Deploy the Coredns Helm Chart on AWS EKS

Introduction

In this guide, we will deploy the CoreDNS Helm chart on an AWS EKS cluster using Pulumi. CoreDNS is a flexible, extensible DNS server that can serve as the Kubernetes cluster DNS. We will use Pulumi to automate the deployment process, ensuring that our infrastructure is defined as code.

Step-by-Step Explanation

Step 1: Set Up Pulumi and AWS

1. Ensure you have the Pulumi CLI installed. You can download it from Pulumi’s installation page.
2. Configure Pulumi to use your AWS credentials. You can do this by setting the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables.
3. Create a new Pulumi project using TypeScript: pulumi new aws-typescript.

Step 2: Create an EKS Cluster

1. Define a new EKS cluster in your Pulumi program. This will involve creating a VPC, subnets, and the EKS cluster itself.
2. Ensure that the EKS cluster is configured to use the appropriate IAM roles and security groups.

Step 3: Deploy the CoreDNS Helm Chart

1. Add the Pulumi Kubernetes provider to your project: npm install @pulumi/kubernetes.
2. Use the HelmRelease resource from the Pulumi Kubernetes provider to deploy the CoreDNS Helm chart.
3. Configure the Helm chart values as needed for your environment.

Step 4: Verify the Deployment

1. Once the deployment is complete, use kubectl to verify that the CoreDNS pods are running in your EKS cluster.
2. Ensure that the CoreDNS service is correctly configured and serving DNS requests within your cluster.

Conclusion

By following these steps, you have successfully deployed the CoreDNS Helm chart on an AWS EKS cluster using Pulumi. This approach ensures that your infrastructure is managed as code, providing a repeatable and auditable deployment process.

Full Code Example

import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";
import * as eks from "@pulumi/eks";
import * as k8s from "@pulumi/kubernetes";

// Create a VPC for our EKS cluster
const vpc = new aws.ec2.Vpc("eks-vpc", {
    cidrBlock: "10.0.0.0/16",
    enableDnsHostnames: true,
    enableDnsSupport: true,
    tags: { Name: "eks-vpc" },
});

// Create subnets for our VPC
const subnet = new aws.ec2.Subnet("eks-subnet", {
    vpcId: vpc.id,
    cidrBlock: "10.0.1.0/24",
    availabilityZone: "us-west-2a",
    tags: { Name: "eks-subnet" },
});

// Create a security group for our EKS cluster
const securityGroup = new aws.ec2.SecurityGroup("eks-security-group", {
    vpcId: vpc.id,
    description: "Allow all HTTP(s) traffic",
    ingress: [
        { protocol: "tcp", fromPort: 80, toPort: 80, cidrBlocks: ["0.0.0.0/0"] },
        { protocol: "tcp", fromPort: 443, toPort: 443, cidrBlocks: ["0.0.0.0/0"] },
    ],
    egress: [
        { protocol: "-1", fromPort: 0, toPort: 0, cidrBlocks: ["0.0.0.0/0"] },
    ],
    tags: { Name: "eks-security-group" },
});

// Create an EKS cluster
const eksCluster = new eks.Cluster("eks-cluster", {
    vpcId: vpc.id,
    subnetIds: [subnet.id],
    instanceType: "t2.medium",
    desiredCapacity: 2,
    minSize: 1,
    maxSize: 3,
    storageClasses: "gp2",
    deployDashboard: false,
    skipDefaultNodeGroup: true,
    tags: { Name: "eks-cluster" },
});

// Export the EKS cluster name
export const eksClusterName = eksCluster.eksCluster.name;

// Create a Kubernetes provider instance
const k8sProvider = new k8s.Provider("k8s-provider", {
    kubeconfig: eksCluster.kubeconfig,
});

// Deploy the CoreDNS Helm chart
const corednsRelease = new k8s.helm.v3.Release("coredns", {
    chart: "coredns",
    repositoryOpts: {
        repo: "https://charts.helm.sh/stable",
    },
    values: {}, // Add any custom values here
}, { provider: k8sProvider });

// Export the CoreDNS release name
export const corednsReleaseName = corednsRelease.name;