What you need to know: 1. Familiar with linux text editors 2. Have a basic understanding of load balancing 3. Familiarity with Apache, MySQL, and rsync 4. The ability to create at least 4 virtual machines What does this set-up provide? This set-up will provide you with some very basic failover at the web servers by using a load balancer. Keep in mind I will not be discussing HA at the load balancer level so you will still have a single point of failure with this guide, as it is only intended to provide some fundamental knowledge on how to set-up a replicated and load balanced pair of web...

Today’s downtime was unfortunately caused by memcached being overloaded. After tracking down the issue I figured that my configuration could use a slight overhaul in order to prevent future issues like today’s. The basic resolution was to simply restart the service which brought the site back online. Simple enough, however I feel that if memcached cant handle the current load then there is probably a reason and it should be revised. Initial Configuration: Database Server - MySQL 5.0.77 - Memcached 1.4.5 Memcached(defaults): 64MB Cache 1024 Max Connections Listening on private IP As you...

So I received an email this morning from RedHat explaining that RHEL 6 has been announced and with it comes the discontinuation of the RHCT exam which they are replacing with the RHCSA (RedHat Certified Systems Administrator). Fortunately this does not invalidate the RHCT because RedHat feels that the similarities between the two exams are so close that they are converting all existing RHCT’s over to RHCSA’s effective January 1st 2011. Here is the email from RedHat: Red Hat has announced general availability of Red Hat Enterprise Linux 6. Effective with the release of version 6, we will no...

The second OpenStack summit is under way. So far the discussions appear to be very detailed, and have lots of contributors. There was quite a bit of debate around IPv6; As of this writing the Austin release of nova does not currently provide IPv6 support, however the Bexar release should contain “dual stack” which will allow it to support both IPv4 and IPv6 addresses. This is a major step moving forward because of the well known IPv4 shortage. The faster we can implement a solid IPv6 solution within OpenStack the better. All in all the summit is going well, and it seems we are going to be...

This article is a follow up to my original called “Coding for the Cloud” which focused on a broad range of topics and provided a high level overview of how to use the cloud by scaling your application in a linear fashion rather than relying on heavy duty hardware to power your servers. This article is going to focus on figuring out if your application is a good fit for the cloud or if it should remain on a dedicated hardware solution such as Co-location, Managed Dedicated Servers, or Unmanaged Dedicated Server. So.. Is your application a good fit for the cloud? Here are a few questions you...