How to make a copy of the site on the second server?

Question

System administration

There is a site in a closed network on wordpress, you need to make a copy on the second server, so that when one server is turned off, the site works from the second, and when the first one returns to the server, everything is synchronized with it.

Answer 1

You do database replication, a distributed network FS for files, scripts or some software implement failover in the form of switching DNS A-records and starting on the second database server for writing. Optionally, you make a balancer somewhere, then you don’t have to switch DNS and wait until the client’s cache runs out, but an additional point of failure appears.

Answer 2

as an option:
on the main and backup servers, organize access to the content servers through a proxy (nginx), and the proxy on the backup server redirects requests to the main content server. In an emergency, it switches to its own content server. You can again raise the proxy a little.