AWS Lambda function-level ReservedConcurrentExecutions limit is not set Affecting Lambda service in AWS


Severity

0.0
medium
0
10
    Severity Framework
    Snyk CCSS
    Rule category
    Availability / Limits

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  • Snyk ID SNYK-CC-00745
  • credit Snyk Research Team

Description

Ensure that the function can scale without impacting other resources and maintain predictable performance and cost by defining a specific number of reserved concurrent executions. Omitting or disabling ReservedConcurrentExecutions for AWS Lambda functions can lead to uncontrolled scaling, which may result in throttling, increased latency, or higher costs due to excessive executions.

How to fix?

Set the reserved_concurrent_executions attribute in the aws_lambda_function resource to a positive of at least 1.

Example Configuration

resource "aws_lambda_function" "allowed1_lambda" {
  filename      = "lambda_function_payload.zip"
  function_name = "lambda_function_allowed745"
  role          = aws_iam_role.iam_for_lambda.arn
  handler       = "index.test"

  source_code_hash = data.archive_file.allowed1_file.output_base64sha256

  runtime                        = "nodejs18.x"
  reserved_concurrent_executions = 200
}