CODEWITHSUNDEEP
kubernetes
yasin lachini
yasin lachini

Reputation: 6026

How to use DNS in ingress

I deploy an ingress with app1 and app2.

example.com/app1  ---> app1
example.com/app2  ---> app2

And define /etc/hosts in all the machine.

192.168.1.10    example.com

But i want to know in operation how can i use DNS and ingress.

What should i do? What ingress bring to me? I confused by ingress. How should i use it in practical envinroment?

Upvotes: 3

Views: 11283

Answers (3)

Intu
Intu

Reputation: 100

There is an option that can configure your DNS provider automatically - you can install the External-DNS resource. No affiliation, I have simply found it useful.

You will need:

  • A Kubernetes cluster
  • A domain registered with a supported DNS provider
  • The kubectl command-line tool installed and configured

Install and Configure the External-DNS resource

External-DNS installed on your cluster will need to interact with your DNS provider. To configure External-DNS, you'll need to provide extra information regarding your DNS provider via a values.yaml file, as documented here.. First, you need to configure your DNS provider or take note of your DNS provider information. Then, with this information, you can deploy the External-DNS controller in your cluster passing the information via the values.yaml file. You will need to read the documentation of your DNS provider and External-DNS to know what information to provide and in what format, as External-DNS expects different keys and values for different providers. This is an example of how to install using Helm:

#values.yaml
---
provider: aws
aws:
  secretAccessKey:
    secretName: external-dns-aws-credentials
    secretKey: aws_secret_access_key
  accessKeyId:
    secretName: external-dns-aws-credentials
    secretKey: aws_access_key_id

helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update
helm install external-dns bitnami/external-dns -f values.yaml --namespace external-dns --create-namespace

How to use External-DNS

Now that External-DNS is installed and configured, it will automatically create DNS records for Ingress and Service resources with the use of an annotation. For exmaple, to create an Ingress resource use the following annotation to automatically create a DNS record for the specified hostname:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
  external-dns.alpha.kubernetes.io/hostname: my-app.example.com
spec:
  rules:
  - host: my-app.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-app-service
            port:
              number: 80

Here is their cool FAQ.

Upvotes: 1

Rico
Rico

Reputation: 61669

With DNS you can't just use example.com (example.com is owned by IANA). You have to own the DNS configured on your ingress. For example:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: simple-fanout-example
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: mydomain.com
    http:
      paths:
      - path: /foo
        backend:
          serviceName: service1
          servicePort: 4200

In the case above you have to own mydomain.com. You can buy your domain at any major domain registrar like GoDaddy.

Then you will have to expose your Ingress externally depending on the setup you have (AWS, bare-metal, etc) with a LoadBalancer Kubernetes Service and have an A, or CNAME entry on your domain registrar manager, point to that external endpoint (for mydomain.com). For example, on AWS that entry would be a CNAME that looks like this: xxxxx-xxxxxxxxxxxx.us-west-2.elb.amazonaws.com

Note: You can ignore the host altogether but the ingress will only service a default backend as described here with a minimal ingress resource. As far as using your own DNS server, just you can too, as long as your DNS server correctly resolves mydomain.com to the external IP that your ingress controller is fronting.

Hope it helps!

Upvotes: 6

Leandro Donizetti Soares
Leandro Donizetti Soares

Reputation: 492

I deployed a set of 10 or 12 services on K8s and needed a way to expose them to a mobile client. I could create a service of the type loadBalancer for each service, but it would requires to have 10 or more loadBalancers on AWS, all of them pointing to the same set of machines. Instead of that, It was created just one service of type loadBalancer, the ingress service, which depending of the path redirects to the appropriate service. The ingress is used for access outside the cluster, inside you can access using the cluster DNS. For example: my-svc.my-namespace.svc.cluster.local.

Check this link: https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/

And also this one: https://kubernetes.io/docs/concepts/services-networking/ingress/

Upvotes: 0

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