# Which namespace label tells Istio to inject sidecars from a specific control plane revision during a canary upgrade?

Istio, Easy (Beginner), Installation. https://k8wiz.com/uquiz/which-namespace-label-tells-istio-to-inject-sidecars-from-a-specific-control-plane-revision-during-a-canary-upgrade

- A. istio-injection=<revision>
- B. istio.io/rev=<revision>
- C. sidecar.istio.io/rev=<revision>
- D. istio.io/control-plane=<revision>

**Answer:** istio.io/rev=<revision>

**Explanation:** The istio.io/rev label selects the revision (or revision tag) whose injector handles pods in the namespace. The istio-injection label only takes enabled or disabled, and it takes precedence over istio.io/rev, so remove it when you switch a namespace to a revision.