Deploy Istio Gateway for Prometheus¶

Recall that we deleted the ingress we created for Prometheus. Now, let's enable external access for Prometheus using the Istio Gateway.

Step 1: View Istio Proxy Configuration¶

Note down the current proxy configuration:

# Retrieve proxy configuration
istioctl proxy-config routes svc/istio-ingressgateway -n istio-system

Step 2: Deploy Istio Gateway for Prometheus¶

Prepare istio manifests for Prometheus as follows:

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apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: prometheus-gateway
  namespace: prometheus
spec: 
  selector:
    istio: ingressgateway # use Istio default gateway implementation
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "prometheus.example.com"

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apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: prometheus-virtualservice
  namespace: prometheus
  annotations:
    external-dns.alpha.kubernetes.io/target: "istio-load-balancer-1556246780.ap-south-1.elb.amazonaws.com"
spec: 
  hosts:
  - "prometheus.example.com"
  gateways:
  - prometheus-gateway
  http:
  - match: 
    - uri:   
        prefix: /
    route:
    - destination:
        host: prometheus-server
        port:
          number: 80

Make sure to replace the value of external-dns.alpha.kubernetes.io/target with the load balancer DNS that was created by ingress we created for Istio.

Assuming your folder structure looks like the one below:

|-- manifests
│   |-- prometheus-gateway.yml
│   |-- prometheus-virtualservice.yml

Apply the manifests to deploy the istio gateway for prometheus:

kubectl apply -f manifests/

Step 3: View the Updated Istio Proxy Configuration¶

View the updated proxy configuration:

# Retrieve proxy configuration
istioctl proxy-config routes svc/istio-ingressgateway -n istio-system

Step 4: Verify DNS Record in Route 53¶

Go to AWS Route 53 and verify whether a DNS record was created for the host we defined in the virtual service, pointing to the Istio load balancer.

Step 5: Access Prometheus¶

Open any browser on your local host machine and hit the Prometheus host URL to access prometheus:

https://prometheus.example.com