AWS Certified Developer - Associate

The access token must be stored securely, both at rest and in transit, and it must be accessible from other AWS accounts with minimal management overhead. AWS Secrets Manager is designed specifically for managing secrets like access tokens and provides built-in encryption using AWS KMS. It also supports resource-based policies that allow access from other accounts, which aligns perfectly with the requirement. Additionally, Secrets Manager automates many aspects of secret management, including rotation, which reduces management overhead compared to other services. This makes AWS Secrets Manager the most appropriate choice.

The best solution is to configure the permissions on the main account's event bus to receive events from all accounts. An Amazon EventBridge rule should be created in each account to send all the EC2 instance lifecycle events to the main account's event bus. Then, within the main account's event bus, an EventBridge rule should be set up to match all EC2 instance lifecycle events and target the SQS queue. This approach leverages EventBridge’s cross-account event sharing capabilities, ensures centralization of event management, and does not introduce unnecessary complexity or inefficiency.

To ensure that only authenticated users can access their own files using Amazon Cognito user pools and identity pools, and to maintain the highest level of security, utilizing IAM policies within the Amazon Cognito identity prefix is the optimal approach. By implementing this IAM policy, each user is restricted to accessing only their personalized folders in Amazon S3, ensuring file security and user-specific access control. This method leverages AWS's built-in security mechanisms, which are robust and reliable, to enforce strict access rules, thereby mitigating potential risks associated with custom-built solutions or additional overhead in managing external tables.

AWS Step Functions is the appropriate service for managing and automating the orchestration of data flows. It allows the execution of business rules in sequence and includes features for error handling and reprocessing of data. This service is designed to build scalable workflows with minimal maintenance, which aligns perfectly with the requirements.

The most likely cause of the issue is that the Lambda function does not have IAM permissions to write to DynamoDB. When AWS Lambda functions interact with other AWS services, appropriate IAM permissions are required. If the Lambda function is able to read from S3 but fails when writing to DynamoDB, it indicates that the function's IAM role may lack the necessary permissions for DynamoDB write operations.