Colin Walker

DevCentral Top5 06/05/2009

Colin Walker — Fri, 05 Jun 2009 21:07:49 GMT

It's been busy! The DevCentral team and all of the awesome people in our extended family have been working away, putting out all kinds of great content for your perusal. Now that we're out of the hardcore v10 push and back into a more "normal" flow of content there has been a myriad of tasty morsels flowing through the DC channels. From a posh search experience to security secrets and new wrappers, we've had plenty to talk about. Let's get to this week's Top5:

The Secret of the Security Safety Dance

http://devcentral.f5.com/weblogs/macvittie/archive/2009/06/03/the-secret-of-the-security-safety-dance.aspx

This week Lori made me literally laugh out loud with the analogy she chose for this post. Not only did she make a valid point about security but she did so while tapping into my beloved WoW culture enough to make me chuckle and shake my head…appreciatively of course. In her post Lori talks about how attackers work together to find and exploit vulnerabilities, spreading that information like wildfire. This presents some serious benefits to be had, bordering on requirements, for an infrastructure agile enough to cope with and defend against these attacks. I toyed with the idea of featuring her "Facepalm: Google Wave Choice of XMPP Not the Death of HTTP" post, as it's possibly more technically relevant and compelling, but the humor in this one won me over. Do yourself a favor and check them both out.

Ruby iControl Wrapper

http://devcentral.f5.com/weblogs/jason/archive/2009/06/04/ruby-icontrol-wrapper.aspx

Jason's been hard at work this week, pumping out a couple of great tech tips and blog posts. The first I want to feature is a cool example of more Ruby goodness with iControl in mind. Jason tried on his Ruby Developer's hat long enough to post up some info about a community contributed wrapper as well as an example of making use of Ruby to grab some pool info. The post itself is good but the underlying info on the wrapper is the real meat of the matter. Dig in and take a peek. I'm always intrigued by new ways to use iControl from interesting languages. Hint: There was some great python + iControl content this week too.

Introducing PoshBing - The PowerShell library for Microsoft's Bing Search Engine

http://devcentral.f5.com/weblogs/Joe/archive/2009/06/03/introducing-poshbing-ndash-the-powershell-library-for-microsoftrsquos-bing-search.aspx

Joe, in his usual "It's all blue sky…" fashion, has dabbled in the API for Microsoft's new Bing search engine this week. He's given you a kind of library to allow you to easily make use of the multiple searching facilities provided by the Bing engine, straight from an easy to use PowerShell script. While not directly F5 related, this was timely and interesting enough to make me re-read it and poke around a bit. It's worth a look, and might be useful to some people looking to integrate search into a windows deployed app somewhere. At the very least, the bing engine is very interesting and currently relevant, so learning more about it can't be a bad thing.

v.10 - Remote Authorization via TACACS+

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=2316

For Jason's next trick, he'll require an LTM, some remote users, and a couple of videos. Jason chose to dive into remote auth on the BIG-IP. Specifically, he's dealing with the tacacs+ config. He'll show you how to set it up, what user roles you have available to you, and he even has some very helpful videos to walk you through the process. If you've been waiting for an LDAP remote-auth alternative for your BIG-IP, this could be the ticket. Even if not, it's always interesting to me to check these things out. When it comes to hands-on, in the field BIG-IP experience, Jason has it in spades. Take a look, you'll probably learn something.

20 Lines or Less #24

http://devcentral.f5.com/weblogs/cwalker/archive/2009/06/03/20-lines-or-less-24.aspx

Last but never least, in my mind, is this week's 20LoL. This week I was working off of an encryption/hashing sort of theme. All of the examples fit into that vein, and are sweet examples of what iRules can do for you in a few lines of code. Whether you're trying to work out an SSL config that is more flexible, or you've been dying to get FNV hashing implemented, but just weren't sure where or how, or if you're just a geek like me and love this stuff, this one is worth a read. The 20 Lines or Less, to me, is an awesome showcase of just how powerful iRules can be in a real-world situation where huge, overwhelmingly complex scripts aren't an option. These examples continue to show that iRules can get the job done in a hurry. Thanks to the awesome community that keeps pumping out great things for me to feature here. Keep them coming.

There's your Top5 for the week. Hopefully you enjoyed it, as I always do writing it. Send in your comments, feedback and suggestions. And as always, check out previous versions on my team page on DC.

Technorati Tags: F5,DevCentral,DevCentral Top5,iRules,PoshBing,Ruby,iControl,20 Lines or Less,WoW,Colin Walker

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Categories: DC Top5 , DevCentral , iControl , iRules , Development / General IT Goodness , Microsoft Solutions , Ramblings , Security

20 Lines or Less #24

Colin Walker — Wed, 03 Jun 2009 18:33:39 GMT

What could you do with your code in 20 Lines or Less? That's the question I ask (almost) every week, and every week I go looking to find cool new examples that show just how flexible and powerful iRules can be without getting in over your head.

This week is apparently the week of encryption! I bring to you from my fellow DevCentralites a trio of encryption/hashing goodness via iRules. Two of today’s iRules were pulled from the samples page, one was recommended to me by Jason. All are very cool examples of iRules geekery and creativity, and they just happen to share a common theme. Even though hashing and encryption aren’t quite the same thing, they’ve always fell somewhere in the same region to me, so I’m lumping them together. I get to do that, it’s my blog. So roll up your sleeves for some hashing, non-decrypting goodness, and let’s go.

