Introduction

This document covers  Integrated Edge Cloud(IEC) Type 2.

The purpose of this terraform template is to provision a multi-node Kubernetes cluster on AWS using microk8s. MicroK8s offers a lightweight Kubernetes environment for edge use cases.

How to use this document

The following sections describe the prerequisites for planning an IEC deployment. Once these are met, installation steps provided should be followed in order to obtain an IEC compliant Kubernetes cluster.

Pre-Installation Requirements

1. Install terraform - https://www.terraform.io/downloads.html

(a)Download the zip file based on the server type.
(b)Unzip the file to get the terraform binary.
(c)Currently supported Ubuntu version is 18.04

2. IAM Access Keys - Permissions required for running the template - AmazonEC2FullAccess

3. PEM file for the AWS Key used in the terraform template

NOTE: Replace fields in the variable.tf file with your corresponding values

In order for Terraform to be able to create resources in your AWS account, you will need to configure the AWS credentials. One of the easiest of which is to set the following environment variables:

export AWS_ACCESS_KEY_ID=(your access key id)
export AWS_SECRET_ACCESS_KEY=(your secret access key)

The credentials can also be set in the variable.tf file.

_{variable "access_key" {
description = "access_key"
default = <insertKey>
}}

_{variable "secret_key" {
description = "secret_key"
default = <insertKey>
}}

Terraform Template

The template contains main.tf file, variable.tf file, pem file (add your pem file here) and worker_user_data.tmpl
You can move the pem file to the directory where this template resides or you can change the location of the pem file in the main.tf file.

Master's main.tf file

The first step to using Terraform is typically to configure the provider(s) you want to use.
This tells Terraform that you are going to be using the AWS provider and that you wish to deploy your infrastructure in the us-east-2 region.

provider "aws" {
region = var.aws_region
}

The user_data installs the microk8s inside the EC2 instance.

#!/bin/bash
sudo su
apt update -y >> microk8s_install.log
apt install snapd -y >> microk8s_install.log
snap install core >> microk8s_install.log
export PATH=$PATH:/snap/bin
snap install microk8s --classic >> microk8s_install.log
microk8s status --wait-ready
microk8s enable dns >> microk8s_install.log
microk8s add-node > microk8s.join_token
microk8s config > configFile

Since terraform does not wait until the user_data is executed, we exec into the instance by using the 'remote-exec' type provisioner and add the following script. This script will make terraform wait for util microk8s.join-token file is created.

provisioner "remote-exec" {
inline = ["until [ -f /microk8s.join_token ]; do sleep 5; done; cat /microk8s.join_token"]
}

For testing purposes, we create an 'ALLOW ALL' ingress and egress rule security group.

Variables.tf file

The provider and the resource blocks in the main.tf file can be configured by changing the values in variables.tf file.
For example, if you want to change the aws_instace type from t2.small to t2.micro, replace the value here in this block.

variable "aws_instance" {
type = string
description = "instance_type"
default = "t2.small"
}

Other resource-specific values like aws_region, aws_ami, vpc and the subnet can also be changed the same way by editing the variable.tf file.

Apply terraform

To create a master node with microk8s, run the following commands.
terraform init
terraform plan
terraform apply

Once the worked nodes are created, they will be connected to the master. A multi-node k8s cluster will be provisioned with calico CNI.