Quick server change?

Question

Domain Name System

Brothers and sisters who have experience with web server quick reconfiguration, please answer this question:
There is a certain web service that has regular visitors and server A (at the moment, VPS, power, etc. do not matter ), but I want to change this server to a more powerful, weaker (underline as necessary) server B, which has a different DNS address. Actually the question is: how to make the DNS change time reduced to the minimum possible, or is there any way to bypass this timeout and carry out a “hot” change of servers.
Thank you very much in advance for your replies.

Answer 1

At the time of the server change, put nginx on server A, which will transfer requests to server B.

Answer 2

+1 for nginx (any other tool of this type)
And if you do this using DNS, then you need to set the minimum TTL value for the A-record, 60-300 seconds will be fine.

Answer 3

by TTL - if you shorten it, do it in advance, because TTL, like the zone records themselves, remains in the DNS cache

Answer 4

any web server can proxy requests, not only nginx )
and by the way, about hosts - you don’t need to do this. Web servers do not use DNS in their work. You can ask any web server to "show the site vkontakte.ru".
Specify backend IP and port in proxy_pass.
Well, yes - be careful with traffic, it will be symmetrical.