Treat things like cattle, not pets
The "Pets vs Cattle" idea, created by Randy Bias, suggests that infrastructure should be disposable. Servers and other infrastructure can be viewed as either "pets" or "cattle", with pets being unique and indispensable that are manually created, managed and cared for - which is bad. In contrast to cattle which are automatically built, designed for failure, and dispensable - which is good.
In the old way of doing things, we treat our servers like pets, for example Bob the mail server. If Bob goes down, it’s all hands on deck. The CEO can’t get his email and it’s the end of the world. In the new way, servers are numbered, like cattle in a herd. For example, www001 to www100. When one server goes down, it’s taken out back, shot, and replaced on the line. - Randy Bias
Read more from Randy: http://cloudscaling.com/blog/cloud-computing/the-history-of-pets-vs-cattle/