We have connected Matterhorn to Moodle via LTI. Thereby, students can view the MH series list in Moodle and watch recordings.
We have seen that everytime a Moodle user gets authenticated in MH via LTI, there is a WARN message in the error log of the admin server saying
2015-03-10 05:49:13 WARN (RemoteUserAndOrganizationFilter:140) - Non-existing user 'lti:moodle-ng.uni-ulm.de:8746' specified in request header X-Opencast-Matterhorn-User
At the same time, on the engage node, there are loads of log messages saying something like
2015-04-01 10:11:03 WARN (RemoteBase:192) - Service at https://matterhorn.uni-ulm.de/series/f3cb8315-3763-4edf-828b-fe2e01fed26c.xml returned unexpected response code 403
Entwine has told us that these log messages are based on the way LTI authentication works in MH. They are not serious and don't affect our users. They might be fixed as soon as the LTI module will be improved.
However, we have seen that the engage node stops working sporadically every few days, it just does not answer any requests anymore and users can't view recordings anymore. This might be caused by the aforementioned problems which might produce some sort of ressource leak.
Restarting the engage node fixes the problem immediately.
Restarting the engage node with a cron job every night is a intermediate fix, but no real solution.