FNV Calculation

http://devcentral.f5.com/wiki/default.aspx/iRules/FNV.html

In the first of two hashing iRules that the ever crafty Nat has posted, he gives us a look at FNV hash formulation via iRules. What is FNV? Wikipedia will tell you all about it, just go take a peek.

when RULE_INIT {
    set fnv_hash 0x811c9dc5
    # 2166136261
    set fnv_prime 0x01000193
    # 16777619

    set fnv_str "teststring"

    for { set fnv_i 0 } { $fnv_i < [string length $fnv_str] } { incr fnv_i } {
        binary scan $fnv_str @${fnv_i}H2 fnv_str_i
        set fnv_hash [expr $fnv_hash ^ 0x$fnv_str_i]
        set fnv_hash [expr $fnv_hash * $fnv_prime]
    }
    set fnv_hash [expr $fnv_hash & 0xffffffff]
    log local0. "FNV HASH = [format 0x%x $fnv_hash]"
}

HMAC Calculation

http://devcentral.f5.com/wiki/default.aspx/iRules/HMAC.html

In his next trick, Nat shows us how to create a Hash Message Authentication Code (HMAC) via iRules. This one I had to massage a little to get in under the 20 line limit, and even then it just barely squeaks by. It was worth it though…cool stuff!

when RULE_INIT {
set input { "1234" "123456789012345678901234567890123456789012345678901234567890xxxx" "yyyy123456789012345678901234567890123456789012345678901234567890xxxx" }
foreach prekey $input {
    switch [string length $prekey] {
      "64" { set key [sha256 $prekey] }
      default { key $prekey }
    }
    set ipad ""
    set opad ""
    for { set j 0 }{ $j < [string length $key] }{ incr j }{
        binary scan $key @${j}H2 k
        append ipad [format %c [expr 0x$k ^ 0x36]]
        append opad [format %c [expr 0x$k ^ 0x5c]]
    }
    for { }{ $j < 64 }{ incr j }{
        append ipad 6 \\
    }
    binary scan [sha256 $opad[sha256 "${ipad}test"]] H* hextoken
    log -noname local0. [string toupper "result = $hextoken"]
}
}

HTTPS Passthrough Fallback URL

http://devcentral.f5.com/wiki/default.aspx/iRules/HTTPS_passthrough_fallback_URL.html

This example was pointed out to me by Jason and is brought to you courtesy of the ever active hoolio. This is a very cool way to pass SSL traffic without decrypting, yet hang on to some failover and redirection capabilities if things go down. Dig it.

when CLIENT_ACCEPTED {
   log local0. "[IP::client_addr]:[TCP::client_port]: Received connection with active members: [active_members [LB::server pool]]"
   # Check if there are members available in the VIP's default pool
   if {[active_members [LB::server pool]]}{
      # Disable the client SSL profile so the HTTPS traffic is passed through encrypted to the node
      SSL::disable
      # Disable the HTTP profile as we're not going to redirect this request
      HTTP::disable
      log local0. "[IP::client_addr]:[TCP::client_port]: Members available"
   }
}
when HTTP_REQUEST {
   # The HTTP_REQUEST event is only triggered if the pool members are down and the client SSL and HTTP profiles are left enabled
   # Redirect the client
   HTTP::redirect https://maintenance.example.com
   # Close the TCP connection so that the pool is checked for every HTTP request
   #   This should prevent clients from being continuing to be redirected after the pool comes up
   #   (which would happen if they re-used the same TCP connection).
   TCP::close
   log local0. "[IP::client_addr]:[TCP::client_port]: Redirecting request"
}

Thanks to everyone that keeps on contributing awesome iRules. It’s a privilege to get to write about them. Keep ‘em coming, and let me know if you’ve got any questions or suggestions.

Technorati Tags: DevCentral,20LoL,20 Lines or Less,F5,iRules,hoolio,Jason Rahm,FNV,HMAC,SSL,Colin Walker

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Categories: Ramblings , iRules , DevCentral

Ring Ring Mr. Interoperator

Colin Walker — Thu, 21 May 2009 22:30:46 GMT

It’s been a great week at Interop in Las Vegas. I’m sitting here at the airport, sipping a frosty beverage and recalling the events from the past few days, and I have to say it’s been worth the last-minute trip.

Each day I gave an iRules talk at the F5 booth. I got to do my song and dance in front of a crowd of people and try to express why iRules are so amazing to them, and why they should be using them. That’s pretty much a description of every day for me, it seems. The twist this time was that I only had five minutes per session. Five minutes?!? How am I supposed to express the limitless amount of hawesome contained in iRules, let alone F5 gear as a whole, in a mere five minutes? This was new for me, and it was quite a fun exercise.

I think I managed to pack in a fair amount of content and, more importantly, pique peoples’ interest enough for them to swing by afterwards for deeper conversations. I was, as I mentioned more than once, “armed with a white-board and markers, and not afraid to use them”. These one on one (or sometimes one on a few) conversations at the booth were very cool. The people I talked to ranged from the completely uninitiated to the F5 veteran. It was great seeing a diverse mix of people and watching all of them get the “A ha!” moment at one point or another. There’s no denying that the stuff we’re doing as a whole, including my beloved iRules, are amazingly useful. Once people understand the things we can do, there isn’t one of them that doesn’t seem somewhere from intrigued to desperate for our help.

One of the major benefits that I hadn’t thought about before coming down here was the chance to connect with fellow F5ers that I don’t see on a daily basis. There were great conversations, some impromptu meeting type discussions and some brain-storming for what should come next. It’s always good to get together with like minded folks and riff. If you were following me(or #F5Interop) on twitter you know most of this, though, as I tweeted plenty while at the show, as did many of the other F5 folks.

If you were at Interop this year and I got the chance to chat with you, thanks for swinging by. I know at least a handful of people I talked to were fully DevCentral aware. Heck, one person even said he listened to our podcast every week. Good stuff.

Were you there? Have you been previous years but missed out this time? What were your impressions. Let me know what you thought; from favorite gimmicks to booth impressions to coolest swag, I’d love to know what your experience was. I’ll be back in Seattle late tonight and catching up on email and the like tomorrow, so expect a Top5, and then plenty more chatter next week.

Technorati Tags: F5,DevCentral,Interop,F5Interop,iRules,Twitter

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Categories: Cloud Computing , DevCentral , iRules , Ramblings

Countdown to Interop: T minus 1

Colin Walker — Fri, 15 May 2009 22:21:51 GMT

It’s Friday, the last day of work before taking off (literally) for Interop Monday morning. It’s been insanely busy trying to get ready to leave. So busy, in fact, that I somehow managed to miss T minus 2 in the series. Oh well, I was likely working on one of my presentations for next week, the presentation I gave this morning at 9, my blog, getting video gear together or … something.

