I suggest you pick an LTS version of an OS that is extremely popular like Ubuntu. That way you will have lots of people paying attention and patching security f

I suggest you pick an LTS version of an OS that is extremely popular like Ubuntu. That way you will have lots of people paying attention and patching security flaws ASAP. Then make sure you update regularly/automatically. Put it behind a strong firewall, AWS makes this really easy but you can do everything you need to with iptables. Disable password based auth in ssh and force key auth. I disagree with yeukhon. You don't need to hire someone just because you asked that question. Unless you are storing highly sensitive data, then I'll leave that up to you. Just remember to constantly update your server.