Ask HN: Any suggestion about server administration tool for solo developer?

Hi to all, I am a solo developer working fulltime for a company.

I am developing a side project that hope to launch before the end of the year. I have basic knowdledge of server administration, let's say just enough to be dangerous :).

I have set up docker-compose configuration for my dev environment with the hope to gain "agility" when I'll need to go in production.

I keep reading that docker is not for production, So I am asking.. what is the best tool for my kind of situation? What should I focus on learning ?