I leave super early out of Seattle, so you won’t hear from me until I’m settled into my room in Vegas. I’ve got my presentations finished, I’ve sent them off to the appropriate people, I’ve slogged through the meetings and emails to get things cleaned up for when I’m gone. You know, so I have a fresh pile of stuff to go through when I get back. Not the same old stuff from before. Because that’s, you know, better.

My topics are set, which is a good thing, since my presentations are already done. I’ll be talking about both “iRules Event Order De-mystified” and “iRules Classes – What’s good, and what’s new?”. Snazzy titles, eh? I know, I’m no marketing guy, but I promise there’s some goodness in them. These are pretty quick talks, but I’m going to be hanging around the white-board at the booth afterwards for a couple of hours to get as deep into any questions you might have. iRules, iControl, BIG-IP in general, bring them all, we’ll crunch through them, and leave none behind! Or so I hope anyway. If I can’t answer one of your immediate questions there’s a good chance one of the other folks at the booth can. Worst case scenario, I’ll bring it back with me and write about it the next week so we all get the answer.

I finally got a finalized version of the schedule for my presentations while I’m in Vegas. Come by booth #1931 at 11:30AM Tues-Thurs. to see me give a quick chat about iRules goodness. Then stick around for some white-boarding madness afterwards. If there are questions right away, I’m happy to dive right in. Otherwise, I’m planning on manning the white board at 1PM each day if I have some folks wanting answers.

I’m planning on hanging around the booth from 10:30-2, so you can catch me there if you’ll be around. There will also be a host of other great F5ers there to answer any questions I might not be up to speed on. Make sure to swing by if you’re going to be in the area. Much geekery will be had, and as I’ve promised before, invitations to a reception with free food and tasty adult beverages. Code, food and beer - what more could you ask for?

I’ll try to keep you updated on what’s going on, so stay tuned here, on twitter (colin_walker) and make sure to follow the #F5Interop tag on twitter to see what everyone else at F5 is up to regarding Interop this year.

Technorati Tags: F5,DevCentral,Interop,F5Interop,Colin Walker

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Categories: DevCentral , Development / General IT Goodness , Ramblings

Countdown to Interop: T minus 3

Colin Walker — Wed, 13 May 2009 20:43:37 GMT

It’s Wednesday already, and it feels like the week has just flown by. I’m finishing up my presentations and getting things together to leave. I got a copy of the schedule for who’s going to be talking about what next week, and I’m quite pleased to be in great company. Fellow DC bloggers Lori and Alan will be there, along with several other sharp F5 folks talking about a myriad of interesting stuff. Hopefully some of them will keep the geek level high enough for our fellow engineer types.

It’s always interesting to me trying to put together content for something that’s not only a short presentation, but pretty “marketing-y” as well. I often wrestle with making things look good and go down smoothly without dumbing down the content. I’m actually really happy with the results I’ve gotten so far. I think there’s enough tech in there for me to talk about, and there’s even some code (like there was any doubt). All of that wrapped in a shiny, happy wrapper that will look snazzy (by my normal standards at least) and hopefully catch a few people’s attention.

This afternoon I’ll finish polishing up the already finished presentations and complete the last one so it too can be buffed to a radiant shine. After that I need to dive into the 20LoL to try and get that out tomorrow morning before the podcast. Then there are about three articles that need writing, a video to shoot, forum posts to answer…you get the idea.

There always seems to be twice as much to do as there is time, before I go out of town. Does everyone else wrestle with this too when prepping for a trip? I can’t be the only one.

Technorati Tags: F5,DevCentral,Interop,F5Interop,Colin Walker

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Categories: DevCentral , Development / General IT Goodness , Ramblings

Countdown to Interop: T minus 4

Colin Walker — Tue, 12 May 2009 23:25:07 GMT

It’s the second day of my Interop countdown, and there’s plenty of buzz coming from those getting ready for the show.

I had a meeting with one of the people here helping to manage the show from our end to discuss time-frames and scheduling, when to be where, topics I’m going to talk about, who else is going to be there at similar times … even what shoes to wear. Apparently that’s caused many a newcomer to the convention scene grief. Lucky for me, I’m a seasoned vet and merely grimaced at the “he bought new shoes for the show” story, knowing just how bad of an idea that really was.

If you haven’t chimed in on my poll in the forums to let me know what topics you want to hear about most, feel free to do so and also drop me a line with anything else you might want to suggest, or even just a hello if you’re heading to the show yourself. If any of you are going to be there I’d love to catch up and talk geek. I’m going to be armed and dangerous with not only a white-board and the necessary implements of destruction (well, markers anyway), but also with invites to the F5 reception thing-a-ma-jig that’ll be going on Tuesday evening. It’ll be a great chance to get to catch up with F5ers, your peers, and most importantly, free food and drinks. Hey, I know what sells…

So now it’s back to trying to catch up with my “day job”. It looks like I’m going to get a chance to dig into tmsh much more deeply in coming weeks, which is very cool. I got a sneak peek today at some very hawesome functionality that you’re going to love. As soon as I get the green light, I’ll make sure to share. For now though, all I can say is that I WANT. Look for a 20LoL tomorrow, and a Top5 on Friday (I was out last week). Next week will be mostly updates from Interop, but I’ll make sure to sneak in some geek, too. ;)

Oh, and don’t forget to get your twitter clients ready to follow #F5Interop for live updates.

Technorati Tags: F5,DevCentral,Interop,F5Interop,iRules,Colin Walker

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Categories: DevCentral , Development / General IT Goodness , Ramblings

Countdown to Interop: T minus 5

Colin Walker — Mon, 11 May 2009 22:57:10 GMT

Today I begin my five day countdown to Interop 09. I’m finalizing thoughts on presentation ideas, making lists of things to do both at work and around the house before flying down to Las Vegas on Monday for the show, and getting all of my other projects to a stopping point so I can leave them for a week. Interop should be a good show this year, as it always is. It’s huge, and there are always some interesting things to pick up there, as well as cool people to meet up with.

