What Are the Steps to Create a Custom Istio Ingress Gateway Controller in Kubernetes?

Creating a custom Istio Ingress Gateway Controller in Kubernetes has some clear steps. These steps help us manage our ingress traffic better for our applications. This process improves our Kubernetes setup. It gives us more control over how we route traffic, set security rules, and balance loads. To set up a custom Istio Ingress Gateway, we need to follow a clear plan. This plan includes checking what we need first, preparing our environment, setting up custom resources, and launching the controller.

In this article, we will talk about the important steps to create a custom Istio Ingress Gateway Controller in Kubernetes. We will look at these topics:

What we need for a custom Istio Ingress Gateway Controller
How to set up our Kubernetes environment for the Istio Ingress Gateway
How to set up Istio Ingress Gateway custom resources
How to launch our custom Istio Ingress Gateway Controller
How to test our custom Istio Ingress Gateway Controller
Common questions about Istio Ingress Gateway Controllers

By following these steps, we will understand how to use Istio’s strong features in our Kubernetes setup.

Understanding the Prerequisites for Custom Istio Ingress Gateway Controller

Before we create a custom Istio Ingress Gateway Controller in Kubernetes, we need to make sure we have these things ready:

Kubernetes Cluster: We need a working Kubernetes cluster. We can set one up using Minikube or services like AWS EKS, GKE, or AKS. For help, check out how to set up a Kubernetes cluster on AWS EKS.
Istio Installation: We must have Istio installed in our Kubernetes environment. We can follow the guide in how to install and configure Istio to do this.
kubectl: Make sure we have kubectl installed. It should be set up to connect with our Kubernetes cluster.
Custom Resource Definitions (CRDs): We should know about Istio’s CRDs. This knowledge helps us define custom settings for our Ingress Gateway.
Namespace Configuration: We need to choose a namespace for our custom Ingress Gateway. We should also set all necessary permissions and settings for that namespace.
Service Account: We have to create a service account with permissions to manage Istio resources. We can use this command:
```
kubectl create serviceaccount <service-account-name> -n <namespace>
```

Cluster Role Binding: We must link the service account to a cluster role. This allows it to manage Istio resources:

kubectl create clusterrolebinding <binding-name> --clusterrole=edit --serviceaccount=<namespace>:<service-account-name>

Networking Knowledge: It is good to have basic knowledge of Kubernetes networking and how Istio manages traffic.
Resource Quotas: We should check if our Kubernetes cluster has resource limits that might affect how we deploy our custom Ingress Gateway.
Access to Container Registry: We need access to a container registry if we want to build and use a custom image for our Ingress Gateway Controller.

When we complete these prerequisites, we will be ready to create and set up a custom Istio Ingress Gateway Controller in our Kubernetes environment.

Setting Up Your Kubernetes Environment for Custom Istio Ingress Gateway

To make a custom Istio Ingress Gateway Controller in Kubernetes, we first need to set up our Kubernetes environment. This means we must have the right tools and settings to install Istio and manage Ingress traffic well.

Prerequisites

Kubernetes Cluster: We need a running Kubernetes cluster. We can use Minikube, GKE, EKS, or AKS. Follow the guides to set up your cluster:
- How do I install Minikube for local Kubernetes development
- How do I set up a Kubernetes cluster on AWS EKS
Kubectl: We install kubectl, which is the command-line tool for Kubernetes. We must make sure it works with our cluster.
```
kubectl version --client
```

Istio: We need to download and install Istio on our Kubernetes cluster. Use these commands to install Istio:

curl -L https://istio.io/downloadIstio | sh -
cd istio-<version>
export PATH=$PWD/bin:$PATH
istioctl install --set profile=demo -y

Enable Ingress: We must enable the Istio ingress gateway. We can check its status using:
```
kubectl get svc -n istio-system
```
Networking: We need to set up our Kubernetes network settings. This will let traffic go through the Istio ingress gateway.

Configuring Your Environment

Namespace Creation: We create a namespace for our apps and the Istio ingress gateway.
```
kubectl create namespace my-app
```
Labeling Namespace: We label our namespace to allow Istio injection.
```
kubectl label namespace my-app istio-injection=enabled
```

Install Required Resources: We deploy any needed resources or services for our apps. For example, if we deploy a sample application, we can use a YAML file like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample-app
  namespace: my-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: sample-app
  template:
    metadata:
      labels:
        app: sample-app
    spec:
      containers:
      - name: sample-app
        image: my-sample-app:latest
        ports:
        - containerPort: 8080

Apply the Configuration: We use kubectl to apply the configurations.
```
kubectl apply -f sample-app-deployment.yaml
```
Verify Deployment: We check to make sure our application is running well.
```
kubectl get pods -n my-app
```

This setup will get our Kubernetes environment ready for a custom Istio Ingress Gateway Controller. This allows us to manage ingress traffic well. For more advanced setups, we can check the Istio documentation.

