chaitanya-pandeswara / kubernetes-nginx-ingress

How To Set Up an Nginx Ingress on DigitalOcean Kubernetes Using Helm.

Table of Contents:

1. Introduction
2. Prerequisites
3. Part-1
   • Step 1 — Setting Up Hello World Deployments
   • Step 2 — Installing the Kubernetes Nginx Ingress Controller
   • Step 3 — Exposing the App Using an Ingress
4. Conclusion
5. Part-2
   • Securing the Ingress Using Cert-Manager

How To Set Up an Nginx Ingress on DigitalOcean Kubernetes Using Helm

Introduction:

Kubernetes Ingresses offer you a flexible way of routing traffic from beyond your cluster to internal Kubernetes Services. Ingress Resources are objects in Kubernetes that define rules for routing HTTP and HTTPS traffic to Services. For these to work, an Ingress Controller must be present; its role is to implement the rules by accepting traffic (most likely via a Load Balancer) and routing it to the appropriate Services. Most Ingress Controllers use only one global Load Balancer for all Ingresses, which is more efficient than creating a Load Balancer per every Service you wish to expose.

Helm is a package manager for managing Kubernetes. Using Helm Charts with your Kubernetes provides configurability and lifecycle management to update, rollback, and delete a Kubernetes application.

In this guide, you’ll set up the Kubernetes-maintained Nginx Ingress Controller using Helm. You’ll then create an Ingress Resource to route traffic from your domains to example Hello World back-end services. Once you’ve set up the Ingress, you’ll install Cert-Manager to your cluster to be able to automatically provision Let’s Encrypt TLS certificates to secure your Ingresses.

Prerequisites:

• A DigitalOcean Kubernetes cluster with your connection configuration configured as thekubectl default. Instructions on how to configure kubectl are shown under the Connect to your Cluster step shown when you create your cluster. To learn how to create a Kubernetes cluster on DigitalOcean, see Kubernetes Quickstart.
• The Helm package manager installed on your local machine, and Tiller installed on your cluster. Complete steps 1 and 2 of the How To Install Software on Kubernetes Clusters with the Helm Package Manager tutorial.
• A fully registered domain name with two available A records. This tutorial will use hw1.your_domain and hw2.your_domain throughout. You can purchase a domain name on Namecheap, get one for free on Freenom, or use the domain registrar of your choice.

Step 1 — Setting Up Hello World Deployments:

In this section, before you deploy the Nginx Ingress, you will deploy a Hello World app called hello-kubernetes to have some Services to which you’ll route the traffic. To confirm that the Nginx Ingress works properly in the next steps, you’ll deploy it twice, each time with a different welcome message that will be shown when you access it from your browser.

You’ll store the deployment configuration on your local machine. The first deployment configuration will be in a file named hello-kubernetes-first.yaml. Create it using a text editor:

nano hello-kubernetes-first.yaml

Add the following lines:

hello-kubernetes-first.yaml

​```
apiVersion: v1
kind: Service
metadata:
  name: hello-kubernetes-first
spec:
  type: ClusterIP
  ports:
  - port: 80
    targetPort: 8080
  selector:
    app: hello-kubernetes-first
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-kubernetes-first
spec:
  replicas: 3
  selector:
    matchLabels:
      app: hello-kubernetes-first
  template:
    metadata:
      labels:
        app: hello-kubernetes-first
    spec:
      containers:
      - name: hello-kubernetes
        image: paulbouwer/hello-kubernetes:1.5
        ports:
        - containerPort: 8080
        env:
        - name: MESSAGE
          value: Hello from the first deployment!
​```

This configuration defines a Deployment and a Service. The Deployment consists of three replicas of the paulbouwer/hello-kubernetes:1.5 image, and an environment variable named MESSAGE—you will see its value when you access the app. The Service here is defined to expose the Deployment in-cluster at port 80.

Save and close the file.

