How to fix EnvoyFilter rejected, validation failed, sync failed in Kubernetes

KubernetesADVANCEDMEDIUM

EnvoyFilter configuration rejected by Istio control plane due to invalid spec. Fix by validating Envoy configuration, checking Istiod logs, and testing with simple config.

What this error means

Istio's Envoy proxy supports advanced traffic routing via EnvoyFilters. Invalid configurations are rejected by Istiod (Istio control plane).

Typical symptoms

Pod doesn't receive EnvoyFilter
Istiod shows validation errors
Traffic continues with old config
No error in kubectl describe

Common causes

Invalid Envoy configuration syntax
Unsupported Envoy API version
Missing required fields
Version mismatch between Istio and Envoy

How to fix "EnvoyFilter rejected, validation failed, sync failed"

1Check EnvoyFilter status

bash

kubectl describe envoyfilter -n <namespace> <name>

2Check Istiod logs

bash

kubectl logs -n istio-system -l app=istiod | tail -50

3Validate configuration

Test Envoy config syntax locally.

4Simplify config

Start with minimal working config, then add features.

Advanced notes

Use istioctl analyze to validate configuration.

Related errors

Official resources & further reading

📚Kubernetes Official Documentation
📖
EnvoyFilter - Istio Docs(Official Docs)