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License Manager Hell is a term which can only truly be understood by a system administrator who has been to it. You know it when you see it, and you never forget it. It tends to provide a sobering reminder that a state machine with enough variables is, for all intents and purposes, not deterministic.

It is a state of confusion that is caused by the existance of License Managers like FlexLM. It is a particularly bad state of confusion. Let us take FlexLM as an example, as it has been a major player in my personal version of License Manager Hell.

FlexLM is a product put out by a single company. They sell it to lots of other companies. These other companies often get source code for FlexLM, and then distribute FlexLM with their products and give out FlexLM licence keys.

What this leads to is multiple pieces of software, all shipping with multiple versions of the same licence manager. Often new licence keys will not work with older versions of the Licence Manager. This is made even worse, because not all versions of the licence manager are completely equivalent - remember - most of the individual software developers have the source code to the licence manager.

Should you ask for help on these problems, you will often find that the Software Engineers intended that the software be run on dedicated workstations, and not on shared systems. Thus they leave you to figure it out on your own.

Commonly the situation is fixed by changes that make little or no sense. Often the order in which the license managers are run, or that licenses are loaded will matter, or the particular versions used.

Getting out of this hell is usually only temporary. It means rebuilding the House of cards and walking away, and hoping that you're not the next one to knock it over again.

In addition to the above-mentioned problems with FlexLM we run three "redundant license servers". You'd think this would increase reliability, but it doesn't. The first time you discover this is when all three can't talk to each other. They get the brilliant idea that each should become a "master" server. When the network comes back up nobody is willing to become a "slave" server again (which pretty much mirrors human life), so your licenses don't work because you need at least one master and one slave for them to work.

Mention this to the creator of FlexLM (as we did, several times, in frustration) and its falling upon deaf ears. The only solution is to take down two of the servers then bring them back up again. Where's the increased reliability in that? Oh, I almost forgot: the network connectivity usually breaks during weekends and off-hours, so you have the machines page you when this happens. Live close by or learn to remote login and reboot machines.

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