AWS Lambda metric for Concurrent Executions now supports all functions, versions, and aliases
The ConcurrentExecutions metric measures the sum of concurrent executions for a Lambda function at a given point in time. Previously, this metric was emitted as an aggregate metric for all functions in the account, and also for functions that had a reserved concurrency limit specified.
Now, the ConcurrentExecutions metric is emitted for all functions, versions, and aliases. You can use this metric to review usage patterns of your Lambda functions. For example, you can see which functions consume your concurrency limit, track how much concurrency your functions consume on average, and estimate peak traffic for your functions. You can also use this metric to determine the appropriate configuration values for Provisioned Concurrency.
To get started, navigate to the Monitoring tab in the Lambda console where you will see a new graph for ConcurrentExecutions. You can also use the Amazon CloudWatch console to visualize and alarm on the metric for concurrent executions.