HA for istio-sidecar injector is not working as expected

Performance and Scalability
1

I am using istio 1.3 and have used helm to generate istio manifests. I have used the below configuration to ensure that I have 2 replicas of istio-sidecar-injector.

sidecarInjectorWebhook:
rewriteAppHTTPProbe: true
replicaCount: 2

Observer behavior: Only one pods appears to be handling all the traffic, though both the pods are in running state and there are endpoints associated with both the pods. I see AdmissionReview/ AdmissionResponse messages in the logs for only one pod and not the other. I have made almost 40 sidecar injection requests and they all were handled by only one pod.

Expected behaviour: If there are multiple replicas for any service, the expectation is that the requests should be equally distributed, but I do not see that happening.

Has anyone been able to configure HA for istio sidecar-injector service? How was it tested?

2

Is this on EKS by any chance? I think there was a bug there where it doesn’t handle multiple replicas well

3

Thanks John. Yes, this is on EKS. Will you be able to point me to the bug Id ?