Configuring Istio Ingress Gateway Custom Resources

To set up a custom Istio Ingress Gateway in Kubernetes, we need to create some important custom resources. We will define the Gateway and VirtualService resources. These resources help manage incoming traffic.

Creating a Gateway Resource

The Gateway resource tells how to route traffic to our services. Here is a simple YAML example for a Gateway resource:

apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
  name: my-gateway
  namespace: istio-system
spec:
  selector:
    istio: ingressgateway # use Istio's default ingress gateway
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*"
  - port:
      number: 443
      name: https
      protocol: HTTPS
    tls:
      mode: SIMPLE
      credentialName: my-credential # name of the secret for TLS
    hosts:
    - "*"

Creating a VirtualService Resource

The VirtualService resource sets the routing rules for our service. It uses the host and path to decide how to route traffic. Here is a simple example for a VirtualService:

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: my-virtualservice
  namespace: default
spec:
  hosts:
  - my-service.default.svc.cluster.local
  gateways:
  - istio-system/my-gateway
  http:
  - match:
    - uri:
        prefix: /api
    route:
    - destination:
        host: my-service
        port:
          number: 80
  - match:
    - uri:
        prefix: /blog
    route:
    - destination:
        host: my-blog-service
        port:
          number: 80

Applying the Configuration

To apply these settings, we save them to YAML files. For example, we can use gateway.yaml and virtualservice.yaml. Then we run these commands:

kubectl apply -f gateway.yaml
kubectl apply -f virtualservice.yaml

Testing the Configuration

After we apply the configurations, we can test our Istio Ingress Gateway setup. We send HTTP requests to the routes we defined. For example, we can use curl to test the API route:

curl http://<INGRESS-GATEWAY-IP>/api/your-endpoint

We need to replace <INGRESS-GATEWAY-IP> with the external IP of our Istio Ingress Gateway. We can find this by running:

kubectl get svc istio-ingressgateway -n istio-system

Now that we have configured the Gateway and VirtualService, our custom Istio Ingress Gateway is ready. It can route incoming traffic to our services. For more information on configuring Ingress, we can check out this resource on Kubernetes Ingress.

Deploying Your Custom Istio Ingress Gateway Controller

To deploy our custom Istio Ingress Gateway Controller in Kubernetes, we can follow these easy steps:

Create a Namespace for Istio:
```
kubectl create namespace istio-system
```

Deploy the Custom Ingress Gateway: First, we need to create a YAML file called custom-ingress-gateway.yaml with our settings. This example shows how to set up a Gateway with certain ports and protocols.

apiVersion: v1
kind: Service
metadata:
  name: custom-ingress-gateway
  namespace: istio-system
spec:
  type: LoadBalancer
  ports:
  - port: 80
    targetPort: 8080
    name: http
  - port: 443
    targetPort: 8443
    name: https
  selector:
    istio: custom-ingress-gateway
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: custom-ingress-gateway
  namespace: istio-system
spec:
  replicas: 1
  selector:
    matchLabels:
      istio: custom-ingress-gateway
  template:
    metadata:
      labels:
        istio: custom-ingress-gateway
    spec:
      containers:
      - name: custom-ingress-gateway
        image: your-custom-image:latest
        ports:
        - containerPort: 8080
        - containerPort: 8443

We can deploy it using:

kubectl apply -f custom-ingress-gateway.yaml

Configure Istio Gateway: Next, we need to create a Gateway resource. This will help in setting how the Ingress Gateway manages traffic. Save this as custom-gateway.yaml.

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: custom-gateway
  namespace: istio-system
spec:
  selector:
    istio: custom-ingress-gateway
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*"
  - port:
      number: 443
      name: https
      protocol: HTTPS
    hosts:
    - "*"
    tls:
      mode: SIMPLE
      privateKey: sds://path/to/private/key
      serverCertificate: sds://path/to/server/cert

Now, we apply the Gateway configuration:

kubectl apply -f custom-gateway.yaml

Verify Deployment: We should check the status of the Deployment and Service:

kubectl get deployments -n istio-system
kubectl get services -n istio-system

Access the Ingress Gateway: After deployment, we can access our applications using the external IP of the LoadBalancer. To find the IP, we use:
```
kubectl get svc custom-ingress-gateway -n istio-system
```

Set Up Virtual Services: To route traffic through our custom Ingress Gateway, we need to define a Virtual Service. Here is an example in virtual-service.yaml:

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: my-service
  namespace: default
spec:
  hosts:
  - my-service.example.com
  gateways:
  - istio-system/custom-gateway
  http:
  - match:
    - uri:
        prefix: /
    route:
    - destination:
        host: my-service
        port:
          number: 80

We apply the Virtual Service configuration:

kubectl apply -f virtual-service.yaml

Now, our custom Istio Ingress Gateway Controller should be deployed and ready to handle traffic as we want. For more information on deploying Kubernetes applications, we can check this guide.

