The DML is really nothing more than a software library. Ideally, this should be tied directly into your element management system so that you can define the baseline software image, deploy the image out to the appropriate devices, and audit the network to ensure that all of the devices are inline with your golden software definitions.
As I laid out in the last post, standardization is there to make your lives easier. But it takes a lot of commitment, especially if your network has gone through significant “organic growth”. Making the choice to commit to good configuration management hygene is sort of like committing to going to the gym or commiting to eat healthier.
Just like going to the gym, the first thing you need to do is figure out your current software state. Hopefully, your NMS software will have the ability to discover and audit the software running on the devices in your network and report against a known good state.
Audit the Current State of the Network
If you don’t have an NCCM tool in place with these features, you may end up writing scripts, or worse case, loging into your devices manually and noting the software version in an excel spreadsheet. Once you have a handle on what’s out there, the next step is chosing what version of code you need to be running.
Choosing your Software Version
So now that you’ve figured out that your devices are all over the place, it’s time to figure out what version of software you actually want to be running. Whether you are running Comware, IOS, NXOS, Junos, FTOS, or some other OS that I haven’t mentioned, the guidelines are pretty much the same.
Wash, Rinse and Repeat.
What about the exceptions?
I was going to try to sugar coat this, but I’ll just come out and say it. Cisco has licensing for many of their platforms, this can create situations where you can’t actually get on a common code version without incurring additional CAPEX costs associated with buying the licenses and OPEX to deal with the SMARTNet’. Or potentially, you can get into the situation where the features you’re looking for are mutually exclusive in two different IOS images for your routers. Or you’re running Cisco Callmanager and your gateways require the Voice image and your regular WAN routers another image.
In any event, my recommendation is still the same. Find the fewest possible combinations of software for the hardware platforms in your network and stick to them unless there is a REALLY good reason to change.
Check out this video of the basic NCCM features in HP’s Intelligent Management Center to help you navigate through your software baseline woes.
Anything I missed here? Feel free to post in the comments below.