Infrastructure as Code for Serverless Architectures

Infrastructure as Code (IaC) is a methodology for managing and provisioning infrastructure through machine-readable definition files, rather than physical hardware configuration or interactive configuration tools. This approach is particularly well-suited for serverless architectures, which rely on third-party services to manage the underlying infrastructure.

One of the primary benefits of using IaC for serverless architectures is that it enables consistent and repeatable deployments. By defining infrastructure in code, it is possible to version control and review changes to infrastructure in the same way as application code. This makes it easier to track changes, roll back to previous versions, and ensure that infrastructure is deployed consistently across different environments.

Another benefit of IaC is that it enables automation of infrastructure deployments. This can significantly reduce the time and effort required to provision and configure infrastructure, as well as reduce the risk of errors due to manual configuration.

There are several tools available for implementing IaC in serverless architectures. Some of the most popular include AWS CloudFormation, Azure Resource Manager (ARM) templates, and Google Cloud Deployment Manager templates. These tools allow you to define infrastructure as code using a declarative language, which specifies the desired state of the infrastructure. The tool then takes care of provisioning and configuring the infrastructure to match the specified state.

Here is an example of an AWS CloudFormation template that defines a simple serverless architecture consisting of an API Gateway, Lambda function, and DynamoDB table:

Resources:
  MyApi:
    Type: AWS::ApiGateway::RestApi
    Properties:
      Name: MyApi

  MyFunction:
    Type: AWS::Lambda::Function
    Properties:
      FunctionName: MyFunction
      Handler: index.handler
      Role: !GetAtt MyRole.Arn
      Code:
        ZipFile: |
          var AWS = require('aws-sdk');
          var dynamodb = new AWS.DynamoDB();
          exports.handler = function(event, context, callback) {
            var params = {
              TableName: 'MyTable',
              Key: {
                id: {
                  S: event.pathParameters.id
                }
              }
            };
            dynamodb.getItem(params, function(err, data) {
              if (err) {
                callback(err);
              } else {
                callback(null, {
                  statusCode: 200,
                  body: JSON.stringify(data.Item)
                });
              }
            });
          };
      Runtime: nodejs12.x
      Timeout: 15

  MyRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: sts:AssumeRole
      Policies:
        - PolicyName: MyPolicy
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action:
                  - dynamodb:GetItem
                Resource: !GetAtt MyTable.Arn

  MyTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: MyTable
      AttributeDefinitions:
        - AttributeName: id
          AttributeType: S
      KeySchema:
        - AttributeName: id
          KeyType: HASH
      ProvisionedThroughput:
        ReadCapacityUnits: 5
        WriteCapacityUnits: 5

  MyApiResource:
    Type: AWS::ApiGateway::Resource
    Properties:
      RestApiId: !Ref MyApi
      ParentId: !GetAtt 
        - MyApi
        - RootResourceId
      PathPart: '{id}'

  MyApiMethod:
    Type: AWS::ApiGateway::Method
    Properties:
      RestApiId: !Ref MyApi
      ResourceId: !Ref MyApiResource
      HttpMethod: GET
      AuthorizationType: NONE
      Integration:
        IntegrationHttpMethod: POST
        Type: AWS_PROXY
        Uri: !Sub 
          - arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${MyFunction.Arn}/invocations
          - MyFunction: !GetAtt MyFunction.Arn

This template defines an API Gateway with a single resource and method, a Lambda function that retrieves items from a DynamoDB table, and an IAM role that grants the Lambda function permission to access the DynamoDB table.

To deploy this infrastructure, you can use the AWS CLI command aws cloudformation create-stack, passing in the template file and any required parameters. For example:

aws cloudformation create-stack --stack-name MyStack --template-body file://template.yaml

Once the stack has been created, you can use the AWS CLI or the AWS Management Console to view and manage the infrastructure. For example, you can use the aws cloudformation describe-stacks command to view the current state of the stack, or the aws cloudformation update-stack command to update the stack with a new version of the template.

In addition to AWS CloudFormation, there are several other tools available for implementing IaC in serverless architectures. Azure Resource Manager (ARM) templates are similar to AWS CloudFormation templates, and allow you to define infrastructure as code using a declarative language. Google Cloud Deployment Manager templates are also similar, and allow you to define infrastructure as code using either a YAML or JSON format.

conclusion

Infrastructure as Code is a powerful methodology for managing and provisioning infrastructure in serverless architectures. By defining infrastructure as code, it is possible to version control and automate infrastructure deployments, ensuring consistent and repeatable deployments. There are several tools available for implementing IaC in serverless architectures, including AWS CloudFormation, Azure Resource Manager templates, and Google Cloud Deployment Manager templates.