Deploy Nginx Ingress Controller on Kubernetes using Helm Chart

Deploy Nginx Ingress Controller on Kubernetes. The standard way of exposing applications that are running on a set of Pods in a Kubernetes Cluster is by using service resource. Each Pod in Kubernetes has its own IP address, but a set of Pods can have a single DNS name. Kubernetes is able to load-balance traffic across the Pods without any modification in the application layer. A service, by default is assigned an IP address (sometimes called the “cluster IP“), which is used by the Service proxies. A Service is able to identify a set of Pods using label selectors.

What is an Ingress Controller?

Before you can answer this question, an understanding of Ingress object in Kubernetes is important. From the official Kubernetes documentation, an Ingress is defined like as:

An API object that manages external access to the services in a cluster, typically HTTP.

Ingress may provide load balancing, SSL termination and name-based virtual hosting.

An Ingress in Kubernetes exposes HTTP and HTTPS routes from outside the cluster to services running within the cluster. All the traffic routing is controlled by rules defined on the Ingress resource. An Ingress may be configured to:

Provide Services with externally-reachable URLs
Load balance traffic coming into cluster services
Terminate SSL / TLS traffic
Provide name-based virtual hosting in Kubernetes

An Ingress controller is what fulfils the Ingress, usually with a load balancer. Below is an example on how an Ingress sends all the client traffic to a Service in Kubernetes Cluster:

For the standard HTTP and HTTPS traffic, an Ingress Controller will be configured to listen on ports 80 and 443. It should bind to an IP address from which the cluster will receive traffic from. A Wildcard DNS record for the domain used for Ingress routes will point to the IP address(s) that Ingress controller listens on.

It is fact that Kubernetes adopts a BYOS (Bring-Your-Own-Software) approach to most of its addons and it doesn’t provide a software that does Ingress functions out of the box. You can choose from the plenty of Ingress Controllers available. Kubedex does a good job as well on summarizing list of Ingresses available for Kubernetes.

With all the basics on Kubernetes Services and Ingress, we can now plunge into the actual installation of NGINX Ingress Controller Kubernetes.

Step 1: Deploy Nginx Ingress Controller in Kubernetes

We shall consider two major deployment options captured in the next sections.

Option 1: Install without Helm

With this method you’ll manually download and run deployment manifests using kubectl command line tool.

Step 1: Install git, curl and wget tools

Install git, curl and wget tools in your Bastion where kubectl is installed and configured:

# CentOS / RHEL / Fedora / Rocky
sudo yum -y install wget curl git

# Debian / Ubuntu
sudo apt update
sudo apt install wget curl git

Step 2: Apply Nginx Ingress Controller manifest

The deployment process varies depending on your Kubernetes setup. My Kubernetes will use Bare-metal Nginx Ingress deployment guide. For other Kubernetes clusters including managed clusters refer to below guides:

The Bare-metal method applies to any Kubernetes clusters deployed on bare-metal with generic Linux distribution(Such as CentOS, Ubuntu, Debian, Rocky Linux) e.t.c.

Download Nginx controller deployment for Baremetal:

controller_tag=$(curl -s https://api.github.com/repos/kubernetes/ingress-nginx/releases/latest | grep tag_name | cut -d '"' -f 4)
wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/${controller_tag}/deploy/static/provider/baremetal/deploy.yaml

Rename deployment file:

mv deploy.yaml nginx-ingress-controller-deploy.yaml

Feel free to check the file contents and modify where you see fit:

vim nginx-ingress-controller-deploy.yaml

Apply Nginx ingress controller manifest deployment file:

