iRules

Election Hash Load Balancing

DevCentral TV — Thu, 26 Jun 2008 16:51:01 GMT

F5 Solutions Architect Nathan McMahon explains Election Hash Load Balancing And Persistence (find the iRule in the codeshare here). He developed this Election Hash solution to address the limitations of the Cache Array Routing Protocol, and it provides a nice alternative to any typical hash solution that are vulnerable to re-factoring on changes to the server pool. The complete solution is written up here: Hash Load Balancing and Persistence on BIG-IP LTM

This solution was brought to you by the iRules commands: md5, HTTP::uri, and active_members

Technorati Tags: F5, DevCentral, iRules, Election Hash, Load Balancing, Nathan McMahon

Universal Persistence with SSL Offload

DevCentral TV — Wed, 25 Jun 2008 16:25:25 GMT

F5 Field Systems Engineer Christopher Schaefer sits down with Colin & Deb to explore an interesting iRules solution: Persistence for mobile devices running a proprietary stateful TCP application while roaming across cell towers mid-session. In the absence of a consistent IP address or any identifying header information, Chris discovered the client mobile ID embedded in the binary data of the traffic stream, and built a custom Universal Persistence solution. This solution was only possible because of the SSL offload capability of LTM, which allows LTM to decrypt the traffic before examining and acting upon it.

This solution was brought to you by the iRule commands: persist , TCP::collect, and TCP::payload, and the Tcl command binary

Technorati Tags: F5, DevCentral, Persistence, SSL, LTM, Christopher Schaefer

Active-Active Database Load Balancing

DevCentral TV — Thu, 19 Jun 2008 15:16:43 GMT

F5 Field Systems Engineer Patrick Chang explains an iRules solution that supports 2 active database instances in different data centers behind a web application. The goal is to provide the optimal user experience by load balancing requests for both the web/application tier and the database tier to a local data center whenever possible. Since cross-data center database replication takes approximately 20 seconds, one instance is preferred for database writes, and an iRule that reads and inserts time-stamped cookies reliably directs traffic to the closest database instance when possible, and to the remote instance only when necessary to maintain session integrity.

This solution was brought to you by the iRule commands: HTTP::cookie, HTTP::uri, and HTTP::method

Technorati Tags: F5, DevCentral, iRules, Database, Patrick Chang

DC Post of the Week - Switch Gone Wild

DevCentral TV — Fri, 13 Jun 2008 18:18:03 GMT

“Switch” Gone Wild

This week Deb looks at a post from gregt, who was having some trouble with choosing a pool based on the requested URI.

Posters aherrman and cmbhatt (CB) jump in to correct the logical order of comparisons (most specific first, please!). CB further suggests using switch with wildcards to replace the nested “if” commands that used “starts_with” and “ends_with”.

You’ll probably want to pull up the post to follow along on this one, so here it is: iRule sends to wrong Pool and Port

Technorati Tags: F5, DevCentral, Post of the Week, DCTVPOTW, switch

DC Post of the Week - Disposing Your Content

DevCentral TV — Thu, 05 Jun 2008 16:29:13 GMT

Disposing Your Content Properly

This week Colin & Deb take a look at a post from gerardo.garcia in which he ask if there is a way to force a document download instead of having recognized content types displayed in the browser automatically.

Hoolio & Colin offer a simple iRule solution involving the HTTP::header command and the Content-Disposition header.

Here’s the post: Content Disposition

Technorati Tags: F5, DevCentral, Post of the Week, DCTVPOTW, HTTP, Content-Disposition

DevCentral EMEA Tour 2007, Episode 2

DevCentral TV — Wed, 26 Sep 2007 23:45:25 GMT

In this next installment of Colin's European tour, Sam Pickles is kind enough to take time out of his day between presenting, answering questions and generally assisting with the CoE in general to talk to us about an interesting experience he had in a bake-off. iRules helped seal the deal again, along with BIG-IP and TMoS and their astounding performance.

The requirement is 65K connections? Sure, we can do that. How about 200K instead? 'Nuff said.

DevCentral EMEA Tour 2007, Episode 1

DevCentral TV — Fri, 21 Sep 2007 21:23:49 GMT

In this video, which is the first in a series of 3 videos captured on Colin's recent trip to Europe, we talk with one of F5's partners, Nebulas Security, to discuss how they're making use of F5's technology in interesting ways. As it turns out, they've recently used F5's iRules technology in a system migration to avoid large amounts of extra work and/or disruption in the client experience.

iRules in the hands of a partner - pure power

DevCentral TV — Mon, 19 Mar 2007 15:03:22 GMT

In this DCTV episode, the Director of Technology for Symphoniq walks us through some of what they do, why it's cool, and how they make use of the BIG-IP and iRules.

Features: New iRule Editor makes it faster and easier to edit, backup even deploy iRules

DevCentral TV — Mon, 12 Jun 2006 08:26:00 GMT

Joe Pruitt takes us on a deep dive through the brand new iRules Editor, just released on DevCentral. On this detailed walthrough we cover everything from the history of the Editor to the process of building it, all the way through each of the numerous cool features that are packed into this lightweight, easy to use package.

Announcing the iRules Wiki, new from DevCentral!

DevCentral TV — Tue, 31 Jan 2006 02:10:00 GMT

The DevCentral team has been working hard to answer the call from our customers and partners for expanded iRule technical information and documentation. In response, we are proud to announce the DevCentral iRules Wiki – a new section of DevCentral designed to help answer this call. Jeff Browning interviews Colin Walker to get a brief rundown on what the Wiki is, what it includes, and how you can contribute your examples!