AWS throttling

The AWS API Gateway constantly checks incoming requests from the SolarWinds Platform against AWS account limits. AWS limits steady-state request rates to 1000 requests per second (RPS) and allows bursts of up to 2000 RPS across all APIs, stages, and methods within an AWS account.

AWS applies throttling to relevant instances and volumes when requests exceed default or custom polling thresholds, or if a single event such as a failed polling request occurs. When throttling is applied, the following results occur:

• AWS blocks incoming API requests.
• AWS returns a 429 HTTP response to the SolarWinds Platform.
• Polling is suspended. Relevant instances and volumes enter an Unknown state — AWS Throttling Applied — until the workload decreases.
• Throttling alerts in the SolarWinds Platform are triggered.
• Users receive email notifications that indicate the number of affected instances and volumes.

When throttling stops, resource statuses are updated and alerts are cleared.

Manage AWS throttling alerts

To help reduce multiple alerts overwhelming the alert list, use the Alert me when AWS throttling is applied for cloud account alert, which aggregates throttling events for instances or volumes into a single alert. The SolarWinds Platform checks CloudWatch each minute for throttled instances and volumes; email notifications are sent when throttling stops.

To always receive alerts per throttled instance and volume, disable the account-level alert and enable the following alerts.

• Alert me when AWS throttling is applied for cloud instance: Disabled by default, this alert checks every minute if throttling is applied to instances. Conditions check for the instance status of Unknown and AWS Throttling applied through EC2 API calls.
  
• Alert me when AWS throttling is applied for cloud volume: Disabled by default, this alert checks every minute if throttling is applied to volumes. Conditions check for the attached volume status of Unknown and AWS Throttling applied through EC2 API calls.