Changing domain’s IP address when a remote service is actively using the domain.
Note that the remote service must support automatic queuing+re-delivering.
- Reduce DNS ip TTL from L to N minutes.
- Make snapshot A on the old instance and apply it to the new instance.
- Run the new instance and test it works fine.
- Make sure L minutes passed since step 1.
- — Downtime starts here —
- Stop the old instance and make data snapshot B from it.
- Rsync full snapshot B to the new instance (adding/updating/deleting the files).
- Change the DNS IP address to the new instance.
- — Downtime ends here —