For almost 20 years in IT, he’s constantly explored the evens and odds of various technologies, including different operating systems, SSO and authentication services, RBAC models, PKI and cryptography components, HTTP-based services, proxy servers, firewalls, and core networking components. His focus in these areas has always been security related and included the design, implementation and review of secure and high availability/high performance datacenters.
DevCentral got a chance to talk with Kai about his work, life and mastery of iRules.
DevCentral: You’ve been a very active contributor to the DevCentral community and wondered what keeps you involved?
Kai: Working with online communities has always been an important thing for me and it began long time ago within the good old Usenet and the predecessor of the Darknet. Before joining the F5 community, I was also once an honored member of the Microsoft Online Community and was five times awarded as a Microsoft MVP for Enterprise Security and Microsoft-related firewall/proxy server technologies.
My opinion is that if you want to become an expert for a certain technology or product, you should not just learn THE-ONE straight-forward method fetched from manuals, guides or even exams. Instead, you have to dive deeply into all of those edge scenarios and learn all the uncountable ways to mess the things up. And dealing with questions and problems of other peers is probably the best catalyst to gain that kind of experience.
Besides of that, the quality of the DevCentral content and the knowledge of other community members are absolutely astonishing. It makes simply a lot of fun for me to work within the DevCentral community and to learn every day a little bit more…DC: Tell us a little about the areas of BIG-IP expertise you have.
KW: Over the years, I successfully implemented BIG-IP LTM, APM, ASM, and DNS Service deployments for our customers. Technologically, I internalized TMOS and its architecture very well and I pretty much learned how to write simple but also somewhat complex iRules to control the delivery of arbitrary data on their way from A to B in any possible fashion.DC: You are a Principal Consultant for IT Security at itacs GmbH - a German consulting company. Can you describe your typical workday?
KW: Because of my history with Microsoft related infrastructures, my current workload is pretty versatile.
Over the last years, my F5 customer base has periodically grown so I would say my work is a 50:50 mix right now. I do F5 workshops, designs, implementations, second and third level support as well as configuration reviews and optimization of existing environments. I work with some big web 2.0 customers that have the demand to pretty much exhaust all the capabilities of an F5. This challenges me as a network architect and as an ADC developer.
I realize every day that working with F5 products makes so much more fun than any Microsoft product I have ever dealt with. So in the future, I will even more put my focus on F5!DC: Describe one of your biggest BIG-IP challenges and how DevCentral helped in that situation.
KW: In my opinion, the F5 products themselves are not that challenging – but sometimes the underlying technologies and the detailed project requirements are. But as long as those requirements can be drawn and explained on a sheet of paper, I am somewhat confident that the BIG-IP platform is able to support the requirements – thanks to the F5 developers who have created a platform which is not purely scenario driven but rather supports a comprehensive list of RFC standards which can be combined as needed.
For an example, one of my largest customers operates an affiliate resource tracking system with three billion web requests per day with a pretty much aggressive session setup rate during peak hours. I have designed and implemented their BIG-IP LTM platform to offload SSL-encryption and the TCP-connection handling to various backend systems using well selected and performance optimized settings.
Other scenarios require slightly more complex content switching, the selective use of pre-authentication and/or combination with IDS/IPS systems. To support those requirements, I developed a very granular and scalable iRule administration framework which is able to simplify the configuration by using rather easy-to-use iRule configuration files (operated by non TCL developers) which will then trigger the much more complex iRule code (written and tested by TCL developers) as needed. The latest version of my iRule administration framework (which is currently under testing/development) will be able to support a couple thousand websites on a single Virtual Server, where each websites can trigger handcrafted TCL code blocks as needed, but without adding linear or even exponential overhead to the system as the regular iRule approaches would do. The core and the configuration files of the latest version are heavily based on TCL procedures to create a very flexible code base and also conditional control structures, but completely without calling any TCL procedures during runtime to boost the performance dramatically. Sounds interesting? Then stay tuned, I am sure I will publish this framework to the CodeShare once it’s stable enough… ;-)DC: Lastly, if you weren’t an IT admin – what would be your dream job? Or better, when you were a kid – what did you want to be when you grew up?
KW: I was typing my first assembler code out of a C64 magazine at the age of 10, so I really wanted to be a developer and/or IT admin since then. But besides of my current job, I can also imagine being a racecar driver. I really have petrol in my blood and pretty much enjoy driving on the German Autobahn. As an alternative, I could also imagine being a cook. I really love cooking and enjoy awesome food!
DC: Thanks Kai! Just don't fire up that sterno while shifting gears!! Check out all of Kai’s DevCentral contributions and check out their blog websites: ops365.de, flow365.de and brandmysharepoint.de.