A practical server migration checklist
Write this down before you lower the DNS TTL.
The checklist
- Inventory hosts, reverse proxies, certificates, cron, queues, env files and “that one firewall rule”.
- Agree the target architecture and what will not move.
- Lower DNS TTLs early enough to matter.
- Copy data with a method that matches database size and write rate.
- Issue or transfer TLS so HTTPS is ready before cutover.
- Validate on the new origin using hosts-file or staging DNS, not hope.
- Cut over with an owner, a clock and a rollback trigger.
- Watch logs, queues and certificates for a defined soak period.
Downtime is a design choice
Zero downtime is a design and a contract, not a slogan. If the application cannot run in two places, plan the interruption.