1. Progressive Delivery advanced

    Your canary analysis compares the canary's error rate against current production. Results are noisy and unreliable. What is methodologically wrong?

    2 min answer netflixcanarystatisticsmethod
  2. Progressive Delivery advanced

    Your service handles 40 requests per minute. Product wants canary releases with automated analysis. What do you tell them?

    2 min answer canarystatisticsdeployment
  3. Rollback & Forward Fix advanced

    A background-job system has millions of queued jobs after an incident, and replaying them all at once will crash the databases. How should recovery be sequenced?

    2 min answer backlogreplaythrottlingprioritisation
  4. Rollback & Forward Fix advanced

    A change causes a global incident. When should you roll back and when should you fix forward, and what property makes the choice easy?

    2 min answer rollbackforward-fixincidentblast-radius
  5. Rollback & Forward Fix advanced

    An order service and a billing service deploy independently. Billing shipped a version at 09:00 that requires a tax_basis field on every message. Orders shipped at 10:00 and began emitting it. At 10:40 the orders release is causing checkout errors and the on-call rolls orders back. What happens next, and what property would have made that rollback safe?

    3 min answer rollbackcontractstolerant-readerdead-letter
  6. Supply-Chain Provenance advanced

    An auditor asks you to prove that the container running in production is the one that passed security scanning three weeks ago. What must be true?

    2 min answer supply-chainauditprovenance
  7. Supply-Chain Provenance advanced

    The xz-utils backdoor disclosed on 29 March 2024 (CVE-2024-3094) was present in the release tarballs for versions 5.6.0 and 5.6.1 but not in the equivalent state of the public git repository: the malicious build-to-host.m4 macro shipped only in the distributed archive and activated a payload hidden in test fixtures during the build. Which assumption in a normal supply-chain pipeline does this defeat, and what would have caught it?

    3 min answer xzsupply-chainprovenancereproducible-builds
  8. Supply-Chain Provenance advanced

    What does provenance add beyond signing, and what makes it usable rather than ceremonial?

    2 min answer provenanceattestationverificationinventory