I’ll be attending this year to give some talks on cool geek filled stuff like iRules and v10 goodness that we’ve talked about here in recent weeks on DevCentral. I’ll have a few different short presentation time slots throughout the week. You’ll also be able to find me at the white-board at the F5 booth on the floor for some more down and dirty tech discussions. We’ll break out the multi-colored markers, get to diagramming, mocking up code, and all that great geekorific stuff that I love to do.

If you’ll be around at the show, be sure to come check out the booth and one (or some) of my presentations. I’ll be counting down the days until then here, and will get you a schedule of where I’ll be, when, etc. so you can come hang out. I’ll also be posting what is possibly the most valuable information of all – where to get some free drinks. Stay tuned for that gem later in the week.

For now, though, it’s back to narrowing down what topics to talk about and squaring up the last of my travel details. I’ve got a post up in the forums where you can weigh in, so go check it out and let me know what you think. Also, if you’ve got any ideas on things you’d like to see from the show, topics you’d like to hear talked about in “feet on the street” style interviews, or anything else that you think would be cool while I’m down there, let me know.

You’ll be able to check out some real-time info about what’s going on via twitter, so add the #F5Interop hashtag to your tweetdeck or twitteriffic or … whatever, and keep up with the latest. More tomorrow.

Technorati Tags: F5,DevCentral,Interop,F5Interop,iRules,Colin Walker

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Categories: DevCentral , Development / General IT Goodness , iRules , Ramblings , v.10

DevCentral Top5 05/01/2009

Colin Walker — Fri, 01 May 2009 22:25:41 GMT

From Web Accelerator to iRules to the release of the new Management Pack, this week's Top5 has it all. As always, there was plenty going on this week on DevCentral. These are my picks that you've just got to check out. Whether it's because they're incredibly useful, interesting, or just plain cool, all of these are worth a read, or listen, as the case may be. Here's this week's Top5:

Announcing the Release of the F5 Management Pack for Microsoft System Center Operations Manager 2007

http://devcentral.f5.com/weblogs/sfisher/archive/2009/04/28/announcing-the-release-of-the-f5-management-pack-for-microsoft.aspx

Aside from being the longest title of anything I've ever put in the Top5, this post represents the very cool release that was the big news for us here on the DevCentral team this week. We are quite happy to be able to help release the Management Pack on DevCentral. The management pack is a software plug-in that gives you access to a host of information about your BIG-IP. This post by Stephen, one of the killer developers here at F5 responsible for the Management Pack, gives a description of what it is, how to get a hold of it, and where to read more. You can also check out the very handy installation tutorial here - http://devcentral.f5.com/weblogs/dctv/archive/2009/04/28/tutorial---management-pack-installation.aspx for a video walkthrough of getting started. Check out all the Management Pack related content we've got, as it updates, at http://devcentral.f5.com/mpack

v.10: WebAccelerator Enhancements

http://devcentral.f5.com/weblogs/jason/archive/2009/04/30/v.10-webaccelerator-enhancements.aspx

Version 10 coverage has been thick on DevCentral since release. We've talked about all sorts of changes and upgrades to iRules, iControl, licensing, GTM, LTM and more. Now you can add Web Accelerator to that list as well. Jason dives into some of the awesome changes to WA in v10, touching on handy features like Signed Acceleration Policies, as well as more core functionality changes like true integration into TMOS. Bygone are the vip-sandwich days, WA has made it fully into TMOS which just opens the door for better performance and deeper integration. This article is particularly interesting to me given my recent work with Web Accelerator thanks to the Real IT project the DC team has been working on most of the year. It's great to see WA getting some v10 love as well and, as always, Jason does a great job as your tour guide.

v.10 - Introduction to iSessions

http://devcentral.f5.com/weblogs/dmacvittie/archive/2009/04/29/v.10---introduction-to-isessions.aspx

Another very cool feature that's new in v10 is iSessions. iSessions are, in the simplest possible terms, a way to create a secure tunnel between two BIG-IPs. That, in and of itself, would be cool enough…but wait, there's more! These secure tunnels are also optimized to allow increased performance between BIG-IPs. Extrapolate on this a bit further and suddenly you're talking about secure, optimized connections between not just two systems in a datacenter, but quite possibly between different data centers. Interested yet? I know I am. In this post Don walks us through what iSessions are, what they can do and promises more information soon. I'll be staying tuned to learn more about this cool new feature, since it sounds like there are some very cool possibilities here.

Virtual Reality

http://devcentral.f5.com/weblogs/macvittie/archive/2009/04/28/virtual-reality.aspx

Weighing in on the topic of virtualization, Lori postulates that - "You can't afford not to invest in technologies that leverage virtualization to improve data center efficiency". She goes on to make some strong points about how now more than ever it's important to think about spending some money in the DataCenter to save big in the long term via virtualization and improved efficiency. She details the areas in which CIOs report that they will be investing over the next year, including information security, virtualization and data center efficiency. All of these things, of course, benefit from application delivery, which is good news for us. Whether it's to build in better efficiency today or to plan for tomorrow, Lori's comments make a lot of sense (cents?).

20 Lines or Less #23

http://devcentral.f5.com/weblogs/cwalker/archive/2009/04/27/20-lines-or-less-23.aspx

Continuing with one of my favorite pastimes on DevCentral, I dished out another 20 Lines or Less this week. As always, I bring three more cool examples of how to use iRules that do interesting things in less than 21 lines. This week I've got some HTTP version modifications mid-stream, LTM served responses based on a request URI, and a cool trick to make dealing with favicons a little easier. If you're looking to see what kinds of things can be done with iRules in just a few lines, I highly recommend this series. Keep the awesome examples coming, as this one is almost solely driven by community examples.

There you go, my favorite five things from DevCentral for the week. Thanks for reading.

Technorati Tags: F5,DevCentral,Top5,iRules,Web Accelerator,iSessions,Virtualization,20LoL,Colin Walker

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Categories: DC Top5 , DevCentral , iRules , Microsoft Solutions , v.10 , Ramblings , Monitoring/Management

v.10 - iRules Content Recap

Colin Walker — Wed, 29 Apr 2009 19:52:51 GMT

As you've no doubt seen by now, BIG-IP v10 has brought with it all kinds of powerful new features. Among those are some very cool changes to iRules. I've already talked about the new class command, the killer new after command and a brand new namespace for you to utilize in your iRuling endeavors. These are far from the only additions to iRules in v10, however.

