migration

Sets instead of thousand-rule chains, one engine for both IP families, atomic ruleset swaps, and a compatibility shim with sharp edges. Migration risk lives in coexistence and tooling assumptions, not syntax.

The services-and-enterprise interview staple. There is a defensible answer and it is not 'always re-platform': the decision is a function of change tolerance, deadline reality and what the workload is worth.

The services-market question that decides who can actually run a migration. Import is the easy part; the hard parts are resource-for-resource fidelity and proving the first plan is empty.

An end-of-maintenance date changes the risk even while traffic stays healthy. The work is proving routing and security parity before moving a production hostname.

The deployment question that has a real answer and a real trap. Code and schema deploy at different speeds, and any step where they must change together is the step that causes the outage.

OpenTelemetry is an API and a wire protocol, not a product. Candidates who promise instant multi-vendor bliss have never run the collector in production or negotiated with a vendor who knows it.

The migration question, and the trap is answering with a target architecture. What is being scored is sequencing: how you get there without a rewrite and without a release freeze.

Sharding buys write headroom and bills you in joins, foreign keys, and every future migration. The key choice is a query-pattern bet; the resharding choreography separates operators from diagram artists.