Then, create this first variant of the hello-kubernetes app in Kubernetes by running the following command:

kubectl create -f hello-kubernetes-first.yaml

You’ll see the following output:

Output

service/hello-kubernetes-first created
deployment.apps/hello-kubernetes-first created

To verify the Service’s creation, run the following command:

kubectl get service hello-kubernetes-first

The output will look like this:

Output

NAME                     TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
hello-kubernetes-first   ClusterIP   10.245.85.236   <none>        80:31623/TCP   35s

You’ll see that the newly created Service has a ClusterIP assigned, which means that it is working properly. All traffic sent to it will be forwarded to the selected Deployment on port 8080. Now that you have deployed the first variant of the hello-kubernetes app, you’ll work on the second one.

Open a file called hello-kubernetes-second.yaml for editing:

nano hello-kubernetes-second.yaml

Add the following lines:

hello-kubernetes-second.yaml

apiVersion: v1
kind: Service
metadata:
  name: hello-kubernetes-second
spec:
  type: ClusterIP
  ports:
  - port: 80
    targetPort: 8080
  selector:
    app: hello-kubernetes-second
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-kubernetes-second
spec:
  replicas: 3
  selector:
    matchLabels:
      app: hello-kubernetes-second
  template:
    metadata:
      labels:
        app: hello-kubernetes-second
    spec:
      containers:
      - name: hello-kubernetes
        image: paulbouwer/hello-kubernetes:1.5
        ports:
        - containerPort: 8080
        env:
        - name: MESSAGE
          value: Hello from the second deployment!

Save and close the file.

This variant has the same structure as the previous configuration; the only differences are in the Deployment and Service names, to avoid collisions, and the message.

Now create it in Kubernetes with the following command:

kubectl create -f hello-kubernetes-second.yaml

The output will be:

Output

service/hello-kubernetes-second created
deployment.apps/hello-kubernetes-second created

Verify that the second Service is up and running by listing all of your services:

kubectl get service

The output will be similar to this:

Output

NAME                            TYPE           CLUSTER-IP       EXTERNAL-IP     PORT(S)          AGE
hello-kubernetes-first          ClusterIP      10.245.85.236    <none>          80:31623/TCP     54s
hello-kubernetes-second         ClusterIP      10.245.99.130    <none>          80:30303/TCP     12s
kubernetes                      ClusterIP      10.245.0.1       <none>          443/TCP          5m

Both hello-kubernetes-first and hello-kubernetes-second are listed, which means that Kubernetes has created them successfully.

You’ve created two deployments of the hello-kubernetes app with accompanying Services. Each one has a different message set in the deployment specification, which allow you to differentiate them during testing. In the next step, you’ll install the Nginx Ingress Controller itself.

Step 2 — Installing the Kubernetes Nginx Ingress Controller:

Now you’ll install the Kubernetes-maintained Nginx Ingress Controller using Helm. Note that there are several Nginx Ingresses.

The Nginx Ingress Controller consists of a Pod and a Service. The Pod runs the Controller, which constantly polls the /ingresses endpoint on the API server of your cluster for updates to available Ingress Resources. The Service is of type LoadBalancer, and because you are deploying it to a DigitalOcean Kubernetes cluster, the cluster will automatically create a DigitalOcean Load Balancer, through which all external traffic will flow to the Controller. The Controller will then route the traffic to appropriate Services, as defined in Ingress Resources.

Only the LoadBalancer Service knows the IP address of the automatically created Load Balancer. Some apps (such as ExternalDNS) need to know its IP address, but can only read the configuration of an Ingress. The Controller can be configured to publish the IP address on each Ingress by setting the controller.publishService.enabled parameter to true during helm install. It is recommended to enable this setting to support applications that may depend on the IP address of the Load Balancer.

To install the Nginx Ingress Controller to your cluster, run the following command:

helm install stable/nginx-ingress --name nginx-ingress --set controller.publishService.enabled=true

This command installs the Nginx Ingress Controller from the stable charts repository, names the Helm release nginx-ingress, and sets the publishService parameter to true.

