Course Info

How the release harness works

A short course on the Tutors release harness: the theory behind it, the design of its containers, the philosophy of A/A and A/B testing, the approach it takes from scripted traffic to a verdict, and the A3 that explains every night whether main is ready to become a release.

What is compared, and the Gate

Under the title, find the sentence that begins This sheet compares. It names:

  • the side b build: main at a short commit sha (a Main to RC forecast), or a release candidate;
  • the side a release: the production version it was judged against;
  • when the run happened.

Next to it is the Gate: PASS, WARN or FAIL, with the line under it saying why (for example every difference is claimed). If the Gate passed, the Release Confidence Score and its band follow, with the eight dimensions. A dimension marked n/m was not measured: it is left out of the score, never scored 100.

Check: is the production version the one students use today? If the sheet compares against an older release, every number below it describes the wrong gap.

Write down the verdict, the score and the band.