Application migration

Moving a running application to AWS is three jobs in sequence: find out what is actually running and what talks to what, replicate the servers into AWS and cut over, then keep the interfaces the rest of the business depends on working.

AWS Transform MGN is the rehosting tool — continuous block-level replication of physical, virtual and other-cloud servers into EC2, with a test launch before cutover. Discovery and wave planning now sit in AWS Transform itself; the older Application Discovery Service and Migration Hub pages explain what those services did and why a new account can no longer use them.

AWS Transfer Family is the piece that usually survives the migration: partners and legacy applications keep speaking SFTP or AS2, and the files land in S3 instead of on a server somebody has to patch.

For choosing whether to rehost at all, see the seven migration strategies.