Retries
Specify the number of times and duration you want K8sGateway to try a connection to an unresponsive upstream service.
About retries
A retry specifies the maximum number of times K8sGateway attempts to connect to an upstream 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.
To configure retries, you can use the following settings in the RouteOption resource:
options.retries.retryOn
: The condition under which to retry forwarding the request to the upstream service. This setting exposes thex-envoy-retry-on
Envoy header.options.retries.numRetries
: The number of allowed retries. The default value is 1.options.retries.perTryTimeout
: The timeout duration for each retry attempt. This setting exposes the x-envoy-expected-rq-timeout-ms header.
Before you begin
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Follow the Get started guide to install K8sGateway, set up a gateway resource, and deploy the httpbin sample app.
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Get the external address of the gateway and save it in an environment variable.
export INGRESS_GW_ADDRESS=$(kubectl get svc -n gloo-system gloo-proxy-http -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}") echo $INGRESS_GW_ADDRESS
kubectl port-forward deployment/gloo-proxy-http -n gloo-system 8080:8080
Set up retries
Use a RouteOption resource to specify retries for a specific route.
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Create a RouteOption custom resource to specify your retry rules. In the following example, the request is retried up to 3 times when a connection failure is detected. For each retry a timeout of 5 seconds is set.
kubectl apply -n httpbin -f- <<EOF apiVersion: gateway.solo.io/v1 kind: RouteOption metadata: name: retry namespace: httpbin spec: options: retries: retryOn: 'connect-failure' numRetries: 3 perTryTimeout: '5s' EOF
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Create an HTTPRoute resource for the httpbin app that references the RouteOption resource that you created.
kubectl apply -f- <<EOF apiVersion: gateway.networking.k8s.io/v1 kind: HTTPRoute metadata: name: httpbin-retry namespace: httpbin spec: parentRefs: - name: http namespace: gloo-system hostnames: - retry.example rules: - filters: - type: ExtensionRef extensionRef: group: gateway.solo.io kind: RouteOption name: retry backendRefs: - name: httpbin port: 8000 EOF
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Send a request to the httpbin app on the
retry.example
domain. Verify that the request succeeds and that you see aX-Envoy-Expected-Rq-Timeout-Ms
header. If the header is present, K8sGateway expects requests to the httpbin app to succeed within the set timeout.curl -vik http://$INGRESS_GW_ADDRESS:8080/headers -H "host: retry.example:8080"
curl -vik localhost:8080/headers -H "host: retry.example"
Example output for a successful response:
{ "headers": { "Accept": [ "*/*" ], "Host": [ "timeout.example:8080" ], "User-Agent": [ "curl/7.77.0" ], "X-Envoy-Expected-Rq-Timeout-Ms": [ "5000" ], "X-Forwarded-Proto": [ "http" ], "X-Request-Id": [ "0ae53bc3-2644-44f2-8603-158d2ccf9f78" ] } }
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Optional: Remove the resources that you created.
kubectl delete httproute httpbin-retry -n httpbin kubectl delete routeoption retry -n httpbin