This post is another in the series about Configuration Management for beginners.
I’ve posted previously about Asset and Configuration Management, compared some of the differences between the two and the challenges that you face if doing either. This post will extend that by examining how you can make a start on your Configuration Management Data Base (CMDB).
Before you start entering data and creating the CMDB, you need to get a feel for the project with a bit of forward planning. What you need to do is understand what level of detail you are going to go to, what data is going to be stored directly in a tool like Serio and what is going to be linked to, what a CI actually is, and so on.
This is how I would go about it – I’d avoid generalities and concentrate on specifics. Pick a system or service (ideally modest in scale) and on paper try to identify what the Configuration Items are that combine to deliver that system. I’d probably ignore desktops for the time being, and simply focus on the enterprise level components. If you find the task of identifying the Items difficult, consider only those things you wish to subject to Change Control.
You’ll come across lots of little micro decisions to be made. For example, you might find a network device like a router. Taking the case of the one I have sitting next to my desk, it has 3 interfaces – one of which is a BNC-type connector, the other 2 RJ45. Each of these has a specific routing table, and a specific IP address. So how to you represent this in the CMDB? You could:
- Represent it as a simple ‘black-box’ Configuration Item, and just say it routes network traffic?
- Represent it as 3 CIs (one for each interface) linked to a ‘main’ CI that represents the router service?
- Use a simple single CI, but embellish the CI. For example, a Serio user might create Item Attributes to store information about the 3 interfaces.
- Choose to store all of the information about how the router is configured in the CMDB. In Serio you might create a custom data field, or you might choose to link a document.
- Decide none of the above works for you, and miss the router altogether (though I would suggest this is unlikely).
Finding solutions to problems like this will help you understand the right approach for you. Working with a specific system will give you experience, and working on paper (in the first instance) stop you being distracted by any issues arising from your tool or lack of experience with your CMDB tool.
Then take your first draft CMDB, and use it to create a guide for yourself – indicating what data is to be included, the level of detail and so on. It will help you to create a consistent, useful Configuration Management Data Base.
I'll follow this up on Thursday with a post about some specifics of the Serio CMDB.