Reference: ec2messages, ssmmessages, and other API calls - AWS Systems Manager

Reference: ec2messages, ssmmessages, and other API calls

If you monitor API calls, you might see calls to the following APIs:

  • ec2messages:AcknowledgeMessage

  • ec2messages:DeleteMessage

  • ec2messages:FailMessage

  • ec2messages:GetEndpoint

  • ec2messages:GetMessages

  • ec2messages:SendReply

  • ssmmessages:CreateControlChannel

  • ssmmessages:CreateDataChannel

  • ssmmessages:OpenControlChannel

  • ssmmessages:OpenDataChannel

  • ssm:UpdateInstanceInformation

  • ssm:ListInstanceAssociations

  • ssm:DescribeInstanceProperties

  • ssm:DescribeDocumentParameters

These special calls are used by AWS Systems Manager for various operations.

ec2messages API calls

Calls to ec2messages:* APIs are calls to the Amazon Message Delivery Service endpoint. Systems Manager uses this endpoint to make calls from Systems Manager Agent (SSM Agent) to the Systems Manager service in the cloud. This endpoint is required to send and receive commands. For more information, see Actions, Resources, and Condition Keys for Amazon Message Delivery Service.

ssmmessages API calls

Systems Manager uses the ssmmessages endpoint to make calls from SSM Agent to Session Manager, a capability of AWS Systems Manager, in the cloud. This endpoint is required to create and delete session channels with the Session Manager service in the cloud. For more information, see Actions, resources, and condition keys for Amazon Session Manager Message Gateway Service.

Instance-related API calls

UpdateInstanceInformation: SSM Agent calls the Systems Manager service in the cloud every 5 minutes to provide heartbeat information. This call is necessary to maintain a heartbeat with the agent so that the service knows the agent is functioning as expected.

ListInstanceAssociations: The agent calls this API to see if a new State Manager association is available. This API is required for State Manager, a capability of AWS Systems Manager, to function.

DescribeInstanceProperties and DescribeDocumentParameters: Systems Manager calls these APIs to render specific nodes in the Amazon EC2 console. The DescribeInstanceProperties API displays the Fleet Manager node in the left navigation. The DescribeDocumentParameters API displays the Documents node in the left navigation.