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PREQUEL-2025-0002

Envoy metrics scraping failure with unexpected EOFMedium
Impact: 7/10
Mitigation: 3/10

PREQUEL-2025-0002View on GitHub

Description

Prometheus is failing to scrape and write Envoy metrics from Istio sidecars due to an unexpected EOF error. This occurs when trying to collect metrics from services that don't have proper protocol selection configured in their Kubernetes Service definition\n

Mitigation

Add the appProtocol: http field to the port definition in the Kubernetes Service:\n\n```yaml\napiVersion: v1\nkind: Service\nmetadata:\n name: some-service\nspec:\n type: ClusterIP\n ports:\n - name: web\n port: 9898\n protocol: TCP\n targetPort: 9898\n appProtocol: http\n```\n\n- Alternatively, ensure port naming follows Istio convention (http-*, http2-*, grpc-*, etc.)\n- Restart affected services after configuration changes\n- Verify Prometheus is properly configured with tls_config for scraping Istio-enabled services\n

References