CloudFormation is a powerful AWS service that allows developers to automate the creation and deployment of cloud infrastructure. In this article, we will take a closer look at what CloudFormation is and how it can be used to simplify the process of provisioning and managing cloud resources.
CloudFormation is a service that allows developers to define and provision cloud infrastructure using templates written in JSON or YAML. Once a template has been defined, CloudFormation can be used to create, update, and delete a stack of resources based on that template.
One of the benefits of using CloudFormation is that it allows for infrastructure to be defined as code. This means that infrastructure can be versioned, tracked, and automated just like any other code resource.
Another benefit of CloudFormation is that it can be used to provision resources across multiple AWS accounts and regions. This can be helpful when managing resources for development, testing, and production environments.
A CloudFormation template is a JSON or YAML document that defines a stack of AWS resources. A template can include multiple resources, each of which can be defined using either a simple or nested format.
A simple format resource is defined by a single JSON or YAML object. This object must include a Type property that specifies the type of resource to be created, and a Properties property that defines the resource's properties.
A nested format resource is defined by a JSON or YAML object that includes a Type property and a Properties property, as well as a NestedStackId property. The NestedStackId property contains the stack ID of a nested stack, which is a stack that is created within another stack.
Once a CloudFormation template has been defined, it can be used to create a new stack. To create a stack, you must specify a stack name, a template URL, and a set of parameters.
The stack name is used to uniquely identify the stack. The template URL is the location of the template file. The template file can be stored in an Amazon S3 bucket, or it can be inline.
The parameters are a set of key-value pairs that are used to configure the stack. The keys must be specified in the template, and the values must be provided when the stack is created.
Once the stack has been created, CloudFormation will provision the resources that are defined in the template. This process can take a few minutes to complete.
Once a stack has been created, it can be updated. To update a stack, you must specify a new template URL and a set of parameters.
When you update a stack, CloudFormation will first compare the new template to the existing template. If there are no changes, CloudFormation will do nothing. If there are changes, CloudFormation will update the stack.
Once a stack is no longer needed, it can be deleted. Deleting a stack will delete all of the resources that are defined in the stack.
CloudFormation can be used to provision nearly any type of AWS resource. Some common use cases for CloudFormation include:
Here are a few examples of CloudFormation templates that can be used to provision common AWS resources.
This template can be used to create a VPC with a public and private subnet.
AWSTemplateFormatVersion: 2010-09-09
Description: A VPC with a public and private subnet.
Parameters:
VpcCidr:
Description: The CIDR block for the VPC.
Type: String
Default: 172.16.0.0/16
PublicSubnet1Cidr:
Description: The CIDR block for the public subnet.
Type: String
Default: 172.16.0.0/24
PrivateSubnet1Cidr:
Description: The CIDR block for the private subnet.
Type: String
Default: 172.16.1.0/24
Resources:
Vpc:
Type: AWS::EC2::VPC
Properties:
CidrBlock: !Ref VpcCidr
InstanceTenancy: default
PublicSubnet1:
Type: AWS::EC2::Subnet
Properties:
VpcId: !Ref Vpc
CidrBlock: !Ref PublicSubnet1Cidr
AvailabilityZone: us-east-1a
PrivateSubnet1:
Type: AWS::EC2::Subnet
Properties:
VpcId: !Ref Vpc
CidrBlock: !Ref PrivateSubnet1Cidr
AvailabilityZone: us-east-1a
This template can be used to launch an EC2 instance.
AWSTemplateFormatVersion: 2010-09-09
Description: A simple EC2 instance.
Parameters:
KeyName:
Description: The name of the SSH key pair to use.
Type: String
InstanceType:
Description: The type of EC2 instance to launch.
Type: String
Default: t2.micro
ImageId:
Description: The ID of the AMI to use.
Type: String
Resources:
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
KeyName: !Ref KeyName
InstanceType: !Ref InstanceType
ImageId: !Ref ImageId
This template can be used to create an RDS database.
AWSTemplateFormatVersion: 2010-09-09
Description: A simple RDS database.
Parameters:
DbInstanceIdentifier:
Description: The database instance identifier.
Type: String
DbInstanceClass:
Description: The database instance class.
Type: String
Default: db.t2.micro
DbName:
Description: The database name.
Type: String
Resources:
DbInstance:
Type: AWS::RDS::DBInstance
Properties:
DbInstanceIdentifier: !Ref DbInstanceIdentifier
DbInstanceClass: !Ref DbInstanceClass
Engine: MySQL
MasterUsername: root
MasterUserPassword: password
AllocatedStorage: 5
DbName: !Ref DbName
This template can be used to create an S3 bucket.
AWSTemplateFormatVersion: 2010-09-09
Description: A simple S3 bucket.
Parameters:
BucketName:
Description: The name of the S3 bucket.
Type: String
Resources:
Bucket:
Type: AWS::S3::Bucket
Properties:
BucketName: !Ref BucketName
CloudFormation is a powerful AWS service that allows developers to automate the creation and deployment of cloud infrastructure. In this article, we took a closer look at what CloudFormation is and how it can be used to simplify the process of provisioning and managing cloud resources.