-in.

Stuart Raeburn
MSU LON-CAPA group

Quoting D G Teed <donald.teed@gmail.com>:

> On Mon, Feb 7, 2011 at 12:00 PM, Stuart Raeburn <raeburn@msu.edu> wrote:
>>
>> Hi,
>>
>> Gerd mentioned the Apache server-status page:   
>> "http://(yourserver)/server-status/" and indicated he would send   
>> the password to access this page.
>>
>> Starting with LON-CAPA 2.8.0 access to this page (and some other   
>> status pages) was switched from using htpasswd-based authentication  
>>  and authorization, to using access control via LON-CAPA (and   
>> configured for a domain by the Domain Coordinator).
>>
>> When logged into LON-CAPA, Domain Coordinators can view this page via:
>> Main Menu -> Status of domain servers -> Apache Server Status
>>
>> A Domain Coordinator can also configure access to this page via:
>> Main Menu -> Set domain configuration -> Display [Access to server   
>> status pages (checked)]
>>
>> One of the access modes supported is IP-based, which permits   
>> display of server-status from a specified machine without the need   
>> for log-in to LON-CAPA.  This can be useful for remote monitoring.
>>
>>> Yes, http://(yourserver)/server-status/
>>>
>>> - that will show you what the server is busy doing and you can   
>>> find  the problem that's the problem. I'll send you passwords in a  
>>>  minute.
>>>
>>
>> There can be a difficulty here in that once Apache has reached its   
>> maximum clients limit, and all clients are busy, possibly serving   
>> looped processes, it is difficult to get a free Apache client to   
>> display the server-status page.
>>
>
> A non-responding apache service has been the consistent
> problem.  Last year I saw cases where the I/O was
> grinding the server to death and it wasn't responsive
> in any way.  But in the last case, it only impacted the
> apache service, and the page would not display for
> login - nothing at all, but browser timeouts trying
> to reach it.  Even the logs were silent when I tried to
> get the login screen.
>
> So what's plan B?  There must be another way to get the
> information on the back end if I have a healthy ssh login.
>
> Also, when attempting access to Set Domain Configuration,
> while at this time the apache service is responding
> normally, I saw an error just now:
>
> Something somewhere went wrong... etc. - the report form.
>
> The error was:
>
> Internal info:
>
> ERROR:
> Undefined subroutine &Apache::domainprefs::handler called.
>
> REQUEST_URI:
> /adm/domainprefs
> SCRIPT:
> /home/httpd/html/adm/domainprefs
> SCRIPT:
> /adm/domainprefs
>
> In the error.log:
>
> Undefined subroutine &Apache::domainprefs::handler called.\n
>
> I guess I'm missing some perl modules or mine are out of date.
>
> I'm able to get to the server-status page at this moment using the
> "Status of domain servers" link.  I'll try monitoring this in case it
> is useful.
>
> --Donald Teed