If you're familiar with our iRules Wiki, then you'll likely notice that the new commands are already showing up in the appropriate places. They're both in the main commands page, as well as their respective pages based on namespace and/or command type. There is also, however, a brand new page in the wiki that shows off all of the new v10 commands in one spot. Check out the "New in Version 10" page for all of the v10 commands rolled into one easy to find page. I'll continue putting out docs and blogs on individual commands in coming weeks, but wanted to make sure you knew where to find all the info you need to start playing with the new features yourself.

So to recap:

Check out the new class command, the amazing things you can do with it, and an explanation of the changes and how they work. - TechTip
Learn about the awesome new after command that allows you to delay the execution of iRules code, making for some very cool possibilities. - TechTip
Read more about the new static namespace in iRules and how you can make use of it for the best CMP performance possible. - TechTip
Be sure to dive into the NewinVersion10 wiki page for a list of all the new iRules toys added in BIG-IP v10. - WikiPage
And last but not least, stay tuned as there are plenty of iRules Tech Tips, blogs, examples and more on their way.

Technorati Tags: DevCentral,iRules,F5,v10,BIG-IP,class,after,static,Colin Walker

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Categories: DevCentral , iRules , Ramblings , v.10

20 Lines or Less #23

Colin Walker — Mon, 27 Apr 2009 21:04:34 GMT

Catching up with a couple weeks of iRules goodness, I've got some cool ones for you again this week. I'm happy to see people are adding plenty of handy iRules in the CodeShare. It doesn't just make my job of finding cool, succinct iRules easy, it makes your lives as iRulers easier, and that's far more important. Keep it up guys, you're rockin'. Here are a few more in under 20 lines for you:

HTTP Serverside Chunking For One Dot Zero Requests

http://devcentral.f5.com/wiki/default.aspx/iRules/HTTPServersideChunkingForOneDotZeroRequests.html

This is a pretty cool iRule that lets you control the HTTP version for the server side independently of that of the client side. In doing so you're able to do things like turn on chunking or transfer encoding for the servers even if the clients don't support it. This one is straight forward and quite handy, just like I like 'em.

when HTTP_REQUEST {
   set orig_version 11
   if {[HTTP::version] eq "1.0"} {
      set orig_version 10
      HTTP::version "1.1"
   }
}
when HTTP_RESPONSE {
   if {$orig_version == 10} {
      HTTP::version "1.0"
      if {[HTTP::header exists "Transfer-Encoding"]} {
         HTTP::payload unchunk
         HTTP::header remove "Transfer-Encoding"
      }
   }
}

Http Response Based on Requested Uri

http://devcentral.f5.com/wiki/default.aspx/iRules/HttpResponseBasedOnRequestedUri.html

Another great example of simple things you can do with an iRule that can turn out to be extremely useful, this iRule responds to certain HTTP requests. It only does so after parsing the original request, though, so you've got a little more control than just blind responses. This could obviously be expanded to do just about anything you want, but the example given, acting as a pool member for testing, is pretty handy in its own right.

when HTTP_REQUEST {
   set data {Some data or HTML to send to the client.  If you want to use variables in here, replace the curly braces with quotes.}
   if {[string match {/[1-5][0-9][0-9]*} [HTTP::path]]}{
      HTTP::respond [string range [HTTP::path] 1 3] content $data "a_header_name" "a_header_value"
      log local0. "Sending [string range [HTTP::path] 1 3] response with $data"
   } else {
      HTTP::respond 200 content $data "a_header_name" "a_header_value"
      log local0. "Sending default 200 response with $data"
   }
}

Return_default_favicon

http://devcentral.f5.com/wiki/default.aspx/iRules/Return_default_favicon.html

This iRule, which I talked about in one of our previous podcasts, caught my eye as an ingenious little code snippet that could prove quite useful. All it does is perform the simple task of redirecting users to a given favicon.ico file, which may seem mundane. Given some experience as a server admin though, and knowing the different vectors requests come in from, the way different applications point to specific files without telling you, etc., this could prove quite the time-saver when it comes time to update your icon.

when HTTP_REQUEST  {
#Thomas Schaefer, Better Software Solutions, Inc.
# A crazy simple iRule to redirect any favicon.ico requests to the favicon on your homepage
# This promotes a uniform presentation.
# Note this could be expanded to server the data right from the iRule (think external data class)
        if  {[HTTP::path] ends_with "/favicon.ico"}{
                HTTP::redirect "http://www.mycompany.com/favicon.ico"
        }
}

Hopefully you've found some use in these pocket sized rules. I'll keep scouting them out and bringing them up if you'll keep using them. ;)

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Categories: DevCentral , iRules , Ramblings

DevCentral Top5 04/24/2009

Colin Walker — Fri, 24 Apr 2009 20:29:34 GMT

Whether you're looking for the best bits of v10 coverage or how you can make SAP and your F5 devices work together, this week's Top5 has what you need. The v10 content just keeps on coming, with some great additions this week. It's been a busy week and there are also some excellent non-v10 specific things that warrant highlighting, so you'll get a mix of both this week. Getting right to it, here's this week's Top5:

F5 and SAP Integration - Auto configuration and monitoring under BIG-IP v10

http://devcentral.f5.com/weblogs/nojan/archive/2009/04/17/f5-and-sap-integration---auto-configuration-and-monitoring-under.aspx

A welcome post by Nojan gets the ball rolling this week with a great highlight of SAP and F5 working together. This is an integration that's worth noting, as it can likely provide some insight and help on making the heavy lifting required to configure and maintain an SAP portal within your network a breeze. Nojan goes through to highlight a few different ways in which we can, or will soon be able to, help manage your SAP installation, namely: detection, configuration, and monitoring. This one almost hit my marketing filter at first glance, but there's some very decent info in there and interesting screenshots to clarify things even further. Nojan knows his stuff, so take a look to get the details.

