custom-dns-k8s.md

Apply the below yaml file to create sgw-s11 service with static endpoint IPs

kubectl apply -f custom-dns.yaml

Verify DNS resolution

dig @10.96.0.10 sgw-s11.default.svc.cluster.local +short

This should return the two IPs specified in the Endpoints section of the yaml

1.2.3.4
5.6.7.8

Since we are using named ports and specified the protocol in our Service and Endpoint spec, SRV records are automatically populated to discover the port too. E.g.,

dig @10.96.0.10 _s11._udp.sgw-s11.default.svc.cluster.local SRV

Notice the port 2123 under ANSWER SECTION

;; QUESTION SECTION:
;_s11._udp.sgw-s11.default.svc.cluster.local. IN        SRV

;; ANSWER SECTION:
_s11._udp.sgw-s11.default.svc.cluster.local. 30 IN SRV 10 50 2123 cp-0.sgw-s11.default.svc.cluster.local.
_s11._udp.sgw-s11.default.svc.cluster.local. 30 IN SRV 10 50 2123 cp-1.sgw-s11.default.svc.cluster.local.

;; ADDITIONAL SECTION:
cp-0.sgw-s11.default.svc.cluster.local. 30 IN A 1.2.3.4
cp-1.sgw-s11.default.svc.cluster.local. 30 IN A 5.6.7.8

custom-dns.yaml

kind: Service
apiVersion: v1
metadata:
  name: sgw-s11
spec:
  clusterIP: None
  ports:
  - name: s11
    port: 2123
    protocol: UDP
---
kind: Endpoints
apiVersion: v1
metadata:
  name: sgw-s11
subsets:
  - addresses:
      - ip: 1.2.3.4
        hostname: cp-0
      - ip: 5.6.7.8
        hostname: cp-1
    ports:
      - name: s11
        port: 2123
        protocol: UDP