Something happened at home today that reminded me of something I used to do when I worked at Bell Labs.
My rule was simple. If a machine in the computer room wasn't labeled, I was allowed to power it off. No warning. Click. No power.
If I logged into a machine as root and the prompt didn't include the hostname, the only command I was interested in typing was "halt".
Both of these rules came from the same source: If sloppy system administration was going to lead to errors and downtime, I wanted that downtime to happen during the day when we can fix it instead of late at night when we should be asleep.
(Of course, if a machine didn't have the hostname in its root prompt that also meant our configuration management system wasn't running on the machine which is a security violation. Therefore halting the machine, as far as I was concerned, was solving a security issue. But I digress...)
When I would explain this rule to people often they would ask, "Would you do that even if it was an important machine?"
"Ah ha!", I would exclaim, "My definition of 'important machine' includes that it is properly labeled! You see, if something is important we take good care of it. We protect it. One way we do that is to label it front, back, and in the root prompt."
Sometimes I would get a look of horror.
I never actually had to turn off a machine. I presume that if I did the owner would have come running soon after. I'd say something like, "Thank god your here! I was able to make a label for this machine and I need to ask you what its name is!" If they asked, "How did you know It was my machine?" I would have said, "Well, once it is labeled I'll be able to send email to the owner and ask!"
I did once threaten to power off a machine. It was a new machine and someone was standing there loading the operating system. "Hey! No fair! This machine was brand new! I was going to label it!"
"Amazingly enough", I pointed out, "machines can be labeled before you load the OS too."
[I wouldn't let him type until the machine was labeled.]
Labels are a very basic safety precaution. It prevents human error.
Labeling machines is obvious, or is it? I visit other people's data centers (or "computer closets") and find tons of unlabeled equipment. "It's ok, I know which machine is which." they say. That's just an accident waiting to happen! Without properly labeled machines it is just too easy to accidentally power off the wrong machine, disconnect the wrong cable, and so on.
Isn't this simple professionalism?
You don't label things for Today You. Today You is smart, knows what's going on, and got good night's rest. You label things for Tomorrow You plus Other People. Tomorrow You may be related to Today You but I assure you they are different people. Tomorrow You didn't get a good night's sleep. Tomorrow You was away for a few weeks and now can't believe how similar all those machines look. Tomorrow You left for a better job and is now someone else trying to figure out what the fark is going on.
Other People need labels on machines for all the obvious reasons so I won't bore you. However when I visit other people's computers rooms (and I do get invited on many tours) they often say that the lack of labels is OK because "they're a solo sysadmin." Let's debunk that right now. Nobody is totally solo. When you call into the office from 3,000 miles away and ask the secretary, office manager, janitor, or CEO to go into the computer room to powercycle a machine, you are no longer a solo sysadmin. Things must be labeled.
In my time management classes I talk about delegating work to other people. Usually someone laughs. "Delegate? What planet are you on? I can't delegate anything!" Of course you can't if you haven't labeled things.
I prefer to write about big networks, big data centers, and big sysadmin teams. To them, all of the above is obvious. It's a waste of time to write this, right? Sadly something happened to me in my non-work life that reminded me about my "no label, no power" rule.
To be honest I haven't touched actual server hardware in years. All my servers are in remote data centers, often in countries I've never been to, with highly skilled datacenter techs doing all the physical work. I've never seen or touched them.
However if I were to change jobs and found myself dealing with hardware and small computer rooms again the first thing I will do is put a big sign on the wall that says:
"This computer room is for important computers only. Important computers are labeled front and back. Unimportant computers will be powered off with no warning. -The Management"
Isn't that reasonable?
Does the service tag count as a label? (Assuming you can tag the service tag to a group/user/entity through your host management database.)
This doesn't change, while the hostname might change.