Rollback & traffic split

Every kn-next deploy produces a new Knative Revision — an immutable snapshot of the pod template. Knative keeps prior revisions around, so rolling back is never a rebuild: it is purely a traffic decision. knext exposes that decision as a CR patch.

The CLI never touches the Knative Service, Route, or kn directly. kn-next rollback issues exactly one cluster write — a merge-patch of the NextApp CR's spec.traffic — and the operator renders that into the Knative Service's traffic targets.

kn-next rollback  →  kubectl patch nextapp … spec.traffic
operator          →  renders ksvc.spec.traffic
Knative Route     →  shifts revision traffic

The command

# Revert to the latest-ready revision (clear any pin)
kn-next rollback storefront

# Pin 100% of traffic to a specific prior revision
kn-next rollback storefront --to storefront-00002

# Canary: send 20% to latest-ready, 80% to the pinned revision
kn-next rollback storefront --to storefront-00002 --canary 20

What gets patched

The TrafficSpec on the CR has two fields — revisionName and canaryPercent:

# kn-next rollback storefront --to storefront-00002
spec:
  traffic:
    revisionName: storefront-00002

# kn-next rollback storefront --to storefront-00002 --canary 20
spec:
  traffic:
    revisionName: storefront-00002
    canaryPercent: 20

# kn-next rollback storefront  (no --to)
spec:
  traffic: null        # cleared → operator emits no spec.traffic → 100% latest-ready

How the operator renders it

The operator maps spec.traffic to Knative traffic targets:

Observing the live split

The operator mirrors the Knative Service's observed traffic back into NextApp.status.currentTraffic, so the live split is readable straight off the CR:

kubectl get nextapp storefront -o jsonpath='{.status.currentTraffic}'

Each entry carries revisionName, percent, and latestRevision.

Related

• Operator & the NextApp CRD — the traffic spec field and currentTraffic status field.
• Scale to zero — how revisions scale independently.
• Skew protection — why a rolled-back build keeps working.