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7 posts from October 2009


Help Wanted: Generating Remote Thread Dumps for Large Numbers of Servers

A recent commenter on this site posted a request for assistance on generating thread dumps remotely, quickly, across a large number (30+) of servers, whenever an incident occurs.  I thought it would be a good idea to solicit ideas from anyone reading this site for ideas on how you might be doing it.  

When a failure occurs within their web application, he must remotely generate thread dumps across 34 load-balanced jboss systems and restore service as quickly as possible.  Since I've been experimenting a lot with Jmx4Perl and we are talking specifically about JBoss servers, scripting something in Jmx4Perl that would iterate through a list of servers would certainly be worth a try since Jmx4Perl has built-in methods that would help. Is anyone out there doing something similar today?  JMX-Console is too slow for his purposes and depending upon the failure, both jmx-console and jmx4perl might not be all that usable, (if for example, the http connector is dead).

I would love to hear what other people are doing managing large clusters of JBoss systems, especially in the area of remotely generating thread dumps.  Please brag about it in the comments! :)  Let's assume, for the solution's sake, that we do not know 'why' he has to remotely generate thread dumps across this many systems.


Apache HTTP Server v2.2.14 Released

The Apache HTTP Server project has released version 2.2.14.  The release fixes three security vulnerabilities and 11 bugs and renders thousands of web sites out of PCI Compliance.  (ok, ok, technically you are not out of compliance instantaneously)

Apache on Solaris and mod_proxy_ftp users seem to be directly impacted by the vulnerabilities fixed in this release.  The CHANGELOG goes into more detail on the fixes and updates addressed in this release.  Downloads are at the usual location.


New HOWTO Article on Setting Up JSessionID Persistence on a BigIP

This Howto was recently updated. Please see this post for more information.

This article serves more as a reminder for me than anything else, since I'm always forgetting the last step.  However, if it serves useful to anyone else out there...great!  

One of the first things I wanted to tackle when we got our spiffy new BigIPs in several years ago was persisting user sessions to tomcat or jboss application servers using iRules.  There are lots of examples of persisting traffic based on JSESSIONID, ASPSESSIONID, etc., but one thing that the budding application traffic manager may not necessarily realize from browsing CodeShare on F5's DevCentral site (login required) is that you don't (always) simply code an irule and attach it to your VIP.  There are a couple steps necessary and this new HOWTO article outlines those steps.

Go to HOWTO: Set Up JSESSIONID-Based Persistence on a BigIP now.