2 posts categorized "devop"


Systems Admins R.I.P. - MuleSoft Blog

Back on January 20th, 2011, Ross Mason, MuleSoft Founder, posted an article on the company blog, From the Mule's Mouth, titled "Systems Admins. R.I.P.?", which became popular this week due to it being posted on many aggregation sites and is filled with some lively commentary by many sysadmins around the world.

As I sit here waiting for the Cloud to rapture me off to the Choir Invisible, I can't help but think of those that fell before us. Who can forget back in the mid-70's when Digital Equipment Corporation's proclaimed the death of the mainframe with the introduction of mini computers and the effect it had on mainframe systems engineers.  There are none left.  They are all gone.  Remember when Microsoft introduced Windows NT Server?  That's the day we lost all the UNIX administrators. 

Perhaps they were the lucky ones because the hype around Cloud Computing is so great, this may be one of the greatest extinction events ever.   

All kidding aside, I do feel sorry for the MuleSoft systems administrator alluded to in the article. When the founder of your company publicly wonders what you do, you have a very tough job.


Updated Howto: Setting up BigIP for JSESSIONID-Based Persistence

I updated the HOWTO: Set Up JSessionID-Based Persistence on a BigIP article recently to reflect some additional changes/discoveries made while running this in a production environment for a while.  The howto covers migrating off of apache/mod_jk to apache/mod_proxy and moving persistence based on jsessionid to a bigip ltm.  

If you are a developer reading this and wondering why in the world anyone would want to move away from mod_jk, the rationale behind the migration is pretty straightforward:  When you have more than a couple web servers front-ending your tomcat, glassfish, or jboss application servers, or even if you only have a couple of web servers but a lot of workers defined within your workers.properties files, disabling servers using the jk-status handler page can be a real hassle.  Training 1st or 2nd level support personnel within your network operations center on disabling servers in a bigip is much easier than showing them how to disable workers within a jk-status page. 

In addition, the BigIP enables the DevOp or Application Delivery Engineer to create more sophisticated health checks to assess app server health over mod_jk's cping/cpong.  A well written health monitor on the bigip is much better able to assess if an app server is hung than mod_jk's health checks at present.  A BigIP health check can assess almost instantly when a java application server is hung where requests using the traditional mod_jk approach must wait until the ajp backlog threshold has been reached, which could result in a lot of request hitting a hung application server unnecessarily.

Changes to the document include information on why oneconnect is necessary as well as mod_proxy-specific environment variables that should be set in order to avoid 502-Proxy Errors showing up in your apache error log during periods of low site activity.