v.10 - Working the GTM Command Line Interface

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=356

In the straight-forward, geek talking to geeks style that I've come to know and love from Jason, this article works through configuring some GTM objects via tmsh. He's got some pretty extensive experience dealing with GTM, and it's great to hear about his impressions on this stuff as an authority, and a true techie. He's got graphs, stats dumps, iRules code and command line sequences all in one post..that can never be a bad thing. There's plenty of info here to help get you up to speed quickly with tmsh in your GTM environment, and Jason's style is as effective as always at putting it out there. If you get gleeful for geekery, check this one out for sure.

v.10 - BIG-IP UI Walkthrough

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=357

Joe's taken on the task of walking us through the features of the new dashboard available in v10. He's put together an easy to consume video that shows you what you'll find in this cool new feature in the GUI. The graphs that you've come to expect are still there, but this new set of info gives you a different way to look at what your system is, and has been, doing. From cpu usage to the number of connections, you can watch the real-time charts update as things fluctuate, which can be quite handy for testing or monitoring real-time changes in your app's performance after a roll-out or the like. I had heard about this but hadn't really seen it yet, so this one caught my attention.

What's new in the LocalLB iControl interface

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=355

For all of you iControl lovers out there, Don digs into the new methods available to you in the new LocalLB interface. There are several of them from "set_packet_loss_ignore_rate" to "set_security_enabled_request_state" that offer you all sorts of new options to allow for even more iControl coding goodness. If you've been waiting for new and improved ways to integrate your application with your BIG-IP, then this one is for you. Even if you're still debating the iControl coding route, I'd recommend checking this one out as, to me at least, it's always cool to see what new tools we have available to us.

It's like load balancing. On steroids.

http://devcentral.f5.com/weblogs/macvittie/archive/2009/04/20/itrsquos-like-load-balancing.-on-steroids.aspx

Choosing just one of Lori's blog posts for the Top5 is proving to be a more and more arduous task. This week, her 'roids titled article really stands out in my mind as one that deserves calling out. This post breaks down just what Application Delivery is, which is something that many people still have a hard time fully comprehending. These aren't just load balancers with some fancy marketing around them, these are seriously power-packed systems that perform a huge array of tasks with some highly focused intelligence and a stance leaning towards integration and ease of use and management. The chances that you'll need all of the functions available from the get go are slim, but most people I've seen quickly find out just how much better life can be with an ADC in the mix. Lori explains, in her ever entertaining and readable style, just what these things can do, as well as why you just might need one yourself.

Thanks for tuning in to the Top5 this week. Shoot me your feedback and/or suggestions if you've got them. I'll be back with five more next week.

Technorati Tags: F5,DevCentral,Top5,iRules,SAP,GTM,iControl,ADC,Application Delivery,Colin Walker

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Categories: DC Top5 , DevCentral , Development / General IT Goodness , iControl , iRules , Monitoring/Management , Ramblings , v.10

Slashdot - A double-edged sword of geekery

Colin Walker — Fri, 17 Apr 2009 22:55:04 GMT

Lori's recent Dear Slashdot blog post was not only interesting and entertaining, but it was also very popular. So much so that it got picked up by, and posted on Slashdot. When you're one of the people responsible for the site hosting such a suddenly famous post, this is both fantastic, and a little bit scary.

I'm always happy to see people writing compelling things that will draw attention to the other awesome stuff going on on DevCentral. Lori is fantastic at that, and this recent post is a prime example. By getting pushed out to a major geek news site like /. she's bringing in a huge influx of visitors that would likely have never seen DevCentral otherwise. Some will leave after reading her article, sure, but others will stay. They'll be interested by what she wrote and go digging to see what else is out there. They'll find the killer tech goodness that is DC and maybe they'll stick around. This is the awesome side of Slashdot fame. There is, however, a darker side.

The term "slashdotted" has been simultaneously feared and strived for by many in the tech industry for years. Wikipedia explains what it means:

"The Slashdot effect, also known as slashdotting, is the phenomenon of a popular website linking to a smaller site, causing the smaller site to slow down or even temporarily close due to the increased traffic. The name stems from the huge influx of web traffic that results from the technology news site Slashdot linking to websites. The effect has been associated with other websites or metablogs such as Fark, Drudge Report and Digg, leading to terms such as being Farked or Drudged and the Digg effect. Typically, less robust sites are unable to cope with the huge increase in traffic and become unavailable – common causes are lack of sufficient data bandwidth, servers that fail to cope with the high number of requests, and traffic quotas. Sites that are maintained on shared hosting services often fail when confronted with the Slashdot effect."

I've seen many, many small-ish sites shut down completely for days on end thanks to a good slashdotting. If someone had asked me if I would be concerned about DevCentral going down, or at least having major performance issues, thanks to be slashdotted, I'd be a liar if I said I no. Sure, we have fantastic BIG-IPs and WAMs and other F5 gear in front of the site. We have optimization iRules and all sorts of cool things to keep us up and running. I've seen what these things can do in test, and talked about theoretical limits, and I'm very confident in the infrastructure we're running. Putting all of that to test with a huge traffic spike against the production systems, though? That's always a little un-nerving.

Well, it was yesterday, anyway. Since then, Slashdot picked up Lori's post, and we have indeed seen a huge spike in site traffic. The number of hits has gone up dramatically, we've seen scores of new users coming in, and because of that the application servers trying to serve content for DevCentral have been ... bored. I know. It doesn't add up, right? A huge spike in hits and overall site traffic, a direct Slashdot link and ... nothing. I'm honestly not sure the servers even knew something had happened. Why? Web Accelerator, that's why.

We've semi-recently deployed Web Accelerator in front of DevCentral. The system does all sorts of performance tuning for the site now. It makes things faster in general, as reports from all around the world have confirmed. One very, very key feature though, at least in this case, is caching. Thanks to the powerful, advanced caching features of Web Accelerator (WA), roughly 85% of the traffic during the spiked period of being pummeled from Slashdot was served from the active cache.

That's ... amazing. Sure, I know caching isn't a new technology or anything. I know it's been around for a long time and many people are doing it very well, in many ways. I've read about it, implemented it, coded for it, etc. I'm just saying that to have it make such a hugely profound impact on the servers that I know and love, and to realize that without the WA boxes in front of us our app servers very well may have felt some severe pain, makes it hit a lot closer to home.

