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Configuring a fallback service
Learn to setup a fallback service using Ingress resource. The fallback service receives all requests that don’t match against any of the defined Ingress rules. This can be useful if you would like to return a 404 page to the end user if the user clicks a dead link or inputs an incorrect URL.
Before you begin ensure that you have Installed Kong Ingress Controller in your Kubernetes cluster and are able to connect to Kong.
Before you begin ensure that you have Installed Kong Ingress Controller in your Kubernetes cluster and are able to connect to Kong.
Prerequisites
Install Kong
You can install Kong in your Kubernetes cluster using Helm.
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Add the Kong Helm charts:
helm repo add kong https://charts.konghq.com helm repo update
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Install Kong Ingress Controller and Kong Gateway with Helm:
helm install kong kong/ingress -n kong --create-namespace
Test connectivity to Kong
Kubernetes exposes the proxy through a Kubernetes service. Run the following commands to store the load balancer IP address in a variable named PROXY_IP
:
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Populate
$PROXY_IP
for future commands:export PROXY_IP=$(kubectl get svc --namespace kong kong-gateway-proxy -o jsonpath='{.status.loadBalancer.ingress[0].ip}') echo $PROXY_IP
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Ensure that you can call the proxy IP:
curl -i $PROXY_IP
The results should look like this:
HTTP/1.1 404 Not Found Content-Type: application/json; charset=utf-8 Connection: keep-alive Content-Length: 48 X-Kong-Response-Latency: 0 Server: kong/3.0.0 {"message":"no Route matched with those values"}
Setup a sample service
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Deploy an example echo service.
kubectl apply -f https://docs.jp.konghq.com/assets/kubernetes-ingress-controller/examples/echo-service.yaml
The results should look like this:
deployment.apps/echo created service/echo created
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Create an Ingress rule to proxy the echo service.
$ echo ' apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: demo annotations: konghq.com/strip-path: "true" spec: ingressClassName: kong rules: - http: paths: - path: /echo pathType: ImplementationSpecific backend: service: name: echo port: number: 1027 ' | kubectl apply -f -
The results should look like this:
ingress.extensions/demo created
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Test the Ingress rule:
$ curl -i $PROXY_IP/echo
The results should look like this:
HTTP/1.1 200 OK Content-Type: text/plain; charset=utf-8 Content-Length: 137 Connection: keep-alive Date: Sun, 17 Sep 2023 19:45:02 GMT X-Kong-Upstream-Latency: 1 X-Kong-Proxy-Latency: 0 Via: kong/3.3.1 Welcome, you are connected to node kind. Running on Pod echo-74d47cc5d9-9zbzh. In namespace default. With IP address 192.168.194.7.
Setup a fallback service
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Deploy another sample service service.
$ echo ' apiVersion: apps/v1 kind: Deployment metadata: name: fallback-svc spec: replicas: 1 selector: matchLabels: app: fallback-svc template: metadata: labels: app: fallback-svc spec: containers: - name: fallback-svc image: hashicorp/http-echo args: - "-text" - "This is not the path you are looking for. - Fallback service" ports: - containerPort: 5678 --- apiVersion: v1 kind: Service metadata: name: fallback-svc labels: app: fallback-svc spec: type: ClusterIP ports: - port: 80 targetPort: 5678 protocol: TCP name: http selector: app: fallback-svc ' | kubectl apply -f -
The results should look like this:
deployment.apps/fallback-svc created service/fallback-svc created
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Configure an Ingress rule to make it the fallback service to send all requests to it that don’t match any of the Ingress rules.
$ echo " apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: fallback annotations: spec: ingressClassName: kong defaultBackend: service: name: fallback-svc port: number: 80 " | kubectl apply -f -
The results should look like this:
ingress.networking.k8s.io/fallback created
Test the fallback service
Send a request with a request property that doesn’t match any of the defined rules:
$ curl $PROXY_IP/random-path
The results should look like this:
HTTP/1.1 200 OK Content-Type: text/plain; charset=utf-8 Content-Length: 61 Connection: keep-alive X-App-Name: http-echo X-App-Version: 0.2.3 Date: Wed, 20 Sep 2023 09:46:56 GMT X-Kong-Upstream-Latency: 16 X-Kong-Proxy-Latency: 0 Via: kong/3.3.1 This is not the path you are looking for. - Fallback service
This message is from the fallback service that you deployed.
Create more Ingress rules, some complicated regex based ones and see how requests that don’t match any rules, are forwarded to the fallback service.
You can also use Kong’s request-termination plugin on the fallback
Ingress resource to terminate all requests at Kong, without
forwarding them inside the infrastructure.