As rare as the Hippocampus and as fleeting as the Pegasus, this special Monday edition of the Top5 is brought to you by "too much to get done on Friday"(tm). Think of it as a bonus edition though, not delayed, as this Top5 comes bearing wondrous gifts from around DevCentral. From iRules Challenges to MVP contributed Tech Tips to a special 20LoL and more, the community has borne deliciously geeky fruit of all manner the past weeks. So much so in fact that the bounty could not possibly be contained within this abbreviated format. Even still, I feel that the five I've chosen are worthy, and I hope you enjoy this week's Top 5:
iRules Challenge #4 Results: Contemplating Context
Every time I get the joy of participating in one of these FSE iRules Challenges I have a blast, but I'm also repeatedly blown away by the abilities of these new recruits. Not only are these people new to F5, but many have no scripting background whatsoever. If that weren't enough, while here in boot camp they're receiving a massive amount of information to process and imbibe every day. Given only their spare time to work on the iRule for the challenge, it's impressive that they even complete an iRule. Despite all of that, however, they somehow persevere and submit awesome entries, every time. This particular challenge was a doozy from the "What the heck did he just ask us to do?" stand point. A brief 20 minutes of questions goes by pretty fast when they're trying to formulate a plan and figure out what the heck they need to know. In spite of the intentionally confusing challenge some strong results cropped up, and I'm looking forward to the next challenge. Well played, one and all.
BIG-IP and Merge File Configuration Changes
Whenever a DevCentral MVP steps up to the plate, watch the fences for the outcome. Michael Yates continued the trend of awesome MVP contributions with his Tech Tip detailing how to make use of the a Merge File to make non disruptive changes to your BIG-IP's config. In a high throughput environment where downtime isn't an option, sometimes even largely simple changes can be a no-go if they cause even a brief hiccup in traffic while the config re-loads. With a merge file you can avoid that interruption, assuming the change itself doesn't cause one (I.E. things like removing a pool or pool member will always cause an interruption, even with a merge file). I get the feeling that this handy technique is something that many other users will be able to benefit from, in part thanks to the solid document Michael has put together to educate future BIG-IP experts. MVP indeed, well earned Michael and thanks for the contribution.
BIG-IP APM-Customized Logon Page
While APM offers some impressive power and inspection capabilities, let's be honest about the default login page: it's basic. Not bad basic, mind you, just simple and functional basic without a lot of bells and whistles that you don't need anyway. Why don't you need them? I'm glad you asked. You don't need our bells and whistles on your APM default login page because it is designed with the concept in mind that you will be adding your very own bells, whistles and any other doo-dads you see fit via customization. The login page is completely under your control. Whether you want to statically alter it, do away with it or like in Jason's fine example here, set up some automation around the way that it's customized via iRules fu, the choice is yours. In this example Jason is displaying how you can combine APM configuration options with a little iRules know how to get a powerful, dynamic result. Take a look for yourself for the details.
F5 Friday: Performance, Throughput and DPS
Lori found a topic last week for her F5 Friday post that resonated so clearly with me that it would have been beyond the power of my will to refrain from adding it here today: DPS vs. Performance vs. Throughput. Now I admit that as a reformed WoW aficionado when I first saw DPS I was confused as to how it was applicable here, but the DPS of which Lori speaks is in fact Decisions Per Second. When dealing with metrics in an application world, how much do you really want to measure network throughput or the number of TCP transactions the network was able to set up and tear down in a given time period? These things are not directly applicable to the application, the way it behaves, what portion of the application's decision making chores have been offloaded to the network in one way or another, etc. What you really want to know, or likely should if you don't, is how many decisions per second are occurring and where. Just how much heavy lifting - application lifting that is - is your network really doing? If you aren't sure, maybe you should be. This is a great topic for discussion, though I warn that it may grow heated as you involve the different groups necessary to gauge this slippery concept. I'm not saying that throughput or TPS or whatever other metrics you're used to looking at are bad or shouldn't be reported, that would be asinine. I'm merely saying, thanks to Lori's unintentional prodding, that you should probably start looking at DPS as well to see where the real work is being done, and how to best tweak that. This one is worth a read for sure to get more depth.
20 Lines or Less #50: iRules Challenge Round-up
Last on the page but first in my heart, I bring to you the (marginally) momentous 50th installment of the 20 Lines or Less series. This series has been running for 3+ years now, and I enjoy it every single time I get to take the time to write it. It's a pleasure sharing the awesome code snippets produced by the community, our engineers, the DC team and sometimes even by me. With over 150 examples of how iRules can provide serious power in under 21 lines of code, clearly no one could refute the benefit iRules bring to the table if they would but take a few minutes to browse through this series and see the proverbial rabbits being pulled out of hats by F5 users worldwide. For this 50th edition I shared my solutions to three of the iRules Challenges that have been issued so far. 50 down and I'm just getting started, so stay tuned for many more, and thanks for reading.
That'll do it for this (last) week's DC Top5. As always thanks for playing and let me know if you've got any feedback, questions or contributions. Until then...