Testing Your Custom Istio Ingress Gateway Controller

To test your custom Istio Ingress Gateway Controller in Kubernetes, we can follow these simple steps.

Deploy a Sample Application: First, we need to deploy a sample application. This application will be exposed through the Istio Ingress Gateway. For example, we can use a simple HTTP application like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample-app
  labels:
    app: sample-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: sample-app
  template:
    metadata:
      labels:
        app: sample-app
    spec:
      containers:
      - name: sample-app
        image: hashicorp/http-echo:latest
        args:
        - "-text=Hello from Sample App"
        ports:
        - containerPort: 5678
---
apiVersion: v1
kind: Service
metadata:
  name: sample-app
spec:
  ports:
  - port: 80
    targetPort: 5678
  selector:
    app: sample-app

We apply this configuration with: bash kubectl apply -f sample-app.yaml

Create an Istio Gateway: Next, we create an Istio Gateway to route traffic to our sample application.

apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
  name: sample-app-gateway
spec:
  selector:
    istio: ingressgateway # Use Istio's default ingress gateway
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*"

We apply this configuration with: bash kubectl apply -f sample-app-gateway.yaml

Create a Virtual Service: Then, we need to set up a Virtual Service. This will route traffic from the Gateway to the sample application.

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: sample-app-vs
spec:
  hosts:
  - "*"
  gateways:
  - sample-app-gateway
  http:
  - match:
    - uri:
        prefix: /
    route:
    - destination:
        host: sample-app
        port:
          number: 80

We apply this Virtual Service configuration with: bash kubectl apply -f sample-app-vs.yaml

Test the Ingress Gateway: Now, we need to get the external IP address of the Istio Ingress Gateway. Then, we can send an HTTP request to check if it works.
```
# Get the external IP
kubectl get svc istio-ingressgateway -n istio-system

# Use curl to test the endpoint (replace <EXTERNAL-IP> with the actual IP)
curl http://<EXTERNAL-IP>
```
We should see a response that says: “Hello from Sample App”.
Check Logs: Finally, we can monitor the logs of the Istio Ingress Gateway. This helps us to fix any problems.
```
kubectl logs -l istio=ingressgateway -n istio-system
```

This process helps us make sure that our custom Istio Ingress Gateway Controller is working well and routing traffic correctly. For more details on configuring Ingress in Kubernetes, we can look at this Kubernetes Ingress article.

Frequently Asked Questions

What is an Istio Ingress Gateway Controller?

We can say that an Istio Ingress Gateway Controller works like a bridge. It connects outside traffic to the services in a Kubernetes cluster that uses Istio. It helps us manage incoming traffic. We can use it for advanced traffic routing, security features, and monitoring. This makes it very important for running microservices in Kubernetes. To make a custom Istio Ingress Gateway Controller, we should understand how to configure it.

How do I set up Istio for my Kubernetes cluster?

To set up Istio in our Kubernetes cluster, we first need to install Istio. We can do this using the Istio Operator or Helm. After we install it, we need to enable the Istio Ingress Gateway. We can apply the right configurations for this. For detailed steps, we should check how to install and configure Istio. This will help us manage traffic well.

What are the prerequisites for creating a custom Istio Ingress Gateway Controller?

Before we create a custom Istio Ingress Gateway Controller, we need to make sure our Kubernetes cluster is set up right and has Istio installed. It is also important to know about Kubernetes Custom Resource Definitions (CRDs). We will need these to define our own ingress resources. Also, we should have our development environment ready for applying the configurations and testing the controller.

How can I test my custom Istio Ingress Gateway Controller?

To test our custom Istio Ingress Gateway Controller, we should deploy a test application in our Kubernetes cluster. We can expose it through the gateway. We can use tools like curl or Postman to send requests to the application via the Ingress Gateway. It is very important to check that the routing rules and security policies work as we expect.

Where can I find more resources on Kubernetes and Istio?

For more resources on Kubernetes and Istio, we can look for different topics about Kubernetes basics, deployment strategies, and service management. For instance, this article gives us insights on how to configure Ingress for outside access. This will help us understand more about Istio Ingress Gateway Controllers.