How will you make Aurora to communicate with a Lambda?

Step 1:

Create an IAM policy as follows:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowAuroraToLambdaFunction",
            "Effect": "Allow",
            "Action": "lambda:InvokeFunction",
            "Resource": "arn:aws:lambda:<REGION>:<ACCOUNT_NO>:function:<FUNCTION_NAME>"
        }
    ]
}

Step 2:

Create an IAM role and attach the policy above and have the trust policy as follows:

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

Step 3:

Link the above IAM role with the Aurora DB cluster

Step 4:

Allow outbound communication from Aurora Cluster to Lambda Function