$ kubectl apply -f nginx-ingress-controller-deploy.yaml
namespace/ingress-nginx created
serviceaccount/ingress-nginx created
configmap/ingress-nginx-controller created
clusterrole.rbac.authorization.k8s.io/ingress-nginx created
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx created
role.rbac.authorization.k8s.io/ingress-nginx created
rolebinding.rbac.authorization.k8s.io/ingress-nginx created
service/ingress-nginx-controller-admission created
service/ingress-nginx-controller created
deployment.apps/ingress-nginx-controller created
ingressclass.networking.k8s.io/nginx created
validatingwebhookconfiguration.admissionregistration.k8s.io/ingress-nginx-admission created
serviceaccount/ingress-nginx-admission created
clusterrole.rbac.authorization.k8s.io/ingress-nginx-admission created
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx-admission created
role.rbac.authorization.k8s.io/ingress-nginx-admission created
rolebinding.rbac.authorization.k8s.io/ingress-nginx-admission created
job.batch/ingress-nginx-admission-create created
job.batch/ingress-nginx-admission-patch created

You can update your current context to use nginx ingress namespace:

kubectl config set-context --current --namespace=ingress-nginx

Run the following command to check if the ingress controller pods have started:

$ kubectl get pods -n ingress-nginx -l app.kubernetes.io/name=ingress-nginx --watch
NAME                                        READY   STATUS      RESTARTS   AGE
ingress-nginx-admission-create--1-hpkzp     0/1     Completed   0          43s
ingress-nginx-admission-patch--1-qnjlj      0/1     Completed   1          43s
ingress-nginx-controller-644555766d-snvqf   1/1     Running     0

Once the ingress controller pods are running, you can cancel the command typing Ctrl+C.

If you want to run multiple Nginx Ingress Pods, you can scale with the command below:

$ kubectl -n ingress-nginx scale deployment ingress-nginx-controller --replicas 2
deployment.apps/ingress-nginx-controller scaled

$ kubectl get pods  -n ingress-nginx
NAME                                        READY   STATUS              RESTARTS   AGE
ingress-nginx-admission-create-lj278        0/1     Completed           0          18m
ingress-nginx-admission-patch-zsjkp         0/1     Completed           0          18m
ingress-nginx-controller-6dc865cd86-n474n   0/1     ContainerCreating   0          119s
ingress-nginx-controller-6dc865cd86-tmlgf   1/1     Running             0          18m

Option 2: Install using Helm

If you opt in for the Helm installation method then follow the steps provided in this section.

Step 1: Install helm 3 in our workstation

Install helm 3 in your Workstation where Kubectl is installed and configured.

cd ~/
curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3
chmod 700 get_helm.sh
./get_helm.sh

The installer script works for both Linux and macOS operating systems. Here is a successful installation output:

Downloading https://get.helm.sh/helm-v3.10.3-linux-amd64.tar.gz
Verifying checksum... Done.
Preparing to install helm into /usr/local/bin
helm installed into /usr/local/bin/helm

Let’s query for helm package version to validate working installation:

$ helm version
version.BuildInfo{Version:"v3.10.3", GitCommit:"835b7334cfe2e5e27870ab3ed4135f136eecc704", GitTreeState:"clean", GoVersion:"go1.18.9"}

Step 2: Deploy Nginx Ingress Controller

Download latest stable release of Nginx Ingress Controller code:

controller_tag=$(curl -s https://api.github.com/repos/kubernetes/ingress-nginx/releases/latest | grep tag_name | cut -d '"' -f 4)
wget https://github.com/kubernetes/ingress-nginx/archive/refs/tags/${controller_tag}.tar.gz

Extract the file downloaded:

tar xvf ${controller_tag}.tar.gz

Switch to the directory created:

cd ingress-nginx-${controller_tag}

Change your working directory to charts folder:

cd charts/ingress-nginx/

Create namespace

kubectl create namespace ingress-nginx

Now deploy Nginx Ingress Controller using the following commands

helm install -n ingress-nginx ingress-nginx  -f values.yaml .

