重新启动实时的node.js服务器而不关闭套接字？

Question

We have a small set of multiplayer servers using node.js that are currently serving roughly 1 million messages a minute during peak usage. Is there a way to 'gracefully' restart the server without causing sockets to drop? Basically, I'm wondering what is the best way to handle restarts were it would normally be very disruptive to players?

Answer 1

use redis or some in-memory database for storing connection so that you can easily reconnect even after server restart without loosing any sessions or connection. Try this if it suits your need. Also please note during restart connection may drop but due to having persistence you will be connected again very easily. socket.io-redis

Answer 2

When a process exits, the OS cleans up any sockets that belong to it by closing them. So, there's no way to just do a simple server restart and preserve your socket connections.

In some operating systems, you can pass ownership of a socket from one process to another so it might be technically feasible for you to create a temporary process or perhaps a previously existing parent process), pass ownership of the sockets to that other process, restart your server, then transfer ownership back to the newly started process. I've never tried this (or heard about it being done), but it sounds like something that might be feasible.

Here's some information on transferring a socket to a child process using child.send() in node.js. It appears this can only be done for a node.js socket created by the net module and there are some caveats about doing it, but it is possible.

If not, the usual work-around is have the clients automatically reconnect when their connection is closed. Done properly, this can be fairly transparent to the client (except for the momentary time when the server is not running).