Use the Backend custom resource

With the Backend custom resource, you can manage how traffic is load balanced across pods. To use it:

1. Create a YAML file that declares a Backend resource and add properties to its spec.config section.

   In the example below, the balance.algorithm property changes the load balancing algorithm to least connections.

   example-backend.yaml

   apiVersion: "core.haproxy.org/v1alpha1"
   kind: Backend
   metadata:
     name: example-backend
     namespace: default
   spec:
     config:
       balance:
         algorithm: "leastconn"

2. Deploy it to your cluster using kubectl apply.

   $ kubectl apply -f example-backend.yaml
   

3. Decide which Kubernetes services the resource should apply to. Do one of the following:

   • To have the properties apply to all services, create a new ConfigMap with the name haproxy-kubernetes-ingress to override the one that ships with the ingress controller. Add the cr-backend key to the data section to implement the backend properties.

     example-configmap.yaml

     apiVersion: v1
     kind: ConfigMap
     metadata:
       name: haproxy-kubernetes-ingress
       namespace: haproxy-controller
     data:
       cr-backend: default/example-backend

     Update the ConfigMap in your cluster by using kubectl apply:

     $ kubectl apply -f  example-configmap.yaml
     

   • To have the properties apply to all services that the Ingress routes traffic to, add the cr-backend annotation to your Ingress definition . The Ingress below applies to the services example-service1 and example-service2:

     example-ingress.yaml

     apiVersion: networking.k8s.io/v1
     kind: Ingress
     metadata:
         name: example-ingress
         annotations:
            haproxy.org/cr-backend: default/example-backend
     spec:
         rules:
         - http:
             paths:
             - path: /example1
               pathType: Prefix
               backend:
                 service:
                   name: example-service1
                   port:
                     number: 80
             - path: /example2
               pathType: Prefix
               backend:
                 service:
                   name: example-service2
                   port:
                     number: 80

     Update the Ingress in your cluster by using kubectl apply:

     $ kubectl apply -f  example-ingress.yaml
     

   • To have the properties apply to only a specific Kubernetes service, add the cr-backend annotation to your Service definition. The Service below applies the properties only to the service named example-service1.

     example-service.yaml

     apiVersion: v1
     kind: Service
     metadata:
       labels:
         run: app
       name: example-service1
       annotations:
         haproxy.org/cr-backend: default/example-backend
     spec:
       selector:
         run: app
       ports:
       - name: http
         port: 80
         protocol: TCP
         targetPort: 8080

     Update the Service in your cluster by using kubectl apply:

     $ kubectl apply -f  example-service.yaml
     

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