Forum Discussion

RahulG's avatar
RahulG
Icon for Altocumulus rankAltocumulus
Feb 15, 2021

Python for analyzing the Logs

We are having Tomcat memory issues on multiple F5 devices. We need to create a python script to analyze logs on multiple devices and find if there is a log "java.lang.OutOfMemoryError: " in /var/log/tomcat/catalina.out. Could someone please help me draft this script.

application delivery
devops
iControlREST
LTM
  • jaikumar_f5's avatar
    jaikumar_f5
    Icon for Noctilucent rankNoctilucent
    Feb 15, 2021

    Dont you have a centralized logging, like splunk, syslog servers. I'm sure there will be.

    Simply use splunk or your monitoring tool to search for the OOM log

  • Satoshi_Toyosa1's avatar
    Satoshi_Toyosa1
    Ret. Employee
    Feb 18, 2021

    If I do not want to use an external logging service, I am in a hurry, and my boxes have adequate power and bandwidth, I would use iControl REST POST /mgmt/tm/util/bash to call "cat <file> | grep keywords". Run this against all the boxes one by one.

    $ curl -sku $PASS https://$HOST/mgmt/tm/util/bash \
  -X POST -H "Content-type: application/json" \
 -d '{"command":"run", "utilCmdArgs": "-c \"cat /var/log/tomcat/catalina.out | grep \\\"Unknown version\\\"\""}' \
  | jq -r '.commandResult'
WARNING: Unknown version string [3.1]. Default version will be used.

    (I chose "Unknow version" for grepping as my log presently does not have OutOfMemoryError".)

    I chose jq for parsing. You can do the same using python, of course. Be careful with the double escaping for double-quotes. We can easily make mistakes (For the above call, I tried three times :-).

    For a sophisticated method for deploying logging facility, check F5 Telemetry Streaming.