Runbook

Missing ServiceEntry Configuration for Routing to Pod in Headless Service in Istio.

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Overview

This incident type is related to configuring a virtual service to route to a pod in a headless service using the ${pod name}.${service name}.${namespace}.svc.cluster.local naming in Istio. When attempting to analyze the configuration using "istio analyze", an error message "Referenced host not found" is encountered. The root cause of this error is the absence of a ServiceEntry configuration for that pod with "location: MESH_INTERNAL" and "resolution: DNS".

Parameters

Debug

Check that the problematic VirtualService contains the pod as a destination

Check if the headless service has a valid selector

Get the pods of the service

Check if the Istio sidecar is running and properly configured in the pod.

Check if the pods are resolvable from within the cluster

Check if a ServiceEntry is present with "location: MESH_INTERNAL" and "resolution: DNS"

Repair

Create a ServiceEntry configuration with "location: MESH_INTERNAL" and "resolution: DNS" to fix the missing configuration.

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