internal-load-balancing.md

Internal Load Balancing

This section continues from the previous section - make sure you do the tutorial in sequence.

{% page-ref page="../service.md" %}

In-Cluster Load Balancer

A Kubernetes Service acts as an internal L4 load balancer only accessible from within the same Kubernetes Cluster. See the Service section for more information.

Internal Network Load Balancer

The setup of the Internal Network Load Balancer is similar to the External Network Load Balancer, but with an additional annotation.

Service YAML

In k8s/service.yaml, use the cloud.google.com/load-balancer-type annotation to mark the service to use the Internal Network Load Balancer:

{% code title="k8s/service.yaml" %}

apiVersion: v1
kind: Service
metadata:
  name: helloworld
  annotations:
    # Indicate this is an Internal Network Load Balancer
    cloud.google.com/load-balancer-type: "Internal"
  labels:
    app: helloworld
spec:
  ports:
  - name: 8080-8080
    port: 8080
    protocol: TCP
    targetPort: 8080
  selector:
    app: helloworld
  # Use LoadBalancer type instead of ClusterIP
  type: LoadBalancer

{% endcode %}

Internal Static IP

You can assign an internal static IP address to the Network Load Balancer.

Reserve a regional static IP address:

REGION=$(gcloud config get-value compute/region)

gcloud compute addresses create helloworld-service-internal-ip \
  --subnet=default --region=${REGION}

See the reserved IP address:

REGION=$(gcloud config get-value compute/region)

gcloud compute addresses describe helloworld-service-internal-ip \
  --region=${REGION} --format='value(address)'

Update the k8s/service.yaml to pin the Load Balancer IP address:

{% code title="k8s/service.yaml" %}

apiVersion: v1
kind: Service
metadata:
  name: helloworld
  annotations:
    cloud.google.com/load-balancer-type: "Internal"
  labels:
    app: helloworld
spec:
  ports:
  - name: 8080-8080
    port: 8080
    protocol: TCP
    targetPort: 8080
  selector:
    app: helloworld
  type: LoadBalancer
  # Replace the value with the IP address you reserved
  loadBalancerIP: RESERVED_IP_ADDRESS

{% endcode %}

Internal HTTP(s) Load Balancer

The setup of the Internal Network Load Balancer is similar to the External HTTP(s) Load Balancer, but with an additional annotation.

Service YAML

In the k8s/service.yaml, use the cloud.google.com/neg annotation to enable Network Endpoint Group (NEG) in order to use container-native load balancing:

{% code title="k8s/service.yaml" %}

apiVersion: v1
kind: Service
metadata:
  name: helloworld
  labels:
    app: helloworld
  # Add the NEG annotation to enable Network Endpoint Group
  # in order to use container-native load balancing
  annotations:
    cloud.google.com/neg: '{"ingress": true}'
spec:
  ports:
  - name: 8080-8080
    port: 8080
    protocol: TCP
    targetPort: 8080
  selector:
    app: helloworld
  type: ClusterIP

{% endcode %}

Ingress YAML

Create a Kubernetes Ingress configuration that will create the HTTP Load Balancer. Create a k8s/ingress.yaml, but also use kubernetes.io/ingress.class annotation to indicate this is an Internal HTTP(s) Load Balancer

{% code title="k8s/ingress.yaml" %}

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: helloworld
  annotations:
    # Add the Ingress Class annotation to use Internal HTTP(s) Load Balancer
    kubernetes.io/ingress.class: "gce-internal"
spec:
  rules:
  - http:
      paths:
      - path: /*
        backend:
          serviceName: helloworld
          servicePort: 8080

{% endcode %}