Sample deployment output

NAME: ingress-nginx
LAST DEPLOYED: Thu Nov  4 02:50:28 2021
NAMESPACE: ingress-nginx
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
The ingress-nginx controller has been installed.
It may take a few minutes for the LoadBalancer IP to be available.
You can watch the status by running 'kubectl --namespace ingress-nginx get services -o wide -w ingress-nginx-controller'

An example Ingress that makes use of the controller:

  apiVersion: networking.k8s.io/v1
  kind: Ingress
  metadata:
    annotations:
      kubernetes.io/ingress.class: nginx
    name: example
    namespace: foo
  spec:
    ingressClassName: example-class
    rules:
      - host: www.example.com
        http:
          paths:
            - path: /
              pathType: Prefix
              backend:
                service:
                  name: exampleService
                  port: 80
    # This section is only required if TLS is to be enabled for the Ingress
    tls:
      - hosts:
        - www.example.com
        secretName: example-tls

If TLS is enabled for the Ingress, a Secret containing the certificate and key must also be provided:

  apiVersion: v1
  kind: Secret
  metadata:
    name: example-tls
    namespace: foo
  data:
    tls.crt: <base64 encoded cert>
    tls.key: <base64 encoded key>
  type: kubernetes.io/tls

Check status of all resources in ingress-nginx namespace:

kubectl get all -n ingress-nginx

Checking runningPods in the namespace.

$ kubectl get pods -n ingress-nginx
NAME                                        READY   STATUS    RESTARTS   AGE
ingress-nginx-controller-6f5844d579-hwrqn   1/1     Running   0

To check logs in the Pods use the commands:

$ kubectl -n ingress-nginx  logs deploy/ingress-nginx-controller
-------------------------------------------------------------------------------
NGINX Ingress controller
  Release:       v1.0.4
  Build:         9b78b6c197b48116243922170875af4aa752ee59
  Repository:    https://github.com/kubernetes/ingress-nginx
  nginx version: nginx/1.19.9

-------------------------------------------------------------------------------

W1104 00:06:59.684972       7 client_config.go:615] Neither --kubeconfig nor --master was specified.  Using the inClusterConfig.  This might not work.
I1104 00:06:59.685080       7 main.go:221] "Creating API client" host="https://10.96.0.1:443"
I1104 00:06:59.694832       7 main.go:265] "Running in Kubernetes cluster" major="1" minor="22" git="v1.22.2" state="clean" commit="8b5a19147530eaac9476b0ab82980b4088bbc1b2" platform="linux/amd64"
I1104 00:06:59.937097       7 main.go:104] "SSL fake certificate created" file="/etc/ingress-controller/ssl/default-fake-certificate.pem"
I1104 00:06:59.956498       7 ssl.go:531] "loading tls certificate" path="/usr/local/certificates/cert" key="/usr/local/certificates/key"
I1104 00:06:59.975510       7 nginx.go:253] "Starting NGINX Ingress controller"
I1104 00:07:00.000753       7 event.go:282] Event(v1.ObjectReference{Kind:"ConfigMap", Namespace:"ingress-nginx", Name:"ingress-nginx-controller", UID:"5aea2f36-fdf2-4f5c-96ff-6a5cbb0b5b82", APIVersion:"v1", ResourceVersion:"13359975", FieldPath:""}): type: 'Normal' reason: 'CREATE' ConfigMap ingress-nginx/ingress-nginx-controller
I1104 00:07:01.177639       7 nginx.go:295] "Starting NGINX process"
I1104 00:07:01.177975       7 leaderelection.go:243] attempting to acquire leader lease ingress-nginx/ingress-controller-leader...
I1104 00:07:01.178194       7 nginx.go:315] "Starting validation webhook" address=":8443" certPath="/usr/local/certificates/cert" keyPath="/usr/local/certificates/key"
I1104 00:07:01.180652       7 controller.go:152] "Configuration changes detected, backend reload required"
I1104 00:07:01.197509       7 leaderelection.go:253] successfully acquired lease ingress-nginx/ingress-controller-leader
I1104 00:07:01.197857       7 status.go:84] "New leader elected" identity="ingress-nginx-controller-6f5844d579-hwrqn"
I1104 00:07:01.249690       7 controller.go:169] "Backend successfully reloaded"
I1104 00:07:01.249751       7 controller.go:180] "Initial sync, sleeping for 1 second"
I1104 00:07:01.249999       7 event.go:282] Event(v1.ObjectReference{Kind:"Pod", Namespace:"ingress-nginx", Name:"ingress-nginx-controller-6f5844d579-hwrqn", UID:"d6a2e95f-eaaa-4d6a-85e2-bcd25bf9b9a3", APIVersion:"v1", ResourceVersion:"13364867", FieldPath:""}): type: 'Normal' reason: 'RELOAD' NGINX reload triggered due to a change in configuration

