And, to be
quite honest about this particular case ... this subject ("virtualization administration") is an area-of-knowledge that I call "a 'slice' vertical." It's a niche of specialized know-how that not-only consists of some rather esoteric information, but also that exists in a much greater context. You have to know, not only about the [Red Hat ... but it doesn't have to be Red Hat] host, but also about the systems that are being virtualized
and, really, the business that's running them and why. "The whole shinola."
Therefore, "reading a book about it" might be like "reading a book about swimming." (i.e.
"That won't keep you from drowning.") In this case, I think you
need to be signed-up for a
class, and not the cheapest one you might find. You need to be in the immediate company of other people, instructors, software and hardware for many days. And your
employer should be the one footing the entire bill for you.
Certifications are just things that you hang on the wall. Like that bachelor's degree that you got in "Appreciation of 17th Century Art History."
Even though there's always someone out there who's willing to sell it to you, it won't do a thing for you by itself. The more-esoteric the subject matter becomes, the more you need a classroom and time. This costs some serious money, if done properly, and your
employer should be willing to invest it in you.