I'm a system administrator. This is a rather broad term. It involves work on everything between "architect", "teacher", "analyst" and "janitor" in the context of information technology.
For my day-to-day work, I use puppet a lot. It automates all the boring parts of my job, and lets me spend time on the interesting parts.
I'm also quite involved in service monitoring. Anything that can observe my systems over a period of time, and give me alerts and pretty graphs is a good thing.
Once upon a time, I wrote a bunch of pages on free software system administration. While most of them are not being updated, they may still be useful.
Some of these are more true than others, at different times, of
course... All of them describe my job. 
Don't tell my momma I'm a sysadmin, she thinks I play piano in a whorehouse.
Alan J Rosenthal, ASR
Confidence is the feeling you have before you understand the situation
unknown
If that makes any sense to you, you have a big problem
C. Durance, Computer Science 234
Never attribute to malice that which is adequately explained by stupidity
Hanlon's Razor
Any sufficiently advanced stupidity is indistinguishable from malice
me