To follow logs as they stream run:

kubectl -n ingress-nginx  logs deploy/ingress-nginx-controller -f

Upgrading Helm Release

I’ll set replica count of the controller Pods to 2:

$ vim values.yaml 
controller:
  replicaCount: 3

We can confirm we currently have one Pod:

$ kubectl -n ingress-nginx  get deploy
NAME                       READY   UP-TO-DATE   AVAILABLE   AGE
ingress-nginx-controller   1/1     1            1           43m

Upgrade ingress-nginx release by running the following helm commands:

$ helm upgrade -n ingress-nginx ingress-nginx -f values.yaml .
Release "ingress-nginx" has been upgraded. Happy Helming!
NAME: ingress-nginx
LAST DEPLOYED: Thu Nov  4 03:35:41 2021
NAMESPACE: ingress-nginx
STATUS: deployed
REVISION: 5
TEST SUITE: None
NOTES:
The ingress-nginx controller has been installed.

Check current number of pods after the upgrade:

$ kubectl -n ingress-nginx  get deploy
NAME                       READY   UP-TO-DATE   AVAILABLE   AGE
ingress-nginx-controller   3/3     3            3           45m

Uninstalling the Chart

To remove nginx ingress controller and all its associated resources that we deployed by Helm execute below command in your terminal.

$ helm -n ingress-nginx uninstall ingress-nginx
release "ingress-nginx" uninstalled

Step 2: Configure Nginx Ingress Controller on Kubernetes

With Ingress Controller installed, we need to configure external connectivity method. For this we have two major options.

Option 1: Using Load Balancer (Highly recommended)

Load balancer is used to expose an application running in Kubernetes cluster to the external network. It provides a single IP address to route incoming requests to Ingress controller application. In order to successfully create Kubernetes services of type LoadBalancer, you need to have the load balancer implementation inside / or outside Kubernetes.

When a service is deployed in cloud environment, Load Balancer will be available to your service by default. Ingress service should get the LB IP address automatically. But for Baremetal installations you’ll need to deploy Load Balancer implementation for Kubernetes, we recommend MetalLB, use guide in link below to install it.

1. Setting Nginx Ingress to use MetalLB

Check Nginx Ingress service.

$ kubectl get svc -n ingress-nginx
NAME                                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx-controller             NodePort    10.108.4.75      <none>        80:30084/TCP,443:30540/TCP   5m55s
ingress-nginx-controller-admission   ClusterIP   10.105.200.185   <none>        443/TCP                      5m55s

If your Kubernetes cluster is a “real” cluster that supports services of type LoadBalancer, it will have allocated an external IP address or FQDN to the ingress controller.

Use the following command to see that IP address or FQDN:

$ kubectl get service ingress-nginx-controller --namespace=ingress-nginx
NAME                       TYPE       CLUSTER-IP    EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx-controller   NodePort   10.108.4.75   <none>        80:30084/TCP,443:30540/TCP   7m53s

Patch ingress-nginx-controller service by setting service type to LoadBalancer.

kubectl -n ingress-nginx patch svc ingress-nginx-controller --type='json' -p '[{"op":"replace","path":"/spec/type","value":"LoadBalancer"}]'

Confirm successful patch of the service.

service/ingress-nginx-controller patched

Service is assigned an IP address automatically from Address Pool as configured in MetalLB.

$ kubectl get service ingress-nginx-controller --namespace=ingress-nginx
NAME                       TYPE           CLUSTER-IP    EXTERNAL-IP    PORT(S)                      AGE
ingress-nginx-controller   LoadBalancer   10.108.4.75   192.168.1.30   80:30084/TCP,443:30540/TCP   10m

2. Mapping DNS name for Nginx Ingresses to LB IP

We can create domain name, preferably wildcard for use when creating Ingress routes in Kubernetes. In our cluster, we have k8s.example.com as base domain. We’ll use a unique wildcard domain *.k8s.example.com for Ingress.

