mark's blog

Redhat has put a lot of effort into making all types of clustering from load-balancing to shared storage and high-availability a core part of its Linux offering. Their solution for a load-balancing cluster with fail over, is the combination of "Linux Virtual Server" (LVS) with "Pulse" for fail over manager and "nanny" for cluster membership management.

Building a load-balancing, highly available (HA) cluster with Linux means your company doesn't have to spend big bucks to scale your application with increasing demand or to ensure critical services never go down. Most corporates respond to stringent service level requirements or poor application performance by buying larger, more expensive, machines or worse, turning to a proprietary load-balancing or ha appliance. 

At the last Ferndale Java User Group meeting on the 26th July 2010, I gave a presentation on Tomcat performance tuning and configuration. It seems that Tomcat is being adopted at an increasing rate by enterprises around the world as they abandon the complexity and hefty price of the Java application servers as pushed by the major JEE vendors such as Oracle and IBM. Lighter is better it seems :)

NetBeans is one of the most popular Java IDEs and Rich Client Platforms (RCP) in use today. What is a RCP you may ask? A RCP is a desktop application framework, much like a web application framework, that eases the burden of developing rich desktop applications by taking care of the standard plumbing code that is necessary for any desktop application. Think menus, windows, view and model syncing etc.

Tomcat is one of the most widely used servlet containers on the planet but many are unaware of how to tune Tomcat for maximum performance. The best place to get more performance out of your application though, is to look at the application code itself as a request spends around 80% of its time there rather than in Tomcat's code.

Ok, so after about two years we are trying to revive the Ferndale Java User Group. Our next meeting will be on the 30th June 2010 at the Bright Water Commons, Scrooges Diner. Please signup at fjug.co.za  and sign up to attend!

Just a quick note in case there is anyone else out there struggling to setup openwrt's Kamikazi dnsmasq server to hand out a default gateway and dns server other than the default. In the old days it was easy enough to just edit the dnsmasq.conf file but with Kamikazi you will want to edit the /etc/config/dhcp file to change default options.

More times than I care to mention I find myself having to battle with libvirt taking over my iptables rules and starting its own instance of dnsmasq, which just ends up ruining my whole day. Libvirt is a great abstraction layer for virtualisation, and although its xml config format and command line interface are well documented, how it works under the hood is less so.

Recently I got a new HTC Desire, the Google phone or Nexus One, in the rest of the world. I was faced with the perennial problem of getting my contacts off the old phone that had been in service for 3-4 years and onto the Android device. There was no easy way to do this, especially since I run Ubuntu. Luckily I am a JME developer and soon verified that the Nokia E70 supported JSR75, which allows for access to the mobile phones address book, and the ability to write files to local storage on the phone.

Jumping Bean is happy to announce the release of Calamari, a squid log file analyser application. The application has been released under the GNU Public License V3. Calamari consists of two components, a JavaFX front-end and a Java based back-end web service. It is designed to allow system administrators to easily identify anomalous events and drill down into the detailed log entries.