Bootstrapping Kubernetes Cluster with CloudFormation
Tags: kubernetes, aws, cloud, tutorial
Published: 2023-02-14 17:06:27

## Introduction

Kubernetes is an open-source platform for managing containerized applications. It is one of the most widely used tools for managing large-scale deployments of applications and provides an impressive array of features, such as service discovery, auto-scaling, and container orchestration.
Kubernetes also enables users to configure and manage their applications, scaling them quickly and easily. This includes creating deployments, services, and ingresses, as well as configuring the networking between services. Additionally, users can add monitoring and logging to keep track of their applications and ensure they are running optimally. Finally, users can use CloudFormation to automate the deployment of their applications on the Kubernetes cluster.
CloudFormation is an Amazon Web Services (AWS) service that enables users to create and manage configuration files for their cloud resources. With CloudFormation, users can easily set up, configure, and manage Kubernetes clusters with minimal effort and without having to manually configure every aspect. In this blog post, we'll explore how to bootstrap a Kubernetes cluster with CloudFormation, and how to configure and manage it once it is up and running.

## Overview

CloudFormation makes it easy to bootstrap a Kubernetes cluster with minimal effort. It enables users to create a template that defines the desired configuration of the cluster, such as the number of nodes, the instance types, and the networking settings. Once the template is created, users can deploy the cluster by running the CloudFormation stack. Once the stack is complete, users can begin configuring and managing the cluster, installing the necessary software components, configuring the networking between the nodes, and scaling their applications quickly and easily. Additionally, users can use CloudFormation to automate the deployment of their applications on the Kubernetes cluster. In this blog post, we'll explore how to bootstrap a Kubernetes cluster with CloudFormation, and how to configure and manage it once it is up and running.

## Creating a Kubernetes Cluster

The first step in bootstrapping a Kubernetes cluster with CloudFormation is to create a template that defines the desired configuration of the cluster. The template should include the desired number of nodes, their instance types, and their associated roles. Additionally, the template should include all the necessary software components and configurations, such as the Kubernetes Dashboard and kubectl, as well as the desired networking settings. Once the template is created, users can deploy the cluster by running the CloudFormation stack. Once the stack is complete, the cluster is ready to be used.

The following is a sample template for creating a Kubernetes Cluster with CloudFormation.

```
---
AWSTemplateFormatVersion: '2010-09-09'
Parameters:
  VpcId:
    Type: AWS::EC2::VPC::Id
    Description: ID of the VPC in which to create the Kubernetes cluster
  SubnetIds:
    Type: List<AWS::EC2::Subnet::Id>
    Description: List of Subnet IDs in which to create the Kubernetes cluster
  KeyPairName:
    Type: AWS::EC2::KeyPair::KeyName
    Description: Name of the EC2 Key Pair to use for SSH access to worker nodes
  ClusterName:
    Type: String
    Description: Name of the Kubernetes cluster to create
Resources:
  ControlPlaneSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      VpcId: !Ref VpcId
      GroupDescription: Allow inbound traffic to the Kubernetes control plane
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 22
          ToPort: 22
          CidrIp: 0.0.0.0/0
  WorkerNodeSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      VpcId: !Ref VpcId
      GroupDescription: Allow inbound traffic to Kubernetes worker nodes
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 22
          ToPort: 22
          CidrIp: 0.0.0.0/0
  ControlPlaneInstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Roles:
        - !Ref ControlPlaneRole
  ControlPlaneRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - ec2.amazonaws.com
            Action:
              - sts:AssumeRole
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/AmazonEKSClusterPolicy
        - arn:aws:iam::aws:policy/AmazonEKSServicePolicy
  ControlPlaneInstance:
    Type: AWS::EC2::Instance
    Properties:
      ImageId: ami-0b69ea66ff7391e80
      InstanceType: t2.micro
      KeyName: !Ref KeyPairName
      NetworkInterfaces:
        - DeviceIndex: 0
          AssociatePublicIpAddress: true
          GroupSet:
            - !Ref ControlPlaneSecurityGroup
          SubnetId: !Select [0, !Ref SubnetIds]
      IamInstanceProfile: !Ref ControlPlaneInstanceProfile
      UserData:
        Fn::Base64: !Sub |
          #!/bin/bash
          echo 'net.bridge.bridge-nf-call-iptables=1' | tee -a /etc/sysctl.conf
          sysctl -p
          yum update -y
          amazon-linux-extras install docker -y
          service docker start
          usermod -a -G docker ec2-user
          curl -o /usr/local/bin/kubectl https://amazon-eks.s3.us-west-2.amazonaws.com/1.21.2/2021-07-05/bin/linux/amd64/kubectl
          chmod +x /usr/local/bin/kubectl
          echo 'export PATH=$PATH:/usr/local/bin' >> /etc/bashrc
          curl --silent --location "https://github.com/weaveworks/eksctl/releases

```

## Configuring the Kubernetes Cluster

Once the Kubernetes cluster has been created, users can begin configuring it. This includes installing the necessary software components, such as the Kubernetes Dashboard and kubectl, as well as configuring the networking between the nodes. Additionally, users can configure the cluster to run specific workloads, such as batch jobs or web applications, and to use specific types of storage, such as persistent storage or local storage.

Once the cluster is configured, users can begin deploying applications and services to the cluster in a number of ways. This can be accomplished by using the Kubernetes APIs, utilizing tools such as Helm and Operators, or even with the Kubernetes dashboard to monitor the health of the cluster and identify any potential issues. On top of that, users can also use the AWS CLI to manage the nodes, services, and applications running on the cluster, as well as to create and manage backups of the cluster's data. This is especially important for larger clusters, as they often require more rigorous maintenance and monitoring to ensure that the cluster is running optimally. Additionally, users can also use the AWS CLI to scale the cluster up or down, depending on the current demand for resources. This provides users with the flexibility to quickly and easily adjust their application and service deployment strategy, allowing them to quickly and efficiently respond to changes in customer demand.

Once the cluster is up and running, users can use a variety of tools to manage it. The AWS Command Line Interface (CLI) provides an easy to use interface for managing the cluster's nodes, services, and applications. Additionally, users can use the Kubernetes APIs to deploy and manage applications running on the cluster. Additionally, users can take advantage of the Kubernetes ecosystem of tools, such as Helm and Operators, to further extend the capabilities of their cluster. Finally, users can use the Kubernetes dashboard to monitor the health of the cluster and identify any potential issues.