Inject an annotation into every Istio sidecar

You do not have to edit every deployment to put a sidecar annotation on your workloads. Istio's injector can stamp a fixed annotation onto every pod it injects, from one place in the mesh config: values.sidecarInjectorWebhook.injectedAnnotations.

I wanted every sidecar in the mesh to carry sidecar.istio.io/statsEvictionInterval without touching hundreds of deployments:

# IstioOperator
spec:
  values:
    sidecarInjectorWebhook:
      injectedAnnotations:
        sidecar.istio.io/statsEvictionInterval: "120s"

Every pod the sidecar injector touches comes out with that annotation, so the whole mesh picks it up on the next rollout. No per-deployment edits, no mutating hundreds of manifests.

Read it back off a running pod to confirm:

kubectl get pod <pod> -o jsonpath='{.metadata.annotations.sidecar\.istio\.io/statsEvictionInterval}'

One thing to know before you lean on it: a value set here also overrides a pod that sets the same annotation itself. That is its own note: a mesh-wide injected annotation overrides the pod's own.

Docs: installing the sidecar, and the injectedAnnotations field in the inject package (istio.io/istio/pkg/kube/inject).