SELinux - An Introduction Presentation

"SELinux - An introduction" was the title of the presentation I gave this evening, 26 March 2012, at the Jozi LUG. SELinux is one of those Linux features that many administrators quietly turn off so as to get on with the business of managing their servers; but of course its not considered polite to say this in public.

With the targeted policy there really is no reason why SELinux cannot be used by default in most installations with the strict policy only being used if it is really required. Of course there is also apparmor that can be used.

Redhat EX300 Exam Lab

We will be sending our instructors to take the EX300 Redhat exam soon and thought it would be good to record some of the labs we have them complete in our training labs. Whilst some of the lab are easy to generate like setting up Apache virtual servers, DNS, SAMBA etc the following test several areas of knowledge required for EX300.

Maven Hibernate 4.0.1 pom.xml - Dependencies (POM.xml)

I have been avoiding using Hibernate for a while now. I have been using alternatives such as the reference implementation, eclipselink or Apache's openjpa. But I have to keep up to date with Hibernate for our JBoss training sessions, where the more developer focused training sessions, often cover examples of hibernate with JBoss for EJBs.

JBoss Datasource Password Encryption/Hashing

In my previous post on JBoss password encryption I showed how to encrypt passwords for services that make use of the Jboss microcontainer. These services are configured in files that end with the suffix *-jboss-beans.xml. As stated in that post JBoss has a tendency for inconsistency in its configuration files and service setup due to its migration away from the JMX Kernel to the Microcontainer and its historical use of custom XML files for some setups like data sources.

JBoss Password Encryption For Microcontainer Beans

JBoss 6 can make use of a centralised java keystore to save all the passwords needed in configuration files in a single place thereby making them easier to manage and protect. No more worrying about clear-text passwords in xml files! This feature is only available to services that make use of the microcontainer for service instantiation as it uses the microcontainer annotations.

Optimising Website Performance on Apache with Cache Control Settings

When tuning a web site running on Apache for optimal performance there are two places to look. The first is picking the right combination of settings for the muli-processor module (MPM) you have selected and the second is tweaking the various settings that affect the caching and compression of web application content.

Tomcat Performance Tuning SA Oracle User Group Conference Presentation 2011

In October 2011 I gave a Tomcat Performance Tuning presentation at the Oracle South Africa User Group (SAOUG) conference hedl a Sun City. The confernce was attended by over 800 delegates and saw the addition of a Java track for the first time this year.

XBMC, Ubuntu 10.04 LTS and Nvidia GeForce G210 (Ninja)

Its the end of the year again so I got some time to do complete a few projects, like build a media centre for the house. I got several TVs around the house and need a conveninet way to play movies on any TV in the house from a single source. The solution is to build a uPnP media source and then several media centres, 1 for each location.

JPA 2 Criteria API Tutorial

When JPA 2 was released in 2009 it included the new criteria API. The purpose of the API was to get away from using JQL strings , (JPA Query Language), in your code. Although JQL seems like a great way to leverage your existing SQL knowledge ,in the OO world it has a major drawback  namely;  there is no compile time checking of your query strings. The first time you find out about a spelling or syntactical error in your query string is at run time. This can be quiet a productivity drain with developers having to correct, compile and redeploy to  continue.


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