Zombie scripts and procedures are part of life in IT, no matter how much we try to minimize them. They'll pop up from time to time, surfacing when a partition on a disk mysteriously fills to the brim with logging output or, alternately, with files created hourly or daily that had no reaper process to constrain them. They'll cause spurious network traffic within or without a network segment, causing blips on monitoring graphs that can't easily be explained. If they were poorly written (not unusual at all), they will have little or no error checking and cause huge problems when a server is upgraded or when the behavior of binaries changes enough for them to cause damage, such as when using now-deprecated commands to perform tasks that can choke a server.
But IT zombies are in many ways the opposite of "real" zombies. Those zombies are easy to find and relatively hard to dispatch (well, depending on the zombie movie you're watching). IT zombies are generally hard to find, but relatively easy to disable. The fact of the matter is that the only protection we have against IT zombies is to remember that they exist, lurking in cronjobs and scheduled tasks anywhere and everywhere, ready to cause mayhem when just the right set of bits is flipped.
When an IT problem quickly turns from inexplicable toward impossible, it behooves the erstwhile troubleshooter to remember that these creatures exist, and it might be time to grab a crossbow and go on a zombie hunt.
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