www.nico.schottelius.org/blog/what-is-configuration-management.mdwn

[[!meta title="What is configuration management?"]]

As I'm currently thinking about writing a configuration management tool,
I'm sitting in the train and philosophise about 
the general question: ***What is configuration management (CM)?***

## View 1: The System

Let's imagine I am a computer system.
What happens to me, if I am put under version control?
Somebody (**a process**) which is running on me, changes
stuff on me, so that she (the process) is happy afterwards.

I recognise that some files are added, changed or deleted.
Some processes are being run, some killed.

That's probably it, because I don't own anything else she
can change.

## View 2: The Sysadmin

I'm one of those guys, who are told to do world domination,
but got bored. I'm a sysadmin. I am very, very lazy.

I installed a lot of systems, just for fun.
Now somebody (probably even a user!) tells me, he wants
something to be changed, because he wants to actually
use the system (pretty awkward idea, but heard about
those situations).

As my boss told me that we cannot exist without users,
I even consider doing the change, though I'm afraid:

 * What happens if the user requests more changes?
 * What if the machine crashes?
 * What if another sysadmin needs to add changes?
 * What if two systems should look very identical, though not completely?

This leads to some easy objectives:

 * CM must be easy to read and understand, so I can understand tomorrow what I did today.
 * CM must be able to redo the work
 * CM must provide a way to have multiple commiters
 * Having a way to reuse already defined stuff is helpful

Oh, there's another interesting point:
To be able to communicate with a user and to understand him,
it would be very helpful, if I can tell my CM **this is what
the user wants** instead of **do x, y and z**, which neither
the user understand, nor do I know why I did it.


## View 3: The manager

Yes, it can get even worse, there may be managers or bosses
around, who pay the poor sysadmin. The sysadmin claims to do
her best job, but as a manager, I don't understand what she's
doing. Nor do I really care. I care about the users
(which could be customers as well!) and that their demands.
And about how many users and how many demands my sysadmin
fulfilled. And I want fancy graphics, 24 bit coloured pie
charts in 3D and whatever comes to my crazy manager mind.
And numbers. Many numbers.

## View 4: Merging the views

Assuming these are the players in my first round of CM
brainstorming, there are some outcomes:

 * CM must be easy to use, so the lazy sysadmin will use it
 * CM includes ideas from users
 * The configuration management is maintained by the sysadmin
 * Your managers are happy, if the CM outputs "manager readable data"

## More stuff

I'll add more ideas about CM here soon. If you (dis|)agree with me,
just [let me know|about] so I can include your critics in the next article.

[[!tag config eth unix]]