Platform & DevOps·Pipelines, promotion and GitOps
the exact bytes tested in staging are the bytes that run in production, with only the configuration differing.
Build once, deploy many
Also calledbuild once deploy everywhere, single artefact promotion
The rule that an artefact is built exactly once and then promoted unchanged through environments, with environment differences supplied as configuration at run time. It is what gives testing in a lower environment any evidential value. Breaking it is usually accidental — an environment-specific build argument, a rebuild triggered by the deploy job — and the consequence is that every environment is a separate, untested thing.