Core Engine (Galactica) threads monitoring
In some cases, you may need more information about the behavior of the Indexima Core Engine (Galactica).
In order to do this you can retrieve a "thread dump" of the Galactica instance.
You can retrieve a thread dump like this:
- Log in on a master with the same user you used to run Indexima
- Use the jps tool to determine the pid of the Galactica instance (NodeServer)
It will return the following list:
9536 NodeServer 17457 GaYarnLauncher 6984 Jps 18392 NodeServer 10381 Visualdoop 8911 GaYarnLauncher
If you have many NodeServer instances, you can search for the one you want to investigate by doing a pstree and looking for the applicationId.
- When you have the pid of the correct NodeServer :
/usr/jdk64/jdk1.8.0_112/bin/jstack (PID of NodeServer)
- You can now redirect the output into a file.
How to get a "thread dump" at regular intervals
On Hortonworks :
- Create a directory.
- Launch the thread dump every 300 seconds, 10 times.
for I in `seq 0 10` ; do /usr/jdk64/jdk1.8.0_112/bin/jstack (PID of NodeServer) > threaddump.$(date +"%Y-%m-%d_%H:%M:%S").txt ; sleep 300 ; done
This command uses a lot of processing power so be careful not to execute this command too quickly.