Most data center operators require all their servers to have static IP addresses (or they pin a dynamic address to a specific hardware address, which is essentially the same thing), and most also require them to have meaningful names. This makes a lot of sense for a number of reasons.

First of all, you don’t want someone to be able to come along and plug in any old device into your data center network. After all, this is the pipe that’s most likely to be pumping sensitive information between databases, mainframes, and web servers. By requiring a static IP or a whitelisted MAC address, you make it less likely (but not nearly impossible) for a rogue device to be able to access all the network configuration it needs.

Second, it’s important that consumers of data center services always know how to connect to those services. Granted, this is becoming less important today as these services are more likely to be clustered and hidden behind switches. But a good data center operator always wants to know how to get directly to any of her boxes from a secure shell.

Third, speaking of secure shells, if a server ever does change its IP address or other aspects of its identity, you’ll get an annoying but serious error message.

I’m sure there are many other reasons. And I hope some of my readers will share them with me.

The new thing is that resources in the dynamic data center can be created, provisioned, deprovisioned, and destroyed with no intervention from an operator; old policies about naming and addressing no longer apply. In the dynamic data center, virtual machines appear, do some work, and disappear on the fly. Depending on the virtualization system, a new VM may be assigned a random MAC address just before being loaded for the first time. There is no opportunity for an operator to assign a static IP address to a virtual machine or to configure a newly-created virtual MAC address in a DHCP whitelist.

Data center operators are going to need to change their view of the world. Systems management software vendors need to propose a better way.