How to force Nginx to stop running users on a node?

Question

Nginx

Good afternoon!
There is an application on N nodes.
On average, a user's working session in the application lasts 1 hour.
Is it possible to run the following script:

• tell Nginx not to let new users into node N
  
• we wait until all users finish their work there
  
• restart the node
  
• let users in
  

?

Answer 1

And what about the nodes?
What kind of session is meant? If tcp, then why not remove the problematic node (down) in the configs and reload ndinks (without breaking current connections)?
If you mean a higher session at the level of a higher protocol, then you also need to know the nuances. Which backend, is it stateful, can another backend respond to the session of the previous one, etc.