The mapping is *.k8s.example.com pointing to IP address *192.168.1.30* **(Nginx Ingress LB IP)**.

Option 2: Using Specific Nodes to run Nginx Ingress Pods (NOT recommended)

This is not recommended implementation and exists to serve as reference documentation.

1. Label nodes that will run Ingress Controller Pods

The node selector is used when we have to deploy a pod or group of pods on a specific group of nodes that passed the criteria defined in the configuration file.

List nodes:

$ kubectl get nodes
NAME                         STATUS   ROLES                  AGE   VERSION
k8smaster01.example.com      Ready    control-plane,master   14h   v1.23.5
k8smaster02.example.com      Ready    control-plane,master   14h   v1.23.5
k8sworker01.example.com      Ready    <none>                 13h   v1.23.5
k8sworker02.example.com      Ready    <none>                 13h   v1.23.5
k8sworker03.example.com      Ready    <none>                 13h   v1.23.5

2. Edit ingress-nginx-controller service and set externalIPs

In a private Infrastructure Kubernetes deployment setup it is unlikely that you’ll have Load Balancer service support.

$ kubectl get svc  -n ingress-nginx ingress-nginx-controller
NAME                       TYPE       CLUSTER-IP    EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx-controller   NodePort   10.101.4.21   <none>        80:30248/TCP,443:30773/TCP   3m53s

You’ll notice the service of NodePort type. We’ll update the service by making Ingress bind to specific IP address by using External IPs.

Kubernetes supports assignment of external IP addresses to a Service spec.externalIPs field through the ExternalIP facility. This will expose an additional virtual IP address, assigned to Nginx Ingress Controller Service. This allows us to direct traffic to a local node for load balancing.

In my Kubernetes Cluster I have two control Plane nodes with below primary IP addresses:

k8smaster01.example.com – 192.168.42.245
k8smaster02.example.com – 192.168.42.246

IP addresses of the nodes can be checked by running the command:

kubectl get nodes -o wide

I’ll create a file containing modification to add External IPs to the service.

$ vim external-ips.yaml
spec:
  externalIPs:
  - 192.168.42.245
  - 192.168.42.246

Let’s now apply the patch to the service.

$ kubectl -n ingress-nginx patch svc ingress-nginx-controller --patch "$(cat external-ips.yaml)"
service/ingress-nginx-controller patched

Check service after applying the patch if External IPs are added:

$ kubectl get svc  ingress-nginx-controller -n ingress-nginx
NAME                       TYPE       CLUSTER-IP    EXTERNAL-IP                     PORT(S)                      AGE
ingress-nginx-controller   NodePort   10.101.4.21   192.168.42.245,192.168.42.246   80:30248/TCP,443:30773/TCP   8m31

3. Running ingress-nginx-controller Pods on Control Plane (Master) Nodes

You can consider running Ingress Controller Pods on the master nodes. To achieve this, we’ll label the master nodes then use node selector to assign pods in Ingress controller deployment to Control Plane nodes.

$ kubectl get nodes -l node-role.kubernetes.io/control-plane
NAME                         STATUS   ROLES                  AGE   VERSION
k8smaster01.example.com      Ready    control-plane,master   16d   v1.23.5
k8smaster02.example.com      Ready    control-plane,master   16d   v1.23.5

Add labels runingress=nginx to the master nodes; thing can be any other nodes in the cluster:

kubectl label node k8smaster01.example.com runingress=nginx
kubectl label node k8smaster02.example.com runingress=nginx

Labels added to a node can be checked using the command:

kubectl describe node <node-name>

Example:

$ kubectl describe node k8smaster01.example.com
Name:               k8smaster01.example.com
Roles:              control-plane,master
Labels:             beta.kubernetes.io/arch=amd64
                    beta.kubernetes.io/os=linux
                    kubernetes.io/arch=amd64
                    kubernetes.io/hostname=k8smaster01.example.com
                    kubernetes.io/os=linux
                    node-role.kubernetes.io/control-plane=
                    node-role.kubernetes.io/master=
                    node.kubernetes.io/exclude-from-external-load-balancers=
                    runingress=nginx # Label added
.....

