caveat lector: my sysadmin experience is all in Linux, I can't speak to life as Windows admin, but I bet it's pretty similar.

> Am I kidding myself by attempting to go down this road? Is it too late for a career change?

The only answer I can give here is - it depends. The key skills of a sysadmin are being able to figure out why a system is not behaving as expected, and then fix it quickly (usually in a high pressure situation).

This is intentionally vague - the point is that as a sysadmin, you will frequently be expected to be handed a black box problem with a vague description like "the website stopped working" - it's your job to figure out why it's not working - is it the webserver, the database, the app, a networking issue, a hardware issue, a service provider issue, ...? Over time, you start to pick up a lot of domain-specific knowledge (e.g. "I bet that zookeeper server had an OOM error again", "Systemd probably renamed the NIC after the reboot", ...)

Of course, it's not possible to know everything about every possible combination of software, so you also need to be good at rapidly determining what you need to know next in order to continue diagnosing/solving the problem.

You really only get good at this stuff with experience, and most entry-level sysadmins have picked up their early experience via a lot of hobbyist projects, and trying to fix their own broken machines.

You'll quickly find the need to get good at scripting (e.g. BASH), and you'll most likely need to get back into programming.

> Are certifications worth pursuing (CompTIA, RHCSA, AWS, etc)?

You've got to be careful with certs. A lot of people will actually think less of your resume if you have a bunch of certifications, usually because they have been burned before hiring someone with a bunch of certifications who had no idea what they were doing.

The best advice here is to search job listings for the certification you're considering - if there are a bunch of jobs that sound interesting that require or prefer that cert, then go for it. Of those you listed, I'd go for the AWS cert.

> How future proof is it as a career?

This really depends on your ability to keep learning as technology progresses. FWIW, (antecdotaly) it seems there is less age discrimination in the SysAdmin/Ops space than in the Software Engineer space. YMMV.

Still interested? Cool, here's some more practical advice (kind of general, because I don't know your skill-set):

1) Set up a home lab -- this doesn't need to be anything fancy, just a linux box on which you can run a few virtual machines.

2) Start going through a bunch of tutorials using your new lab -- e.g. build a simple website with something like Flask, and try to get it running like a production site (behind a webserver, with an external database..search for "run <web app framework> in production", and "<web app framework> high availability"). Configure various services on different VMs and network them together. Break things, see what the errors look like, then fix what you broke.

3) Start automating -- you've been building a lot of VMs at this point, figure out how to automate that. Write some custom scripts, play around with configuration management frameworks.

4) Setup centralized logging, monitoring, and alerting for the stuff you built in your VMs

5) Learn containers -- start with basic Docker; again look for some tutorials, build, break, fix, repeat.

6) Learn about running containers in production -- kubernetes is current king.

7) Build a new lab on an IaaS (cloud) platform -- AWS is a safe bet.

8) Keep lots of notes. Build yourself a knowledge base of everything you have learned, problems, solutions, scripts, etc.

9) Get good at programming, or at least learn good programming practices -- use version control (git), automated testing, continuous integration, etc.

10) Practice soft skills -- You need to be able to get people to describe the problems they're having (gently coaxing them into giving you more details); you need to be able to write effectively for documentation, status reports, post-mortems, etc.

11) Try to find a mentor, either in person or online. I know this is easier said than done. In any case, start chatting with people in domain-specific chatrooms. When you hit a roadblock in one of your projects above, find a community and start asking questions (protip: give sufficient detail about your issue when asking questions for better responses). If you can make friends here, they might be able to help you get a job.

Once you're getting comfortable with the above tasks:
12) Move beyond the sysadmin title -- learn about DevOps and Site Reliability Engineering; once you've followed the roadmap above, and have a couple of years experience as a SysAdmin, you can make significantly more money in DevOps or SRE.

I truly hope this isn't discouraging. There's a lot to know, but hopefully this type of learning is fun for you. Once you have a good general-knowledge base, you can start specializing in things that interest you, and make a lot more money.

Feel free to ask questions; I'll do my best to answer.

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One more thing: If you can find an entry level job you can get while ramping up your skills, go for it! It's always better (for you) to let someone else pay for your training.

(EDIT: minor clarifications)