What is the best way to administer multiple servers?

Question

System administration

Hello!
It becomes not enough to have 2 servers on a project. 1 for the base, the other for the code. The need for a balancer began to appear + 1 server for code and 1 for database replication, etc. Moving the partner site parser to a separate machine, since it works 24 hours.
What is the best way to administer a group of servers? Update them, keep the code up to date on all servers, monitor? Are there finished products? Windows Azure? Is cloud hosting worth it? Are they more expensive than flat fee hosting? For example, on a server with a database, reading and writing are constantly going on, since partner sites are being parsed.

Answer 1

You have questions for a whole book, honestly. Read habr.

Answer 2

It depends on what you mean by the word "administrate". Definitely need to look at virtualization systems like vmvari or hypervi. + raise the centralized management of them.

Answer 3

I think you just need to start somewhere and not be tormented by questions. And the solution will come by itself.
In any case, your task is the simplest and there is actually nothing to administer there.