You can migrate Apollo Server (or other compatible server) to Apollo Federation with the following steps:
1. Create a gateway
The gateway will be the entry point to your graph that routes queries to various subgraphs. Please see our quickstart guide with examples
2. Convert and divide your existing GraphQL schema into multiple subgraphs
To convert your Apollo Server instance into a subgraph server, see this article
When deciding how to divide your existing schema across multiple subgraphs, check out the following resources: Federated schema design
3. Publish your subgraphs
With managed federation, we register each of our subgraph schemas with Apollo Studio.
Whenever a subgraph schema changes, you should register that change with Apollo Studio using the Rover CLI tool; Apollo Studio takes care of the rest, and compose the changes into an updated supergraph schema.
Please see the docs below to get started!