Kubernetes Cluster on AWS

23/07/2019

Create a single node Kubernetes cluster, fully integrated with AWS (automatic Load Balancers for frontend services) for testing purposes…

Prerequisites

  • An AWS account.
  • An SSH Keypair created in AWS and have the PEM file stored locally.
  • Your AWS Access Key & Secret Key

Following this tutorial will incur AWS costs.

Install Kubectl

kubectl (kubernetes control) is the command line utility you will use to interact with your Kubernetes cluster once it’s up & running.

Depending on your operating system, installation will obviously be different but the official instructions here are a great place to start.

Before you proceed, ensure you can successfully run the command kubectl version in your command line.

Note: You might see this warning. It’s safe to ignore.

The connection to the server localhost:8080 was refused - did you specify the right host or port?

Generate Public Key From PEM

Ensure your pem has 0600 permissions: chmod 0600 key.pem

Generate the public key from your private key PEM file:

ssh-keygen -y -f key.pem > key.pub

Install EKSCTL Utility

eksctl (Amazon Elastic Kubernetes Service Control) is a command line utility which makes it easy to interact with the AWS EKS service.

Installing eksctl is very easy, depending on your OS:

Standard Linux Install

curl --silent --location "https://github.com/weaveworks/eksctl/releases/download/latest_release/eksctl_$(uname -s)_amd64.tar.gz" | tar xz -C /tmp
sudo mv /tmp/eksctl /usr/local/bin

MacOS Install Using Homebrew

brew tap weaveworks/tap
brew install weaveworks/tap/eksctl

Windows Install Using Chocolatey

chocolatey install eksctl

Before proceeding, ensure you can successfully run eksctl version in a command line.

Authenticating EKSCTL

Since eksctl will be interacting with AWS on our behalf, we need to ensure it has permissions to authenticate.

Ensure you have the following folder structure & file created. If you’ve previously used any other tool that interacts with AWS (kops, Terraform etc) then chances are you’ll be good to go & won’t need to recreate anything.

Make sure the ~/.aws folder exists and create a file called credentials inside. Edit the credentials file to include your AWS Access Key and AWS Secret Key.

Your credentials file should look like this:

[default]
aws_access_key_id=AKIA***********
aws_secret_access_key=oRsRbKc*********

Cluster Definition File

Create a cluster definition file. eksctl will use this file to define exactly how we want our cluster to be created. The file can be called anything (as long as it’s saved with the .yaml extension).

I’ll call mine clusterDef.yaml and store it in my home directory ~/clusterDef.yaml

Note on YAML: YAML does not work with tabs. Use space characters only.
Use YAMLLint to validate your YAML file format.

apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig

metadata:
  name: single-node-cluster
  region: us-east-2

nodeGroups:
  - name: node-group-1
    instanceType: t2.medium
    desiredCapacity: 1
    ssh:
      publicKeyPath: /path/to/key.pub

Hopefully this should be fairly self explanatory. We create a cluster called single-node-cluster in the us-east-2 region which consists of a single node (desiredCapacity: 1) which is a t2.medium sized node. We also copy our public key onto the instance so that we can SSH into the node if needed (although that shouldn’t be required).

Create Cluster

All that’s left now is to actually create the cluster. eksctl makes this easy:

eksctl create cluster -f ~/clusterDef.yaml


$ eksctl create cluster -f /path/to/clusterDef.yaml
[i]  using region us-east-1
[i]  setting availability zones to [us-east-1b us-east-1c]
[i]  subnets for us-east-1b - public:192.168.0.0/19 private:192.168.64.0/19
[i]  subnets for us-east-1c - public:192.168.32.0/19 private:192.168.96.0/19
[i]  nodegroup "node-group-1" will use "ami-0f2e8e5663e16b436" [AmazonLinux2/1.13]
[i]  using SSH public key "/path/to/file.pub" as "eksctl-single-node-cluster-nodegroup-node-group-1-6f:84:05:83:7e:99:89:67:69:a6:7d:72:d7:0a:a4:c7" 
[i]  using Kubernetes version 1.13
[i]  creating EKS cluster "single-node-cluster" in "us-east-1" region
[i]  1 nodegroup (node-group-1) was included
[i]  will create a CloudFormation stack for cluster itself and 1 nodegroup stack(s)
[i]  if you encounter any issues, check CloudFormation console or try 'eksctl utils describe-stacks --region=us-east-1 --name=single-node-cluster'
[i]  2 sequential tasks: { create cluster control plane "single-node-cluster", create nodegroup "node-group-1" }
[i]  building cluster stack "eksctl-single-node-cluster-cluster"
[i]  deploying stack "eksctl-single-node-cluster-cluster"
[i]  building nodegroup stack "eksctl-single-node-cluster-nodegroup-node-group-1"
[i]  --nodes-min=1 was set automatically for nodegroup node-group-1
[i]  --nodes-max=1 was set automatically for nodegroup node-group-1
[i]  deploying stack "eksctl-single-node-cluster-nodegroup-node-group-1"
[✔]  all EKS cluster resource for "single-node-cluster" had been created
[✔]  saved kubeconfig as "/.../.kube/config"
[i]  adding role "arn:aws:iam::782430655514:role/eksctl-single-node-cluster-nodegr-NodeInstanceRole-DJGENWOS1P4E" to auth ConfigMap
[i]  nodegroup "node-group-1" has 0 node(s)
[i]  waiting for at least 1 node(s) to become ready in "node-group-1"
[i]  nodegroup "node-group-1" has 1 node(s)
[i]  node "ip-192-168-10-142.ec2.internal" is ready
[i]  kubectl command should work with "/.../.kube/config", try 'kubectl get nodes'
[✔]  EKS cluster "single-node-cluster" in "us-east-1" region is ready

Delete Cluster

When you’re finished, delete the cluster with this command:

eksctl delete cluster -f ~/clusterDef.yaml

Deleting the cluster will not delete any resources that weren’t defined in the clusterDef file. In addition, deleting the cluster in this manner is still a bit buggy. Always double check that everything has actually been deleted to ensure you aren’t getting charged for leftover resources.

$ eksctl delete cluster -f ~/Documents/k8s/clusterDef.yaml 
[i]  using region us-east-1
[i]  deleting EKS cluster "single-node-cluster"
[✔]  kubeconfig has been updated
[i]  cleaning up LoadBalancer services
[i]  2 sequential tasks: { delete nodegroup "node-group-1", delete cluster control plane "single-node-cluster" [async] }
[i]  will delete stack "eksctl-single-node-cluster-nodegroup-node-group-1"
[i]  waiting for stack "eksctl-single-node-cluster-nodegroup-node-group-1" to get deleted
[i]  will delete stack "eksctl-single-node-cluster-cluster"
[✔]  all cluster resources were deleted

Summary

This post gives you a quick and easy way to spin up an on-demand Kubernetes cluster in AWS for test / demo purposes.

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