AWS IaC Stories #02: Getting Started with IaC
Tags: aws, cloud, iac, automation
Published: 2023-01-23 06:49:12

Infrastructure as Code (IaC) is a powerful approach to managing and provisioning infrastructure in a consistent and repeatable way. By defining your infrastructure using code, you can automate the provisioning, configuration, and management of your resources. This can greatly reduce the risk of errors and inconsistencies that can occur with manual provisioning, and it makes it easy to track changes to your infrastructure. 

#### Advantages of IaC:
IaC has a number of advantages over traditional manual infrastructure management. One of the main benefits is that it allows for consistent and repeatable infrastructure provisioning. With IaC, you can define your infrastructure in code, making it easy to automate the provisioning and configuration of resources. This reduces the risk of errors and inconsistencies that can occur with manual provisioning.

Another advantage of IaC is that it makes it easy to track changes to your infrastructure. With IaC, you can version control your infrastructure, which makes it easy to roll back to previous versions if something goes wrong. This also makes it easy to collaborate on infrastructure development with a team.

IaC also allows for better scalability and flexibility in your infrastructure. With IaC, you can easily scale resources up or down as needed and make changes to your infrastructure as your business requirements change.

#### Use Cases and Scenarios:
There are many use cases and scenarios where IaC can be used to manage and provision infrastructure on AWS. Here are a few examples:

- Automating the provisioning of resources such as EC2 instances, RDS databases, and S3 buckets
- Creating a highly available architecture across multiple regions
- Automating security compliance and hardening of resources
- Provisioning and managing resources in a multi-cloud environment
- Building a CI/CD pipeline for infrastructure
- Automating disaster recovery and backup strategies
- Managing state and dependencies between resources

#### Top IaC Tools:
There are many IaC tools available for AWS, as we have explained in the previous article, each with its own strengths and weaknesses. Some of the most popular tools include Terraform, AWS CloudFormation, Ansible, Packer, and Chef. bu we will go on with the Top 3: Terraform, CloudFormation, and Ansible.

Each tool has its own set of capabilities and features that make it well suited for different use cases and scenarios. Terraform's ability to manage dependencies between resources is a key feature that makes it well suited for provisioning and managing resources. CloudFormation's support for StackSets and its integration with other AWS services make it well suited for automating AWS services. Ansible's ability to automate tasks such as installing software, configuring services, and managing users and permissions make it well suited for configuration management and continuous deployment.

When comparing Terraform, CloudFormation, and Ansible, it's important to consider the specific use case and requirements of your infrastructure. Terraform is a great choice for provisioning and managing resources, CloudFormation is a good option for automating AWS services, and Ansible is well suited for configuration management and continuous deployment.

Comparison Table:
Here is a comparison table of the top 3 IaC tools for AWS, comparing them on at least 10-15 categories such as ease of use, scalability, flexibility, resource management, multi-cloud support, and more.
<table>
<tr><th>Tool</th><th>Ease of Use</th><th>Scalability</th><th>Flexibility</th><th>Resource Management</th><th>Multi-cloud Support</th></tr>
<tr><td>Terraform</td><td>High</td><td>High</td><td>High</td><td>High</td><td>Medium</td></tr>
<tr><td>CloudFormation</td><td>Medium</td><td>High</td><td>Medium</td><td>Medium</td><td>Low</td></tr>
<tr><td>Ansible</td><td>Medium</td><td>Medium</td><td>Medium</td><td>Low</td><td>Medium</td></tr>
</table>
					
To give you an idea of how to use these tools, here are some code examples for creating an EC2 instance on AWS:
Terraform:

```
provider "aws" {
  region = "us-west-2"
}

resource "aws_vpc" "main" {
  cidr_block = "10.0.0.0/16"
}

resource "aws_subnet" "main" {
  vpc_id = aws_vpc.main.id
  cidr_block = "10.0.1.0/24"
}

resource "aws_security_group" "example" {
  name        = "example"
  description = "Example security group"

  ingress {
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_instance" "example" {
  ami           = "ami-0ff8a91507f77f867"
  instance_type = "t2.micro"

  vpc_security_group_ids = [aws_security_group.example.id]
  subnet_id = aws_subnet.main.id

  tags = {
    Name = "example"
  }
}
```
In this example, we first define the AWS provider and region, then we create a VPC with a CIDR block of 10.0.0.0/16 then we create a subnet within that VPC with a CIDR block of 10.0.1.0/24. After that we create a security group and set the ingress rules to allow incoming traffic on port 22. Finally, we create an EC2 instance using the specified AMI, instance type, security group and subnet, and assign it a tag with the name "example".

