This solves a huge gap. Blue/green and canary rollout is critical for highly-available services.
We'd been half-solving it by doing a "sandbox" deploy, running a health check, then "promoting" to prod by then deploying to our prod environment. Automatically, without manual steps or verification, of course. But it's not true blue/green like this, doesn't account for accidental environment parity issues or drift, and doesn't accommodate canary rollout.