As you can see in the graph to the right (generated by WA, by the way), we were experiencing pretty normal site traffic until the Slashdot article hit. Once it did, we saw a very substantial jump in site traffic. To be clear, the green bars in the image are the requests being served out of the cache. The light blue bars above them are new requests to the application servers. Notice that the blue bars didn't grow much at all, even with a gigantic increase in pages being served? Thank you, Web Accelerator, for filtering out the bad side of being slashdotted, and letting us enjoy only the good.

Also, a huge thanks to the IT guys here at F5 that helped us get this solution in place to make things better for the community. It was one of them that pointed out what a great job WA was doing through the traffic spike, and I really appreciate them being so on top of things.

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Categories: DevCentral , Development / General IT Goodness , Monitoring/Management , Ramblings

DevCentral Top5 04/17/2009

Colin Walker — Fri, 17 Apr 2009 21:44:48 GMT

Here we are, weeks after the announcement of BIG-IP v10, and the hits just keep on coming. It's been another busy, exciting week here in DevCentral-ville. There has been plenty going on to keep track of, and then some, so I'll try to distill it down a little, as always. That said, it's a shame to miss any of the great stuff that's coming out, so make sure to check the rest out for yourself. You're not here for all the content, though, just the best…well my Top5 picks, anyway. Here they are:

Dear Slashdot: You get what you pay for

http://devcentral.f5.com/weblogs/macvittie/archive/2009/04/17/dear-slashdot-you-get-what-you-pay-for.aspx

Starting things off with a bang, a zing, and a bullet, is Lori's great post in response to a write-up about SSL acceleration. In the original article, which is worth checking out to understand the context of this post, os3 put together a solution for a showdown with a BIG-IP 6900. Unfortunately for them, they derive a few points that Lori found…questionable. There's no doubt merit to the type of solution they put together, it's just not a fair comparison. Many things are left out of the equation and a realistic, long lived deployment isn't depicted. I won't try and re-cap the whole thing, as Lori does so far better than I could in her post, which you should go read This is also Lori's second appearance for F5 on Slashdot, which the geek in me can't but help call out.

v.10 - BIG-IP UI Walkthrough

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=2312

In this article Joe walks through some of what's new in the re-vamped, improved user interface in version 10. The interface was re-worked pretty heavily for the new version including such things as improved, form-based logins that allow for timeouts and smoother authentication interaction, improved responsiveness for page loads, and context-sensitive help functionality. There are plenty of people that are very excited about these new changes and the way it's going to make using and administering their systems a better experience. Frankly, I'm one of them. Joe provides commentary and screenshots of several key features, which makes for a great read.

v.10 - Testing Configurations

http://devcentral.f5.com/weblogs/dmacvittie/archive/2009/04/16/v.10-ndash-testing-configurations.aspx

Putting several of the other irons in the blogging fire on ice, as it were, Don digs into the ways in which you can use both the new LVM and Evaluation Licensing features to achieve some pretty fantastic testing scenarios on your BIG-IP. Each of these functions are cool, in and of themselves but, as Don points out, when used together they can make for some pretty hawesome scenarios. I'll spare you some of the hardcore geekery that comes to mind here, I.E. booting from one partition to the next at will for varied testing, VM like functionality with cloned partitions storing slight variations of configs…hmm, maybe I won't spare you. Regardless, this is a great post that's backed, again pointed out by Don, with some really fantastic work done by not only the Developers to make it happen, but the folks writing about what it can do. That combination makes for a killer feature that not only works, but one that's usable and interesting, since people can grok it with ease.

v.10 - A Look at Route Domains

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=353

Not to be left out of the v10 fray, Jason puts out another fantastic, deep tech article on Route Domains. A feature that's new for v10, route domains basically allow the re-use of IP space within your BIG-IP. This is something that's been asked for or at least about several times, and Jason dives deep enough to get those propellers spinning, which is something I can always count on him for. It's great to see him dig right into what can be done, testing TMM to the creation limit (creating 4094 route domains just to see if it breaks), and using the tmsh shell while doing so. I love it when I walk away from something on DevCentral saying - "Wow, that's super useful…" and that was definitely the case here. With an easy to follow, step-by-step walkthrough, Jason takes you from 0-60 on route domains with ease.

v.10 - iRules and the after command

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=348

As a true departure from the topics you'll normally find me writing about, this week I chose to write about … iRules. I know, you're shocked. I'll give you a moment to recover. Now then, the after command was added in BIG-IP v10, and I'm pretty stoked about it. The ability to inherently induce a specified delay period before executing code is a very powerful scripting tool that has been missed by many in their iRuling efforts thus far. The fact that we can now do so is geektastic. Being able to use the -periodic flag to repeat the evaluation of a given code block on a timer as well…that’s just icing on an already tasty geek cake. I'm just digging in myself to see what kinds of things can be done with this command, and frankly I'm pretty darn excited by the possibilities in v10 as a whole, which this is a part of. While I'm not trying to say this one command is going to help you take over the world, it certainly can't hurt.

I think every week I have more fun picking and highlighting the items in the Top5. That is almost solely due to the continued and escalating excellence of the content I get to choose from. More and more of the stuff we've been putting out has roots deep within different departments inside F5, not just DevCentral (we're just the messengers on lots of it) and I have to say it's awesome to get to write about all of it. So far all of those contributing, a hearty thanks. Also - I want to give a big thanks to the iRules-SME group as well, as they're continually giving me great ideas and inspiration to keep pushing the ball … err … rules.

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Categories: DC Top5 , DevCentral , Development / General IT Goodness , iRules , Ramblings , v.10

iRulesTips tweet roundup

Colin Walker — Wed, 15 Apr 2009 16:54:37 GMT

A couple weeks ago I started sending out tips for iRules users via twitter. I created a hashtag: #iRulesTips and I've been passing out tidbits of iRules advice / info on a pretty regular basis. The goal is to post something daily (or a couple times a day) but with the way things are going around here (see: super busy), I'm happy with "almost daily". Jason even saw fit to chime in with his own contribution, which is awesome. I'm hoping more people will add their own tips, tricks and advice as they see fit.