Create patch file to run the Pods in nodes with label runingress=nginx

$ vim node-selector-patch.yaml
spec:
  template:
    spec:
      nodeSelector:
        runingress: nginx

Apply the patch to add node selector:

$ kubectl get deploy  -n ingress-nginx
NAME                       READY   UP-TO-DATE   AVAILABLE   AGE
ingress-nginx-controller   1/1     1            1           20m

$ kubectl -n ingress-nginx patch deployment/ingress-nginx-controller --patch "$(cat node-selector-patch.yaml)"
deployment.apps/ingress-nginx-controller patched

4. Add tolerations to allow Nginx ingress Pods to run in Control Plane nodes

In Kubernetes the default setting is to disable pods from running in the master nodes. To have Ingress pods run in the master nodes, you’ll have to add tolerations.

Let’s create a patch file to apply tolerations on Ingress deployment.

$ vim master-node-tolerations.yaml
spec:
  template:
    spec:
      tolerations:
        - key: node-role.kubernetes.io/master
          operator: Equal
          value: "true"
          effect: NoSchedule
        - key: node-role.kubernetes.io/master
          operator: Equal
          effect: NoSchedule
        - key: node-role.kubernetes.io/control-plane
          operator: Equal
          value: "true"
          effect: NoSchedule
        - key: node-role.kubernetes.io/control-plane
          operator: Equal
          effect: NoSchedule

Apply the patch:

kubectl -n ingress-nginx patch deployment/ingress-nginx-controller --patch "$(cat master-node-tolerations.yaml)"

Confirm the new pod created has Node Selector configured.

$ kubectl get pods -n ingress-nginx
NAME                                        READY   STATUS      RESTARTS   AGE
ingress-nginx-admission-create--1-hpkzp     0/1     Completed   0          3d
ingress-nginx-admission-patch--1-qnjlj      0/1     Completed   1          3d
ingress-nginx-controller-57b46c846b-8n28t   1/1     Running     0          1m47s

$ kubectl describe pod ingress-nginx-controller-57b46c846b-8n28t
...omitted_output...
QoS Class:                   Burstable
Node-Selectors:              kubernetes.io/os=linux
                             run-nginx-ingress=true
                             runingress=nginx
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type    Reason     Age   From                      Message
  ----    ------     ----  ----                      -------
.....

5. Updating values.yml file to change parameters (only when using Helm deployment)

Edit values file

vim values.yaml

Add tolerations for Master nodes

controller:
  tolerations:
    - key: node-role.kubernetes.io/master
      operator: Equal
      value: "true"
      effect: NoSchedule
    - key: node-role.kubernetes.io/master
      operator: Equal
      effect: NoSchedule
    - key: node-role.kubernetes.io/control-plane
      operator: Equal
      value: "true"
      effect: NoSchedule
    - key: node-role.kubernetes.io/control-plane
      operator: Equal
      effect: NoSchedule

Setcontroller.service.externalIPs

controller:
  service:
    externalIPs: ["192.168.42.245","192.168.42.246"]

To set number of replicas of the Ingress controller deployment on controller.replicaCount

controller:
  replicaCount: 1

If using node selector for pod assignment for the Ingress controller pods set on controller.nodeSelector

controller:
  nodeSelector:
    kubernetes.io/os: linux
    runingress: "nginx"

Create namespace

kubectl create namespace ingress-nginx

Now deploy Nginx Ingress Controller using the following commands

helm install -n ingress-nginx ingress-nginx  -f values.yaml .

