Last year I wrote a script that I have installed for my current client that parses a router configuration archive in order to create a database of IPs configured in the network (I’ll write a post with more detail about what that tool does some time, as I’m curious to see whether it’s something that other people would find useful). I wanted a tool that didn’t reinvent the wheel, and since I had a readily available folder containing all the device configurations, I used what was already there rather than having to build my own tools to extract the configurations as well, or hook into one of the configuration management products.
In maintaining and improving that tool, I’ve stumbled over a number of interesting issues that have led me to think there has to be a better way. And I guarantee I’m not the first person to be thinking this…!
As a consultant, I have had the pleasure of working for a large number of companies in a range of industries, and one of the things that interests me in all of them is seeing the varied approaches to network changes, from the initial determination of what change needs to be made, following the change through some kind of Change Control process (in most cases), through to execution on the production network. The one thing that’s consistent with every company is that they aren’t consistent – they all have their own way of doing things, and while there’s some fundamental commonality between them, each is usually missing steps that I would consider important.
I’m not going to try to document a full change control process here (though of course, if you want to engage me to consult for your company, we can discuss that), but instead I present to you:
The Network Engineer’s Guide to Making Changes
A common sense approach to making supportable and repeatable changes to your network.
I’ll bet that at one time or other in your life, you’ve had your name written in your clothes. You know what I’m talking about – either you buy some specially made labels to stick in your clothing, or you use one of those laundry markers to scrawl it on the care label. Usually this is exclusive to children’s clothing, as perhaps they are most likely to leave their clothing lying around for somebody else to find; if their name is in it, the finder can clearly identify who the item belongs to and everybody will be happy, especially Mom and Pop who paid for the thing.
As adults however, it seems most of us don’t label our clothes – we assume that we are too clever to lose anything, so we become careless about labeling it. In reality, writing your name in your clothes takes seconds and may save you down the line, so it’s kind of stupid not to.
I know what you’re thinking – what on earth does this have to do with networking? Let me explain…