How does DocEvent manage scaling?

Our service runs in multiple auto-scaling clusters to verify changes and ensure high availability as they are rolled out to production.

The process of taking a server out of the cluster during an auto-scale event means it can affect long-running connections to our servers.

Our clusters are built to wait for connections to finish their work before shutting down, like so:

1. Remove server from DNS
2. Wait for DNS propagation and DNS TTL expiry
3. No longer accept new connections
4. Wait for connections to close with a timeout
5. Shutdown the server

This process ensures any FTP uploads and downloads are completed before any scaling event is finalised.