Envoy defaults set by App Mesh - AWS App Mesh

Envoy defaults set by App Mesh

The following sections provide information on the Envoy defaults for the route retry policy and circuit breaker that are set by App Mesh.

Default route retry policy

If you had no meshes in your account before July 29, 2020, then App Mesh automatically creates a default Envoy route retry policy for all HTTP, HTTP/2, and gRPC requests in any mesh in your account on or after July 29, 2020. If you had any meshes in your account before July 29, 2020, then no default policy is created for any Envoy routes that existed before, on, or after July 29, 2020, unless you open a ticket with AWS support. Once support processes the ticket, then the default policy will be created for any future Envoy routes that App Mesh creates on or after the date that the ticket was processed. For more information about Envoy route retry policies, see config.route.v3.RetryPolicy in the Envoy documentation.

App Mesh creates an Envoy route when you either create an App Mesh route or define a virtual node provider for an App Mesh virtual service. Though you can create an App Mesh route retry policy, you can't create an App Mesh retry policy for a virtual node provider.

The default policy is not visible through the App Mesh API. The default policy is only visible through Envoy. To view the configuration, enable the administration interface and send a request to Envoy for a config_dump. The default policy includes the following settings:

  • Max retries2

  • gRPC retry eventsUNAVAILABLE

  • HTTP retry events503

    Note

    It's not possible to create an App Mesh route retry policy that looks for a specific HTTP error code, however an App Mesh route retry policy can look for server-error or gateway-error, which both include 503 errors. For more information, see Routes.

  • TCP retry eventconnect-failure and refused-stream

    Note

    It's not possible to create an App Mesh route retry policy that looks for either of these events, however an App Mesh route retry policy can look for connection-error, which is equivalent to connect-failure. For more information, see Routes.

  • Reset – Envoy will attempt a retry if the upstream server does not respond at all (disconnect/reset/read timeout).

Default circuit breaker

When you deploy an Envoy in App Mesh, Envoy default values are set for some of the circuit breaker settings. For more information, see cluster.CircuitBreakers.Thresholds in the Envoy documentation. The settings are not visible through the App Mesh API. The settings are only visible through Envoy. To view the configuration, enable the administration interface and send a request to Envoy for a config_dump.

If you had no meshes in your account before July 29, 2020, then for each Envoy that you deploy in a mesh created on or after July 29, 2020, App Mesh effectively disables circuit breakers by changing the Envoy default values for the settings that follow. If you had any meshes in your account before July 29, 2020, then the Envoy default values are set for any Envoy that you deploy in App Mesh on, or after July 29, 2020, unless you open a ticket with AWS support. Once support processes the ticket, then the App Mesh default values for the following Envoy settings are set by App Mesh on all Envoys that you deploy after the date that the ticket is processed:

  • max_requests2147483647

  • max_pending_requests2147483647

  • max_connections2147483647

  • max_retries2147483647

Note

Whether your Envoys have the Envoy or App Mesh default circuit breaker values, you are not able to modify the values.