Once, a group of friends and I were standing in the data center of a large Fortune 500 company, and one of us was bragging about his new server with “hot-swappable” disk drives. Keep in mind, this was new technology back then, so he was really rubbing it in our faces. “You could pull out any one of these drives, and plug in a new one, without shutting down the server!“ he said.
“Do it, then“ one of us said, with a smirk.
He looked at us knowing what it was he had to do. Personally, I really don't know why he actually did it, just to save face, I think, maybe to show off, I'm not sure, but what happened next was the funny thing.
As soon as he pulled out one of these hot-swappable drives, the entire server went down. I think it even made that big “Zewerererewwww” sound as it crashed. He spent the next day and a half re-building the server, and cursing us for rolling around on the floor laughing.
Which brings me to yesterday afternoon.
See, some months back I developed and deployed an small Winforms application, using the Updater Application Block for updates. I even blogged about how to do it. I tested this on a bunch of XP and 2003 machines here. It worked great. I was so proud. I kept telling everyone, “You know, I could deploy out a new version, and all the clients will update automatically!“ I said this a lot.
I needed to deploy some minor UI changes, so yesterday, I pushed out the new version to our server, and checked a machine that is setup like the one client that's currently using it, to see if the app would auto-update. If everything worked, I should have seen a dialog box alerting me to the new version.
Nothing happened. It just didn't work.
UPDATE: It did in fact work, just not from my Terminal Services login! Turns out that BITS doesn't work under terminal services for Windows 2000!
The reason why this failed has to do with Windows 2000 Server and BITS, and some other fairly complicated to debug things. I haven't found a solution, but when I do, I'll certainly post about it. It all isn't a big deal since there's only one client currently using this application. I can just email them the updates. But, how embarrassing. Since I blogged about it before, I just wanted to warn everyone, that if you use the UpdaterBlock, with the BITS downloader, it may not work under W2K.
That's the big problem with these rarely needed processes. By their nature, they're rarely tested in the real world and usually pretty important. They're used so infrequently, that no one really knows if they'll work when they actually need them. I recently heard about a company who's entire disaster recovery strategy depends on a pile full of tape backups which they've never tested. Good luck to them. In this way, the entire pattern of the AppUpdater block is flawed.
I can't wait for ClickOnce.
-Brendan