Retry Strategy

The pattern

A retry setting specifies the maximum number of times an Envoy proxy attempts to connect to a service if the initial call fails. Retries can enhance service availability and application performance by making sure that calls don’t fail permanently because of transient problems such as a temporarily overloaded service or network.

A retry is configured using two fields:

• attempts: The number of retries before activating a circuit breaker.

• perTryTimeout: the timeout per each request.

How it works

The Fault injection is handled by the following Istio Object:

Retry in practice

1. We will configure shippingservice to have three times retry in case of failures, this increasing the chance of resulting in a successful response in case of temporary outage. we configure also the retry time to 3 seconds.

   apiVersion: networking.istio.io/v1alpha3
   kind: VirtualService
   metadata:
   name: shippingservice-retry
   spec:
   hosts:
   - shippingservice
   http:
   - route:
   - destination:
       host: shippingservice
   retries:
     attempts: 3
     perTryTimeout: 3s
   

2. Apply the configuration with the command below:

   kubectl apply -f $WORKSHOP_HOME/istio-workshop-labs/shippingservice-retry.yaml