Russians says – “One is not a warrior at the battlefield”, meaning that one is just too small number for a real war. When the time of real battle is coming to your web site, it’s time to become a … farmer. The geeky one.
Web farm, or Network Load Balancing (NLB) cluster is when there are more than one web server behind a single web address. Of course, it’s not only about web – some other stateless resources can be scaled that way as well – DNS server, for example, or SMTP. However, the most popular use of NLB clusters is web, as most requests in the Internet are going through it.
Network load balancing clusters are rather frustrating topic for many systems administrators, as it’s very common for them to know clustering till the time of their exam. MCSEs and MCITPs of all kinds have to know that stuff, but rarely use it. Who might be more interested in clustering – that’s web developers, who’s web applications serve more and more visitors each day and should be infinitely scalable by design.
But what it takes to build an application, which could be scaled out by simply adding more hardware? If your application is working fine and attracts more customers than it can handle – that’s when you are wondering whether you’re in trouble. The trouble comes when you realize, that the architecture of your project does not support scaling and situation is even worse if your web developer has no clue about how to make it work in the cluster.
For .NET developers, though, the situation is much better than for PHP developers, for example. They can use SQL server to store the state data (and SQL server may reside on failover cluster, which is the second type of windows cluster that we’ll review later), files can be stored at mirrored network area storage (NAS) and that’s it.
For administrators, though, the situation is more difficult. First of all, they are the ones who needs to care about installation, maintenance and management of the cluster. They are the ones who migrate old applications to new clustered servers and must ensure they understand why these applications do not work under new conditions. While usually developers have the harder burden, this time it’s not the case, thanks to Visual Studio and .NET.
There is not much we can say about developer’s part of the job, as there is too little and too simple stuff to do, there is pretty much to say and to show to system administrators.
That’s why I had no choice than to prepare my first narrated lab about creating Windows Server 2008 Network Load Balancing cluster. Enjoy!
Implementing Network Load Balancing Clusters in Windows 2008
Perhaps my future labs will become narrated as well, excerpt for the short and simple ones. It takes a bit more work, since I am not preparing the text and have limited time to complete the lab (always do it in one take), but is definitely more fun, as I can tell more than you want / need to know about the subject.