My suggestion is that you "talk it up" starting at the place where you now work. If you express an interest in a particular career-direction, "bloom where you are planted." Don't assume that you will get fired for asking. Quite probably, within any company of any decent size, you will find something that needs to be done which will be in the direction that you now wish to go.
There is no substitute for experience. You can't learn how to swim by reading a book on swimming. And, every swimming-pool out there has a different set of sharks in it.
I do not find certifications to be useful, but I
do like to pick-up certification training manuals at used book stores on the dollar table because these
are generally good self-education materials. You'll get a pretty good idea of what the course-of-study is that the developer of the course – who will be a professional education designer – has laid out, and it's a good bet that he or she considered that to be reasonably representative of what sort of things you'd be doing and that you'd need to know on-the-job. Naturally, the course will be vendor-specific ... "Red Hat's course" will only speak of Red Hat and might shun every one else ... but you can see-through that smoke screen easily enough, and who knows, there might be another vendor's book on the same dollar table. You don't need to fork out a bunch of cash to get their certificate to hang on your wall, but you can benefit greatly from vicariously studying their materials. (Take note of
what they discuss, what they present and in what order they present it.)
You'll be self-educating all your life. Poking your head and fingers into some new area because you wanted to or because someone else wanted you to or both. At first, feeling
"the sip from the firehose." Always. But then,
somehow figuring it out anyway. That's a big part of what makes this business
fun, albeit in a weird sort of way.