As I described in the introduction to this series, I’ve used the acronym C3-P-O as a tool to help the teams I lead remember some key principles for maintaining a healthy infrastructure environment. This post is about the second “C” in the acronym - Currency.
Maintaining software and hardware currency in technology infrastructure is critical for ensuring stability, security, and supportability. While you absolutely need to work to keep things current, this doesn’t mean that you should take up every new model, software update, or firmware update immediately on release. Currency maintenance demands a measured approach in order to maintain the principle of Consistency.
In the anecdote that I shared in the introduction to this series, I mentioned the approach taken by previous leadership in the network team to “let sleeping dogs lie”, which led to equipment in our environment being literally years behind on code versions. While this approach seems to makes sense for minimizing work and the disruptions that code upgrades can cause, it’s a false economy. Eventually those aged versions of code are going to bite you in the ass when the equipment vendor refuses to support you in the middle of an incident, or you need to execute an emergency multi-hop upgrade to close a critical CVE. A resonable approach is to look to your equipment vendors for “safe-harbor” code versions as input into your standard release program. Unless absolutely necessary, you should try to stick to mainstream code trains and avoid taking up new versions before a good installed base is in place (your vendors should be able to tell you breadth of deployment across their customer base by version).
As you build up consistency of currency across your environment, staying current becomes easier, especially if you’re building automation along the way to do the heavy lifting. You’ll gain confidence in the tools, the incremental changes will get smaller, and the incidents of “outages caused by change” will become fewer in number. It’s a virtuous cycle.
Next up, Continuity!
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