Envoy defaults set by App Mesh

The following sections provide information about 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, 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 was created for any Envoy routes that existed before, on, or after July 29, 2020. This is unless you open a ticket with AWS support. After support processes the ticket, the default policy is 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 isn't 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 retries – 2

• gRPC retry events – UNAVAILABLE

• HTTP retry events – 503

  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. Both of these include 503 errors. For more information, see Routes.

• TCP retry event – connect-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 attempts a retry if the upstream server doesn't 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. These settings aren't 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, 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_requests – 2147483647

• max_pending_requests – 2147483647

• max_connections – 2147483647

• max_retries – 2147483647

Note

No matter if your Envoys have the Envoy or App Mesh default circuit breaker values, you cannot modify the values.