Here's a roundup of the tips that have been sent out so far:

#iRulesTips - [string match "/*/index.html"] is likely greedier than you think. It's not going to limit things to a single layer of dirs.

#iRulesTips - list statements passed to string map rock. Something like [string map [list $find $replace] $data]

#iRulesTips - Know your event context. My recent doc made me think of this. Some commands behave differently for client vs. server context

#iRulesTips - HTTP::host and other such commands are references to a memory location, not queries. They're less overhead than variables.

#iRulesTips - This STREAM:: commands make the already hawesome stream profile infinitely more flexible. Way preferred to manual replacement (Yes, that should have been "the", not "this")

#iRulesTips - the GTM whereis command options country & continent return both in a list prior to v10. Use lindex to extract each. (From citizen_elah)

#iRulesTips - You can log directly to a remote log server via UDP by using - log <IP>[:port] <facility>[.<level>] <message>

#iRulesTips - Using iRules with the stream profile is amazingly powerful. Custom sub strings, toggling replacement, etc. take good to great.

#iRulesTips - new in v.10! The new after command rocks socks. Check it out: after <ms> <script to execute>. -periodic lets it repeat

#iRulesTips - In v10 the static namespace makes static globals better. Try static::<yourVar> instead of $::yourVar (static variables only)

While it hasn't quite been every day, it's been pretty close, as you can see. Hopefully folks are finding these handy. If nothing else, it's great for me to keep things top of mind, short and sweet, and keep dolling out iRules goodness in different ways. Follow me on twitter (colin_walker) or search for the hashtag (#iRulesTips) to see these as they come out.

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Categories: DevCentral , iRules , Ramblings

DevCentral Top5 04/10/2009

Colin Walker — Fri, 10 Apr 2009 18:56:55 GMT

It's an interesting relation that the more awesome, noteworthy content there is on DevCentral in a given week, the harder it is for me to narrow down what it is I want to call out in the Top5. That being said, this week is easily the toughest week to decide what to highlight in recent memory. With the BIG-IP v10 announcement dropping and the ensuing flood of killer content, there is an over abundance of options. That's a wonderful "problem" to have, though. I want to say this week especially that there are many killer things that are worth a look out there on DevCentral that didn't make the list, so go check them out. As always though, here I am, sifting through all of that goodness the best I can to bring you my favorites. Here's your Top5:

The Revolution Begins: Arming the Data Center

http://devcentral.f5.com/weblogs/macvittie/archive/2009/04/08/the-revolution-begins-arming-the-data-center.aspx

Leading the charge, both literally in terms of content for the day, and figuratively in terms of her message, is Lori MacVittie. This absolutely fantastic blog post is part of her recent series talking about independence in the data center. It's a must read as it not only calls out some of the killer new features in v10, in an easily consumable fashion, but it also goes through your rights in the DataCenter. This clever way of delivering a strong message had me raring to go as we launched into the launch day festivities. Read it, pin it up on your wall, recite it before bed, I don't care. Just make sure to take a look. This one is #1 for a reason.

v10 Introduction to the tmsh Command Shell

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=347

One of the changes most interesting to me in v10 is the complete revamp of the way you can interact with the system via the command line. No longer are you tethered only to the bigpipe command. Now there is a far more elegant and usable interface available to you by way of tmsh, the new command shell on v10 systems. Bigpipe is still there for legacy purposes and to give people time to get comfortable in the new, bold world of tmsh, but as Don alludes to in this article, I'm relatively confident that once people start using the new interface they'll quickly adopt it full time. Take a look here to see what it can do, and find out where you can learn more.

v10: GTM, Meet CLI

http://devcentral.f5.com/weblogs/jason/archive/2009/04/09/v.10-gtm-meet-cli.aspx

Continuing on the theme of new and improved interfaces for v10, Jason delves into the new command line interface now gracing GTM as of the new release. His exuberance will be shared by many as they get the chance to dig in and manipulate their GTM properties in new and powerful ways. He also goes on to spoil his own Tech Tip a bit by summarizing the cool iRules changes for GTM in v10. So much content you can barely talk about iRules? Isn't that blasphemy of some sort? GTM is a stellar product and I'm very happy to call out these cool changes.

v10 - New class features in iRules

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=2309

Speaking of iRules, there are lots of awesome new things in v10 for my fellow iRuling brethren. Amongst them are the killer new after command, SSL data inspection, and the restructuring of data groups to be much more powerful and usable than before. To make use of all the goodness squeezed into the new classes, there's a special new class command added in v10. This doc is your guide to what it can do, how it works, and some examples of the powerful new things that can be done in your iRules. It was enough to get me even more raring to go than normal to code some iRules, and that's saying something. You can also check out all the new iRules (and iControl) commands in their respective Wikis on DevCentral. Read. Code. Rejoice.

v10 Try Before You Buy

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=2307

Last but certainly not least is Jeff's article about the fantastic new Evaluation Licensing features in v10. Have you ever wanted to try a new module but couldn't justify allocating an entire new box to testing? Wanted to add a module to an existing LTM to test but were concerned that you'd have to re-license the entire thing? Apparently we were listening to your concerns, because in v10 the licensing system was completely overhauled and it's pretty darn impressive. Now you have far more control and flexibility in how you manage, deploy and license the modules on your systems. I have to say that for a feature that isn't purely geek and hardcore tech, this one had me pretty darn excited. This is a huge step forward in the way we handle these things, and everyone needs to hear about it.

Phew, I made it! For a while there I was sure this would turn into the Top10 or Top15 with all the cool things to talk about. Maybe I'll save a few for next week and toss them out to you then. For now though, thanks for reading and please feel free to fire off any feedback or suggestions.

Technorati Tags: F5,DevCentral,v10,iRules,iControl,TMSH,GTM,Licensing,Data Center Rights,Top5,Colin Walker

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Categories: DC Top5 , DevCentral , Development / General IT Goodness , iRules , Ramblings , v.10