Step 3: Deploy Services to test Nginx Ingress functionality

Create a temporary namespace called demo

kubectl create namespace demo

Create test Pods and Services YAML file:

cd ~/
vim demo-app.yml

Paste below data into the file:

kind: Pod
apiVersion: v1
metadata:
  name: apple-app
  labels:
    app: apple
spec:
  containers:
    - name: apple-app
      image: hashicorp/http-echo
      args:
        - "-text=apple"
---

kind: Service
apiVersion: v1
metadata:
  name: apple-service
spec:
  selector:
    app: apple
  ports:
    - port: 5678 # Default port for image
---
kind: Pod
apiVersion: v1
metadata:
  name: banana-app
  labels:
    app: banana
spec:
  containers:
    - name: banana-app
      image: hashicorp/http-echo
      args:
        - "-text=banana"
---

kind: Service
apiVersion: v1
metadata:
  name: banana-service
spec:
  selector:
    app: banana
  ports:
    - port: 5678 # Default port for image

Create pod and service objects:

$ kubectl apply -f demo-app.yml -n demo
pod/apple-app created
service/apple-service created
pod/banana-app created
service/banana-service created

Test if it is working

$ kubectl get pods -n demo
NAME         READY   STATUS    RESTARTS   AGE
apple-app    1/1     Running   0          2m53s
banana-app   1/1     Running   0          2m52s

$ kubectl -n demo logs apple-app
2022/09/03 23:21:19 Server is listening on :5678

Create Ubuntu pod that will be used to test service connection.

cat <<EOF | kubectl -n demo apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: ubuntu
  labels:
    app: ubuntu
spec:
  containers:
  - name: ubuntu
    image: ubuntu:latest
    command: ["/bin/sleep", "3650d"]
    imagePullPolicy: IfNotPresent
  restartPolicy: Always
EOF

Test services connectivity within the namespace.

$ kubectl -n demo exec -ti ubuntu -- bash
root@ubuntu:/# apt update && apt install curl -y
root@ubuntu:/# curl apple-service:5678
apple
root@ubuntu:/# curl banana-service:5678
banana

Creating an ingress route

The Ingress definition method can also be viewed using explain command option:

$ kubectl explain ingress
KIND:     Ingress
VERSION:  networking.k8s.io/v1

DESCRIPTION:
     Ingress is a collection of rules that allow inbound connections to reach
     the endpoints defined by a backend. An Ingress can be configured to give
     services externally-reachable urls, load balance traffic, terminate SSL,
     offer name based virtual hosting etc.

FIELDS:
   apiVersion	<string>
     APIVersion defines the versioned schema of this representation of an
     object. Servers should convert recognized schemas to the latest internal
     value, and may reject unrecognized values. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources

   kind	<string>
     Kind is a string value representing the REST resource this object
     represents. Servers may infer this from the endpoint the client submits
     requests to. Cannot be updated. In CamelCase. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds

   metadata	<Object>
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata

   spec	<Object>
     Spec is the desired state of the Ingress. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status

   status	<Object>
     Status is the current state of the Ingress. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status

Now, declare an Ingress to route requests to /apple to the first service, and requests to /banana to second service. Check out the Ingress’ rules field that declares how requests are passed along.

vim webapp-app-ingress.yml

For Kubernetes cluster version >= 1.19:

---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: webapp-ingress
spec:
  ingressClassName: nginx
  rules:
  - host: webapp.k8s.example.com
    http:
      paths:
        - path: /
          pathType: Prefix
          backend:
            service:
              name: web-server-service
              port:
                number: 80

Then apply file to create the objects

$ kubectl -n web apply -f  webapp-app-ingress.yml
ingress.networking.k8s.io/webapp-ingress created

List configured ingress:

$ kubectl get ingress -n web
NAME             CLASS   HOSTS                            ADDRESS   PORTS   AGE
webapp-ingress   nginx   webapp.k8s.example.com                     80      7s

Enter nginx ingress controller to check whether nginx configuration if injected

$ kubectl get pods -n ingress-nginx
NAME                                        READY   STATUS    RESTARTS   AGE
ingress-nginx-controller-6f5844d579-hwrqn   1/1     Running   0          53m
ingress-nginx-controller-6f5844d579-kvgtd   1/1     Running   0          25m
ingress-nginx-controller-6f5844d579-lcrrt   1/1     Running   0          25m

$ kubectl exec -n ingress-nginx  -it ingress-nginx-controller-6f5844d579-hwrqn  -- /bin/bash
bash-5.1$ less /etc/nginx/nginx.conf

Test service using curl.

$ curl http://webapp.k8s.example.com/
<html><body><h1>It works!</h1></body></html>

That’s it!