I initially created an EnvoyFilter to apply idle_timeout of 5s to outbound requests originating from workloads with label app: mecha-dev.

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
  name: tcp-idle-timeout
      app: mecha-dev
    - listenerMatch:
        listenerType: SIDECAR_OUTBOUND
        listenerProtocol: TCP
      filterName: envoy.tcp_proxy
      filterType: NETWORK
        idle_timeout: 5s

However, the filter did not work for me and I found out it was because my cluster is using istio v1.2.5 which is a very old version and does not support EnvoyFilters properly and the envoy API for the same have been deprecated.

Therefore, I deleted the EnvoyFilter using kubectl.

But, even after deletion of the filter the istio-proxy sidecar containers keep on showing me the following error again and again:

[2021-05-11 11:59:14.109][22][warning][config] [external/envoy/source/common/config/grpc_mux_subscription_impl.cc:73] gRPC config for type.googleapis.com/envoy.api.v2.Listener rejected: Error adding/updating listener(s) Proto constraint validation failed (TcpProxyValidationError.StatPrefix: ["value length must be at least " '\x01' " bytes"]): idle_timeout {
  seconds: 5

I deleted the pods and re-created new ones but this error keeps on showing up. Is there anything else I need to clean up or delete to get rid of this error?

  • 1
    Have you deleted workloads only? Have you restarted controlplane as well (pods in istio-system namespace)?
    – Kyslik
    May 12, 2021 at 10:42
  • @Kyslik there are a bunch of pods in istio-system namespace, do I gotta restart all?
    – bakadevops
    May 12, 2021 at 11:44
  • 1
    Unless you run your production workloads on that cluster, yes. You gotta test things like this one way or another... I don't remember what components Istio 1.2 have, but I'd start with pilot or mixer.
    – Kyslik
    May 12, 2021 at 11:48
  • 1
    It is not a prod workload so I can test these out.
    – bakadevops
    May 12, 2021 at 11:49
  • 1
    @Kyslik after restarting pilot and mixer the errors were gone. Thanks for the suggestion.
    – bakadevops
    May 12, 2021 at 13:19

1 Answer 1


Restarting Istio controlplane should fix the issue on hand (pods in istio-system, most likely pilot).

More importantly do not run Istio 1.2 its very outdated version with many bugs and security issues.

  • Yes, we are abolishing the old version. This was just a plan to mitigate some connection issues while we setup our new clusters with latest istio.
    – bakadevops
    May 12, 2021 at 17:58

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