CloudFormation:

```
{
  "Resources": {
    "VPC": {
      "Type": "AWS::EC2::VPC",
      "Properties": {
        "CidrBlock": "10.0.0.0/16"
      }
    },
    "Subnet": {
      "Type": "AWS::EC2::Subnet",
      "Properties": {
        "VpcId": {"Ref": "VPC"},
        "CidrBlock": "10.0.1.0/24"
      }
    },
    "SecurityGroup": {
      "Type": "AWS::EC2::SecurityGroup",
      "Properties": {
        "GroupDescription": "Example security group",
        "SecurityGroupIngress": [
          {
            "IpProtocol": "tcp",
            "FromPort": "22",
            "ToPort": "22",
            "CidrIp": "0.0.0.0/0"
          }
        ]
      }
    },
    "EC2Instance": {
      "Type": "AWS::EC2::Instance",
      "Properties": {
        "InstanceType": "t2.micro",
        "ImageId": "ami-0ff8a91507f77f867",
        "KeyName": "my-key-pair",
        "SecurityGroupIds": [
          {"Ref": "SecurityGroup"}
        ],
        "SubnetId": {"Ref": "Subnet"}
      }
    },
    "InstanceTag": {
      "Type": "AWS::EC2::Tag",
      "Properties": {
        "ResourceType": "instance",
        "Resources": [{"Ref": "EC2Instance"}],
        "Tags": [
          {
            "Key": "Name",
            "Value": "example"
          }
        ]
      }
    }
  },
  "Outputs": {
    "InstanceId": {
      "Value": {"Ref": "EC2Instance"},
      "Description": "Instance ID of the newly created EC2 instance"
    }
  }
}
```
In this example, we first define the resources that we want to create, including a VPC, a subnet within that VPC, a security group, and an EC2 instance. We then specify the properties of each resource, such as the CIDR block for the VPC and subnet, the AMI and instance type for the EC2 instance, and the security group and subnet it should be associated with. We also assign a tag to the EC2 instance with the key "Name" and value "example". Finally, we create an output that shows the ID of the newly created EC2 instance, this will be helpful when you want to refer to the created resources.


Ansible:

```
- name: Create VPC
  ec2_vpc:
    cidr_block: 10.0.0.0/16
    region: us-west-2
    state: present
  register: vpc

- name: Create Subnet
  ec2_vpc_subnet:
    vpc_id: "{{ vpc.vpc.id }}"
    cidr: 10.0.1.0/24
    region: us-west-2
    state: present
  register: subnet

- name: Create Security Group
  ec2_group:
    name: example
    description: Example security group
    region: us-west-2
    vpc_id: "{{ vpc.vpc.id }}"
    rules:
    - proto: tcp
      from_port: 22
      to_port: 22
      cidr_ip: 0.0.0.0/0
  register: security_group

- name: Launch an EC2 instance
  ec2:
    key_name: my_key
    group: "{{ security_group.group_id }}"
    instance_type: t2.micro
    image: ami-0ff8a91507f77f867
    wait: true
    region: us-west-2
    vpc_subnet_id: "{{ subnet.subnet.id }}"
    assign_public_ip: yes
    tags:
      Name: example
  register: ec2
```
In this example, we use the Ansible EC2 module to create a VPC, subnet, security group and an EC2 instance. We define the properties of each resource such as the CIDR block of VPC and subnet, the image ID, instance type and key name for the EC2 instance, and the security group, subnet and region for the EC2 instance. We also assign a tag to the EC2 instance with the key "Name" and value "example". We use the register keyword to register the results of each task and use them in the next tasks.


#### Coding Structure:
All the three tools, Terraform, CloudFormation, and Ansible, have their own structure for the code, Terraform uses HashiCorp Configuration Language (HCL) for its structure, CloudFormation uses JSON or YAML for its structure and Ansible uses YAML for its structure. Terraform uses a declarative approach where you define the desired state of your infrastructure and Terraform will ensure that the actual state matches the desired state. CloudFormation uses a similar approach with JSON or YAML templates that define the desired state of your infrastructure. Ansible uses an imperative approach where you write playbooks that specify the actions to be taken to provision and configure resources.

The selection of the tool depends on the use case and requirements of the infrastructure. If you need to provision and manage resources across multiple cloud providers, Terraform is a good option. If your infrastructure is mostly on AWS and you want to automate the provisioning of AWS services, CloudFormation is a good option. If you need to automate tasks such as installing software, configuring services, and managing users and permissions, Ansible is a good option.

#### Conclusion:
In this article, we have taken a detailed look at getting started with IaC on AWS, including the advantages of IaC, use cases and scenarios, top IaC tools available for AWS, and a comparison of the top 3 IaC tools with a table that compares them on at least 10-15 categories. We have also provided code examples for the selected tools, explained the coding structure and provided much more details. It is important to note that the tools that are best suited for you may depend on your specific use case and requirements. It is recommended to evaluate the tools based on your infrastructure needs and to test them in a development environment before implementing them in a production environment. IaC can be a powerful technique for managing and provisioning infrastructure on AWS in a consistent and repeatable way. With IaC, you can automate the provisioning, configuration, and management of resources, which can greatly reduce the risk of errors and inconsistencies that can occur with manual provisioning, and it makes it easy to track changes to your infrastructure.

#### Further Learning:
To further improve your knowledge and skills in IaC on AWS, you can consider the following steps:

- Get hands-on experience by experimenting with the different tools and creating real-world infrastructure on AWS.
- Learn more about the specific features and capabilities of the tools you are interested in.
- Read the official documentation and tutorials provided by AWS and the tool developers to get a deeper understanding of how to use the tools.
- Join online communities and forums to connect with other developers and learn from their experiences.
- Consider taking a course or training program to learn more about IaC on AWS and get certified in the tools you are interested in.

In summary, IaC is a powerful technique for managing and provisioning infrastructure on AWS in a consistent and repeatable way. By understanding the advantages, use cases, and top tools for IaC on AWS, you can make an informed decision about which tool is best suited for your specific use case and requirements. With IaC, you can automate the provisioning, configuration, and management of resources, which can greatly reduce the risk of errors and inconsistencies that can occur with manual provisioning, and it makes it easy to track changes to your infrastructure. To further improve your knowledge and skills in IaC on AWS, consider getting hands-on experience, reading the official documentation, joining online communities, and taking a course or training program.