How to Make AWS Lambda Function Change IP Address After Each Invocation?

Prerequisites

Before we dive into the tutorial, make sure you have the following prerequisites:

• An AWS account with the Lambda and VPC services enabled
• A basic understanding of AWS Lambda functions and VPC configurations
• The AWS CLI installed on your machine

Step 1: Create a VPC and Subnet

The first step is to create a VPC and subnet that will be used to allocate IP addresses to your Lambda function. Follow these steps:

aws ec2 create-vpc --cidr-block 10.0.0.0/16 --output text --query 'Vpc.VpcId'
aws ec2 create-subnet --vpc-id <VPC_ID> --cidr-block 10.0.1.0/24 --output text --query 'Subnet.SubnetId'

Replace `` with the ID of the VPC you created in the previous step.

Step 2: Create an IAM Role and Policy

Next, you need to create an IAM role and policy that will allow your Lambda function to access the VPC and subnet. Follow these steps:

aws iam create-role --role-name lambda-vpc-role --assume-role-policy-document file://trust-policy.json
aws iam create-policy --policy-name lambda-vpc-policy --policy-document file://policy.json
aws iam attach-role-policy --role-name lambda-vpc-role --policy-arn arn:aws:iam::123456789012:policy/lambda-vpc-policy

Create a file called `trust-policy.json` with the following contents:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "lambda.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}

Create a file called `policy.json` with the following contents:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "ec2:DescribeNetworkInterfaces",
      "Resource": "*"
    },
    {
      "Effect": "Allow",
      "Action": "ec2:CreateNetworkInterface",
      "Resource": "*"
    },
    {
      "Effect": "Allow",
      "Action": "ec2:DeleteNetworkInterface",
      "Resource": "*"
    }
  ]
}

Step 3: Create a Lambda Function

Now, create a Lambda function that will use the IAM role and policy created in the previous step. Follow these steps:

aws lambda create-function --function-name lambda-vpc-function --runtime nodejs14.x --role arn:aws:iam::123456789012:role/lambda-vpc-role --handler index.handler --zip-file file:// lambda-function.zip

Create a file called `lambda-function.zip` that contains your Lambda function code. For this example, we’ll use a simple Node.js function that logs the IP address of the function:

exports.handler = async (event) => {
  const https = require('https');
  const os = require('os');

  const interfaceOpts = {
    SubnetId: '',
    Description: 'Lambda VPC Interface'
  };

  const ec2 = new AWS.EC2({ region: 'us-west-2' });
  const params = {
    DryRun: false
  };

  try {
    const data = await ec2.createNetworkInterface(interfaceOpts).promise();
    const params = {
      NetworkInterfaceId: data.NetworkInterface.NetworkInterfaceId
    };

    const allocation = await ec2.allocateAddress(params).promise();
    const ip = allocation.PublicIpAddress;

    console.log(`IP Address: ${ip}`);

    return { statusCode: 200, body: `IP Address: ${ip}` };
  } catch (err) {
    console.error(err);
    return { statusCode: 500, body: `Error: ${err}` };
  }
};

Replace `` with the ID of the subnet you created in Step 1.

Step 4: Configure the Lambda Function to Change IP Address

Finally, configure the Lambda function to change its IP address after each invocation. You can do this by adding a environment variable to the function that specifies the `ENI` (Elastic Network Interface) to use:

aws lambda update-function-configuration --function-name lambda-vpc-function --environment-variables ENI=eni-12345678

Replace `eni-12345678` with the ID of the ENI created by the Lambda function in the previous step.

Testing the Lambda Function

To test the Lambda function, invoke it using the AWS CLI:

aws lambda invoke --function-name lambda-vpc-function --payload '{}' response.json

This will invoke the Lambda function and log the IP address of the function to the console. If you invoke the function multiple times, you should see a different IP address each time.

Conclusion

In this article, we’ve shown you how to make your AWS Lambda function change its IP address after each invocation using a VPC and subnet. This adds an extra layer of security and flexibility to your serverless architecture, allowing you to scale more efficiently and access external services that have IP-based restrictions.

Remember to update the IAM role and policy to include the necessary permissions for your Lambda function to access the VPC and subnet. Also, make sure to test your Lambda function thoroughly to ensure that it’s working as expected.

By following these steps, you can create a secure and scalable serverless architecture that takes advantage of the power of AWS Lambda.

Frequently Asked Question

Are you tired of using the same old IP address for your AWS Lambda function? Do you want to know the secret to making it change IP addresses with each invocation? Look no further! Here are the answers to your burning questions:

Now you know the secrets to making your AWS Lambda function change IP addresses after each invocation! It’s time to get creative and take control of your IP addresses!