The output will look like:

Output

NAME:   nginx-ingress
LAST DEPLOYED: ...
NAMESPACE: default
STATUS: DEPLOYED

RESOURCES:
==> v1/ConfigMap
NAME                      DATA  AGE
nginx-ingress-controller  1     0s

==> v1/Pod(related)
NAME                                            READY  STATUS             RESTARTS  AGE
nginx-ingress-controller-7658988787-npv28       0/1    ContainerCreating  0         0s
nginx-ingress-default-backend-7f5d59d759-26xq2  0/1    ContainerCreating  0         0s

==> v1/Service
NAME                           TYPE          CLUSTER-IP     EXTERNAL-IP  PORT(S)                     AGE
nginx-ingress-controller       LoadBalancer  10.245.9.107   <pending>    80:31305/TCP,443:30519/TCP  0s
nginx-ingress-default-backend  ClusterIP     10.245.221.49  <none>       80/TCP                      0s

==> v1/ServiceAccount
NAME           SECRETS  AGE
nginx-ingress  1        0s

==> v1beta1/ClusterRole
NAME           AGE
nginx-ingress  0s

==> v1beta1/ClusterRoleBinding
NAME           AGE
nginx-ingress  0s

==> v1beta1/Deployment
NAME                           READY  UP-TO-DATE  AVAILABLE  AGE
nginx-ingress-controller       0/1    1           0          0s
nginx-ingress-default-backend  0/1    1           0          0s

==> v1beta1/Role
NAME           AGE
nginx-ingress  0s

==> v1beta1/RoleBinding
NAME           AGE
nginx-ingress  0s

NOTES:
...

Helm has logged what resources in Kubernetes it created as a part of the chart installation.

You can watch the Load Balancer become available by running:

kubectl get services -o wide -w nginx-ingress-controller

You’ve installed the Nginx Ingress maintained by the Kubernetes community. It will route HTTP and HTTPS traffic from the Load Balancer to appropriate back-end Services, configured in Ingress Resources. In the next step, you’ll expose the hello-kubernetes app deployments using an Ingress Resource.

Step 3 — Exposing the App Using an Ingress:

Now you’re going to create an Ingress Resource and use it to expose the hello-kubernetes app deployments at your desired domains. You’ll then test it by accessing it from your browser.

You’ll store the Ingress in a file named hello-kubernetes-ingress.yaml. Create it using your editor:

nano hello-kubernetes-ingress.yaml

Add the following lines to your file:

hello-kubernetes-ingress.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: hello-kubernetes-ingress
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  rules:
  - host: hw1.your_domain
    http:
      paths:
      - backend:
          serviceName: hello-kubernetes-first
          servicePort: 80
  - host: hw2.your_domain
    http:
      paths:
      - backend:
          serviceName: hello-kubernetes-second
          servicePort: 80

In the code above, you define an Ingress Resource with the name hello-kubernetes-ingress. Then, you specify two host rules, so that hw1.your_domain is routed to the hello-kubernetes-first Service, and hw2.your_domain is routed to the Service from the second deployment (hello-kubernetes-second).

Remember to replace the highlighted domains with your own, then save and close the file.

Create it in Kubernetes by running the following command:

kubectl create -f hello-kubernetes-ingress.yaml

Next, you’ll need to ensure that your two domains are pointed to the Load Balancer via A records. This is done through your DNS provider. To configure your DNS records on DigitalOcean, see How to Manage DNS Records.

You can now navigate to hw1.your_domain in your browser. You will see the following:

The second variant (hw2.your_domain) will show a different message:

With this, you have verified that the Ingress Controller correctly routes requests; in this case, from your two domains to two different Services.

You’ve created and configured an Ingress Resource to serve the hello-kubernetes app deployments at your domains. In the next step, you’ll set up Cert-Manager, so you’ll be able to secure your Ingress Resources with free TLS certificates from Let’s Encrypt.

Conclusion:

You have now successfully set up the Nginx Ingress Controller and Cert-Manager on your DigitalOcean Kubernetes cluster using Helm. You are now able to expose your apps to the Internet, at your domains, secured using Let’s Encrypt TLS certificates.

For further information about the Helm package manager, read this introduction article.

Securing the Ingress Using Cert-Manager

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