DVA-C02 Development with AWS Services Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  The Lambda function is not configured with enough memory

  Why it's wrong here

  Insufficient memory primarily impacts the computational capacity of the Lambda function, leading to crashes, timeouts, or slow processing if the workload exceeds available resources. However, memory allocation does not directly govern the ability to establish a fundamental network connection to an external resource like an RDS instance. Network connectivity issues are typically related to VPC configuration, security groups, or routing, not the function's allocated memory.

• ✗

  The Lambda function is not using a reserved concurrency limit

  Why it's wrong here

  Reserved concurrency is a control mechanism designed to manage the scaling behavior of a Lambda function, ensuring it has a guaranteed number of concurrent executions or preventing it from exceeding a specific limit. This setting directly affects how many instances of the function can run simultaneously, but it has no bearing on the underlying network configuration or the ability of an individual function invocation to establish a TCP connection to an RDS database. If the limit is reached, new invocations are throttled, not blocked by network errors.

• ✓

  The Lambda function is not attached to the same VPC as the RDS instance

  Why this is correct

  An Amazon RDS MySQL instance is deployed within a private Virtual Private Cloud (VPC) and is not publicly accessible by default, requiring private network access. For a Lambda function to connect to this private RDS instance, it must be configured to operate within the same VPC as the database, or a peered VPC, with appropriate security group rules allowing outbound traffic. Without this explicit VPC configuration, the Lambda function executes in the AWS managed network, lacking the necessary private network interface to reach the RDS endpoint directly, resulting in connection failures.

• ✗

  The Lambda function's execution role lacks RDS permissions

  Why it's wrong here

  The Lambda function's execution role defines the AWS API actions the function is authorized to perform on other AWS services, such as reading from S3 or invoking other Lambda functions. However, connecting to a relational database like RDS involves establishing a TCP connection to the database endpoint and authenticating using database-specific credentials (username and password), not AWS IAM permissions. Therefore, a lack of RDS-related IAM permissions on the execution role would not prevent the underlying network connection from being established, though it might prevent API calls to manage the RDS instance itself.

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