Djatoka hanging on restart

[Aaron Krebeck]

Hello all.  About half the time, after restarting our Islandora servers, all book objects are not viewable. It seems that the Djatoka viewer hangs up and while the book object loads, the actual IA Book viewer pages appear with a broken link. Restarting Tomcat resolves the issue every time, but I'd like to get to the bottom of this. Has anyone else had a similar problem. It seems like it could be an order of operations issue. Perhaps Java/Djatoka needs to wait for something else to come up before starting.

[lu...@discoverygarden.ca]

Hi Aaron,

I have noticed this behaviour many times. If Apache is active and something tries to hit Djatoka before Tomcat is ready it won't work any more till you restart tomcat again. If you make sure tomcat is up and active before starting Apache this shouldn't happen. What is odd is that it only seems to happen if something tries to hit Djatoka before it is ready. Not exactly sure what causes this. 

Luke

[Aaron Krebeck]

Thanks for the information Luke.  We have added some wait time to the apache2 start.  I'll do a restart this weekend and let you know how things work out.

[Luke Taylor]

You also need to make sure that Apache is off before you restart the backend. 

Luke Taylor
DevOps Team Lead
discoverygarden inc.

155 Queen St. Suite 101
Charlottetown, PE C1A 4B4 
902.367.3851 discoverygarden.ca
lu...@discoverygarden.ca

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[Brad Spry]

You can turn on Java's error logging in your JAVA_OPTS:
-XX:ErrorFile=/var/log/islandora/java/java_error%p.log

Maybe a tidbit of actionable information will be revealed...


FYI: I start Tomcat after Apache, without issue.  Additionally, I restart Tomcat nightly, without shutting down Apache at all, without issue.


Brad

[lu...@discoverygarden.ca]

Thanks for the tip Brad. I tried enabling the ErrorFile unfortunately it doesn't seem to log anything. It is a really odd problem. Generally speaking I can restart Tomcat/Apache etc and Djatoka works fine. It just seems to break if someone happens to try to hit the Djatoka resolver in a certain way when Tomcat is turned off.  

[Brad Spry]

ps -aux |grep java

If you don't see "-XX:ErrorFile" contained in your java command, then the variable isn't set properly...

I set mine at the bottom of:
/usr/local/fedora/tomcat/bin/startup.sh

<B

[lu...@discoverygarden.ca]

Made sure it is showing up but still doesn't seem to log anything. Made sure tomcat has r/w permissions to the log folder. -XX:ErrorFile=/var/log/islandora/java_error%p.log does yours have quotes or anything?

[Brad Spry]

If it's not logging anything, that's a good sign...   I believe you're doing everything right.

At least now you have another very low level log, that could potentially contain some tidbit of information to debug with.


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