services monitoring, flap detection and mail flooding

There are features in software which you learn to estimate just the very moment you understand why they are there. By now, running nagios internally for monitoring the availability of server hardware and processes, we used to have disabled a feature named flap detection which, to cut things short, does “recognize” whenever a service seems to change its state too quickly (in other words, is “flapping”). What’s the point? A while ago, we disabled flap detection in course of integrating nagios in our environment after we missed some messages of services being left in “flapping” state, so we decided to rather be notified in case a service goes down or comes up.

Why is this a bad idea? See, and especially have a look at the Date column in my inbox this morning:

This is a pretty good example of what flapping practically is – a pretty good way to fill up your mailbox, or, worse, the text message store of your cell phone. So, let’s have a look at how to set flap detection right.

a better mouse trap #1: persistence, document storage and couchdb

Ever considered building a better mouse trap? Well. I do, actually, each and every day anew. I will leave out most of the more in-depth considerations related to this, as for now they don’t matter – the only thing worth knowing, initially, is that the process of “migrating”, “updating”, “rebuilding”, … an existing, fairly complex application system is something that is painful beyond all imagination, and this even while “just” considering the mere technical effects and aspects of this procedure…

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digging into the Palm Pre…

After being with my K800i for more than three years, indeed I wonder why actually get a new cell phone, why bother dealing with syncing contacts, configurations, … between two devices again? Well, while being a good, reliable, stable device, there are some things about the K800i that have come to bother me, recently, and subsequently are the features I’d like to see in a successor. Some of them, in no particular order:

  • The e-mail functionality that comes with the K800i is next to unusable. Most of the mails I tried to read didn’t get rendered correctly due to “unsupported character set” which seems a known problem / limitation of this device. To compensate for that, I’ve been using the open source, Java ME based mujmail for a while, which worked more or less stable but is in no whatsoever way integrated with the rest of the cell phone, so neither you can open embedded HTTP links in the K800i browser, nor you can dial any phone number right out of an e-mail rendered in mujmail. There are ways to compensate for that, but it’s sort of annoying.
  • More than just once or twice, the last couple of weeks, I felt the ability to open PDF e-mail attachments a feature rather useful even for a mobile device. Been searching for some tool to fill this gap for quite a while, but failed to find a feasible Java ME / native K800i PDF renderer…
  • While being decently fast, the K800i embedded browser is pretty limited in terms of functionality, especially when it comes to displaying some sites I regularly use ( There, too, aren’t really any options how to improve this situation.
  • The K800i doesn’t know about WLAN, which is painful as once in a while I end up being in a situation in which there’s no cell link and some sort of wireless LAN is the only way to connect with any piece of the world, and be that textual / for the purpose of sending and reading mails.
  • Using my Internet Pack M, I then and now used Google Maps for navigation purposes, which however proved difficult as the K800i is not capable of recieving GPS signals, so you basically have no location-based services at hand.
  • Doing remote access to our servers, so far I used K800i + dial-up + netbook, mostly for small operations (restarting a service, looking at some log file, …). Though this works rather well, it always requires you to have two devices at hand, two devices sufficiently charged, and you need a, though fairly small, place to operate the both of these devices. For most operations, simply having an SSH client installed on the cell phone will perfectly do, so I was looking for a phone to allow for doing right this, as well.

After comparing a few devices, also (of course) taking monetary aspects into consideration, I ended up ordering a Palm Pre, which is distributed by o2 in Germany exclusively it seems, recieved it the very next day (wow, that’s fast…), and by now already spent a few days with the device, learnt a couple of things, played around a lot, did come to some preliminary conclusions…

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C# and mono: getting some feet wet…

Well, some of the readers of these pages will have noticed that, carefully speaking, my enthusiasm for Microsoft technology is pretty limited. “Limited” indeed is the right way of putting it: While I have a clear opinion about most of Microsofts monopoly regarding desktop and office software (which, in the end, makes me avoid both as good as I can, and thanks at the very least to Ubuntu GNU/Linux, right now I can do that pretty well… ;) ), I then and now always considered Microsoft .NET, as a development and runtime platform, a pretty good thing, maybe the best technology the Redmond folks came up with to date, and definitely a technology that could have offer wholly new options to both Microsoft and the rest of the world if licensed and distributed a little more openly. Anyway, leaving licensing and personal considerations related to this aspect aside: These days I earn a living mainly off working with Java and overally am pleased with this as an environment. However, as “integration” is what I mostly deal with, I finally had the chance of dealing with Microsoft .NET and C#, and had a rather pleasant trip…

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UI tooling and beyond in NetBeans and Eclipse(4)

Whoever is reading this weblog more or less regularly will have noticed that I am an enthusiastic user of NetBeans for most of my development needs, and this holds true even now that, given a current project of ours, I have to switch IDE at least once daily, as we do a project based on Eclipse Rich Ajax Platform and NetBeans, as comes as no surprise, is not too good a tool for building applications which are more or less built atop the Eclipse RCP core (well, getting deeper into things and especially talking about RAP application deployment, you’ll figure out that Eclipse itself also leaves a lot to be desired here, but that eventually is another story).

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