4.1.3 Host based routing in NGINX Ingress Controller (feat. OCI DNS)

See how the Ingress Controller uses OCI DNS for routing based on domain names.

Using OCI DNS service

This is the process of setting up a domain name that has already been purchased. For testing freenom I used the free Domain Name (thekoguryo.ml) issued by the site.

OCI DNS service settings

1. Log in to the OCI console.

2. From the top left hamburger menu, go to Networking > DNS Management > Zones.

3. Click Create Zone

   

4. Enter creation information

   Zone is created based on the domain name used.

   • METHOD: Manual

   • ZONE NAME: Enter your domain name

   • COMPARTMENT: the target Compartment to create

   • ZONE TYPE: Primary

     

5. NS type and SOA type records are created inside Zone. NS is name server record, SOA is permission start record. Click Add Record.

6. Enter and submit the records to be added.

   • Record Type: A - IPv4 Address

   • NAME: *.ingress

     • Enter the subdomain name to be used by the ingress controller in wildcard format.

   • TTL: 300, click the lock on the right to unlock and enter the TTL value

   • RDATA MODE: Basic

   • ADDRESS: IP to be mapped, here, input IP of Load Balancer of nginx ingress controller created earlier

     

7. Click Publish Change to reflect

8. When the confirmation window appears, click Publish Change once more

   

9. Complete Add Record and Reflect

   

10. Copy all name server addresses of type NS in the record.

Set on the domain name provider side

Now you need to set up the domain name on the site where you purchased it. The process below is for setting the freenom standard. Set up in a similar way on the site where you purchased it.

1. Access the freenom site and click Manage Domain to the right of the domain name to be used in My Domain

2. Select Management Tools > Nameservers above, then select Use custom nameservers (enter below).

3. After entering the name server addresses that you copied earlier in OCI DNS Zone, click Change Nameservers

DNS Test

1. Test the DNS registered with the nslookup tool. You can see that it is well registered.

   C:\>nslookup *.ingress.thekoguryo.ml
   Server: kns.kornet.net
   Address: 168.126.63.1
   
   Unauthorized response:
   Name: *.ingress.thekoguryo.ml
   Address: 132.226.225.240
   

HOST based routing test

This is a case where the routing service is different according to the HOST name.

1. Deploy the sample app for testing. Use the same app you used for PATH-based routing.

   Deploy two web pages with different background colors.

   kubectl create deployment nginx-blue --image=thekoguryo/nginx-hello:blue
   kubectl expose deployment nginx-blue --name nginx-blue-svc --port 80
   kubectl create deployment nginx-green --image=thekoguryo/nginx-hello:green
   kubectl expose deployment nginx-green --name nginx-green-svc --port 80
   

2. Write the ingress setup YAML (host-basic.yaml).

   • blue.ingress.thekoguryo.ml requests are routed to nginx-blue-svc
   • green.ingress.thekoguryo.ml requests are routed to nginx-green-svc

   apiVersion: networking.k8s.io/v1
   kind: Ingress
   metadata:
     name: ingress-host-basic
     annotations:
       kubernetes.io/ingress.class: nginx
   spec:
     rules:
     - host: blue.ingress.thekoguryo.ml
       http:
         paths:
         - path: /
           pathType: Prefix
           backend:
             service:
               name: nginx-blue-svc
               port:
                 number: 80
     - host: green.ingress.thekoguryo.ml
       http:
         paths:
         - path: /
           pathType: Prefix
           backend:
             service:
               name: nginx-green-svc
               port:
                 number: 80
   

3. Deploy the created host-basic.yaml.

   $ kubectl apply -f host-basic.yaml 
   ingress.networking.k8s.io/ingress-host-basic created
   $ kubectl get ingress
   NAME                 CLASS    HOSTS                                                    ADDRESS           PORTS   AGE
   ingress-host-basic   <none>   blue.ingress.thekoguryo.ml,green.ingress.thekoguryo.ml                     80      6s
   

4. Connect to each host name applied in the ingress rule and check the result.

   • request blue.ingress.thekoguryo.ml

     

   • request green.ingress.thekoguryo.ml

     

   • You can see that the route is routed to the target service according to the FQDN of the connected host through the Load Balancer of the Ingress Controller registered in DNS with a wildcard address.