[LON-CAPA-admin] loncontrol not starting

Neubauer, Paul pneubauer at bsu.edu
Thu Dec 21 13:08:22 EST 2017

Thank you, Stuart. (Again!) I'm now back to "on". 

Hereafter, if I needed to rsync between different versions, I'd get everything from the old one and after running UPDATE, I'd probably want to:

rsync --dry-run -avz --exclude 'httpd/*' /home/ lon-capa01.aws.bsu.edu:/home

so as to exclude anything that might be problematic.

(I left the "--dry-run" in deliberately to prevent any simple cut-n-paste from causing anybody else to do something silly)


-----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: Thursday, December 21, 2017 12:17 PM
To: lon-capa-admin at mail.lon-capa.org
Subject: Re: [LON-CAPA-admin] loncontrol not starting


The error: "undefined symbol: Perl_Gthr_key_ptr" suggests an incompatibility between the compiled tth.so installed at /home/httpd/lib/perl/ and the perl version on your new LON-CAPA instance.

The tth module is one part of LON-CAPA for which the source is not distributed.  Instead compiled tth.so* files are included in the LON-CAPA tarball.

When you run ./UPDATE to install or update LON-CAPA, the script:

<some directory>/loncapa-2.11.2/modules/TexConvert/tthperl/commands

is run (where <some directory> is the location of the uncompressed LON-CAPA tarball from where ./UPDATE is being run).

That script will attempt to identify your Linux distro, architecture, and perl version, and copy the appropriate tth.so* from

<some directory>/loncapa-2.11.2/modules/TexConvert/tthperl/compiles



If you ran an rsync that copied tth.so* from an old instance of LON-CAPA (with a different perl version) to your new instance *after* running ./UPDATE that will have replaced the tth.so in /home/httpd/lib/perl/. (The same is true of capa.so).

If that is what happened, you can either run ./UPDATE again, or you could do:

cd <some directory>/loncapa-2.11.2/modules/TexConvert/tthperl/
bash commands

It is recommended to exclude tth.so and capa.so when running rsync to copy from one LON-CAPA instance to another, unless the two VMs are the same distro, architecture and perl version.

Stuart Raeburn
LON-CAPA Academic Consortium

> Hello All,
> I just built a new VM to take over as lon-capa.bsu.edu. I tested 
> everything on it and everything seemed to work. We just cut over the

> DNS to make lon-capa.bsu.edu point to the new VM. And I rebooted the

> system to give us a "clean" start with the new DNS.
> Now I can't connect to the system using
so I connected by ssh to the box and found that neither httpd nor loncontrol was running and when I try to start loncontrol, I get the following
> error:
> [root at lon-capa01 ~]# /etc/init.d/loncontrol start Opening firewall 
> access on port 5663.
> Port already open for 128 IP addresses Starting LON-CAPA Starting 
> LON-CAPA client and daemon processes (please be patient)
> /usr/bin/perl: symbol lookup error: /home/httpd/lib/perl//tth.so:  
> undefined symbol: Perl_Gthr_key_ptr
> What's going on here? Everything was working yesterday and this 
> morning, but now loncontrol won't start and we have a dead lon-capa.

> Any idea what tth.so is and why are there **two** slashes in the
> Thanks,
> Paul

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