Top 8 Rollback Interview Questions
Browse 8 real-world technical and behavioral interview questions about Rollback. Review scenarios, edge cases, and architectural best practices.
You are on call, a deploy went out twenty minutes ago and production is degraded. Talk me through what you do.
Stabilise first and diagnose second, which usually means reverting the change before you understand it. Take one artefact of evidence on the way out, time-box the decision aloud, communicate impact on a fixed cadence, and treat the incident as open until the damage the deploy caused is repaired.
Both the old and the new system are running side by side. How do you decide the day you switch customers over, and what does rollback mean once you have?
Write the entry criteria before the parallel run begins so the decision is a checklist rather than a mood, ramp through a stepped population with an abort condition at each step, and recognise that rollback stops meaning redeploy once the new system takes its first authoritative write.
How would you design a deployment pipeline that can be rolled back safely?
Build one immutable artefact, promote that same artefact through environments behind ordered quality gates, and deploy so traffic can be shifted back instantly. Rollback only stays possible if schema changes are backward-compatible expand-contract steps decoupled from the code deploy.
Walk me through what rollback netcode does on a single frame, and what it costs to run it.
Rollback netcode predicts remote input so local gameplay never waits for the network. When the real input arrives, the client restores the saved state from that frame and re-simulates forward, trading CPU and correction artifacts for responsive controls.
You have to release a change to the order-routing path. Walk me through the release, and tell me what makes it different from deploying any other service.
The gateway owns state you cannot drain, namely resting orders at the venue and sequenced sessions, so a rolling deployment leaves a mixed fleet holding live obligations. Verification has to be a position reconciliation rather than a health check, rollback does not undo executions, and dead code must be deleted rather than disabled.
How do you roll back a model in production?
Re-pointing traffic at the previous version is only safe if nothing else moved with it. The feature transformations, the input schema and any consumer calibrated to the current score distribution may have changed, so the unit of rollback is the model plus its features and its contract.
Some of what you ship - rules files, config bundles, model updates - reaches production without passing through the deploy pipeline. What would you put around that path?
Treat any payload the fleet loads as a release, because it changes behaviour in production exactly as a binary does. It needs schema and replay validation, a canary ring with its own health comparison, and a rollback that survives the change breaking whatever would apply the rollback.
The inner service threw, you caught the exception in the caller, and then the commit failed with UnexpectedRollbackException. Why?
The inner method joined the caller's transaction, so its rollback rule marked the one physical transaction rollback-only. Catching the exception hides it from your code but not from the transaction manager, which then refuses to commit. Use REQUIRES_NEW when the inner work must be able to fail alone.