Creates a flow log.

Operation description

Flow logs are used to capture the information about network traffic between transit routers and between virtual border routers (VBRs). Before you create a flow log, take note of the following items:

Flow logs are supported only by Enterprise Edition transit routers.
Only flow logs in some regions can capture the information about network traffic over VBR connections. For more information, see Limits .
Flow logs are used to capture the information about outbound traffic on transit routers. Information about inbound traffic on transit routers is not captured.

For example, an Elastic Compute Service (ECS) instance in the US (Silicon Valley) region accesses an ECS instance in the US (Virginia) region through CEN. After you enable the flow log feature for the transit router in the US (Virginia) region, you can check the log entries about packets sent from the ECS instance in the US (Virginia) region to the ECS instance in the US (Silicon Valley) region. However, packets sent from the ECS instance in the US (Silicon Valley) region to the ECS instance in the US (Virginia) region are not recorded. If you want to record the packets sent from the ECS instance in the US (Silicon Valley) region to the ECS instance in the US (Virginia) region, you must also enable the flow log feature on the transit router that is in the US (Silicon Valley) region.
CreateFlowLog is an asynchronous operation. After you send a request, the system returns a flow log ID and runs the task in the background. You can call the DescribeFlowLogs operation to query the status of a flow log.
- If a flow log is in the Creating state, the flow log is being created. In this case, you can query the flow log but cannot perform other operations.
- If a flow log is in the Active state, the flow log is created.

Prerequisites

An inter-region connection or a VBR connection is created. For more information, see CreateTransitRouterPeerAttachment or CreateTransitRouterVbrAttachment .

Debugging

You can run this interface directly in OpenAPI Explorer, saving you the trouble of calculating signatures. After running successfully, OpenAPI Explorer can automatically generate SDK code samples.

Debug

Authorization information

The following table shows the authorization information corresponding to the API. The authorization information can be used in the Action policy element to grant a RAM user or RAM role the permissions to call this API operation. Description:

Operation: the value that you can use in the Action element to specify the operation on a resource.
Access level: the access level of each operation. The levels are read, write, and list.
Resource type: the type of the resource on which you can authorize the RAM user or the RAM role to perform the operation. Take note of the following items:
- The required resource types are displayed in bold characters.
- If the permissions cannot be granted at the resource level, All Resources is used in the Resource type column of the operation.
Condition Key: the condition key that is defined by the cloud service.
Associated operation: other operations that the RAM user or the RAM role must have permissions to perform to complete the operation. To complete the operation, the RAM user or the RAM role must have the permissions to perform the associated operations.

Operation	Access level	Resource type	Condition key	Associated operation
cen:CreateFlowlog	create	All Resources *	none	none

Request parameters

Parameter	Type	Required	Description	Example
ClientToken	string	No	The client token that is used to ensure the idempotence of the request. You can use the client to generate the value, but you must make sure that it is unique among all requests. The token can contain only ASCII characters. Note If you do not set this parameter, ClientToken is set to the value of RequestId. The value of RequestId for each API request may be different.	123e4567-e89b-12d3-a456-42665544****
RegionId	string	Yes	The ID of the region where the flow log is deployed. You can call the DescribeChildInstanceRegions operation to query the most recent region list.	cn-hangzhou
FlowLogName	string	No	The name of the flow log. The name must be 2 to 128 characters in length, and can contain digits, periods (.), underscores (_), and hyphens (-). The name must start with a letter but cannot start with `http://` or `https://`.	myFlowlog
Description	string	No	The description of the flow log. The description must be 2 to 256 characters in length. It must start with a letter but cannot start with `http://` or `https://`.	myFlowlog
CenId	string	Yes	The ID of the CEN instance.	cen-7qthudw0ll6jmc****
ProjectName	string	Yes	The Log Service project where the flow log is stored. If a project is already created in the selected region, enter the name of the project. If no projects are created in the selected region, enter a name and the system automatically creates a project. The project name must be unique in a region. You cannot change the name after you create the project. The naming conventions are: The name must be globally unique. The name can contain only lowercase letters, digits, and hyphens (-). The name must start and end with a lowercase letter or a digit. The name must be 3 to 63 characters in length.	FlowLogProject
LogStoreName	string	Yes	The Logstore where the flow log is stored. If a Logstore is already created in the selected region, enter the name of the Logstore. If no Logstores are created in the selected region, enter a name and the system automatically creates a Logstore. The name of the Logstore. The name must meet the following requirements: The name must be unique in a project. The name can contain only lowercase letters, digits, hyphens (-), and underscores (_). The name must start and end with a lowercase letter or a digit. The name must be 3 to 63 characters in length.	FlowLogStore
Interval	long	No	The time window for collecting log data. Unit: seconds. Valid values: 60 and 600. Default value: 600.	600
TransitRouterAttachmentId	string	No	The ID of the inter-region connection or the VBR connection. Note This parameter is required.	tr-attach-r6g0m3epjehw57****
Tag	array<object>	No	The information about the tags. You can specify at most 20 tags in each call.
	object	No
Key	string	No	The tag key. The tag key cannot be an empty string. The tag key can be up to 64 characters in length and cannot start with `acs:` or `aliyun`. It cannot contain `http://` or `https://`. You can specify at most 20 tag keys.	TagKey
Value	string	No	The tag value. The tag value can be 0 to 128 characters in length, and cannot start with `aliyun` or `acs:`. It cannot contain `http://` or `https://`. Each tag key must have a unique tag value. You can specify at most 20 tag values in each call.	TagValue

Response parameters

Parameter	Type	Description	Example
	object	The response.
RequestId	string	The ID of the request.	54B48E3D-DF70-471B-AA93-08E683A1B457
Success	string	Indicates whether the call is successful. Valid values: true: yes false: no	true
FlowLogId	string	The ID of the flow log.	flowlog-m5evbtbpt****

Examples

Sample success responses

JSONformat

{
  "RequestId": "54B48E3D-DF70-471B-AA93-08E683A1B457",
  "Success": "true",
  "FlowLogId": "flowlog-m5evbtbpt****"
}

Error codes

HTTP status code	Error code	Error message	Description
400	ProjectOrLogstoreNotExist	The specified project or logstore does not exist.	The error message returned because the specified project or Logstore does not exist.
400	SourceProjectNotExist	The Source Project or logstore does not exist.	The error message returned because the specified source project or Logstore does not exist.
400	OperationUnsupported.action	This action is not support.	The error message returned because this operation is not supported in the specified region.
400	RuleExist	The rule has already existed.	The rule already exists.
400	QuotaExceeded.FlowlogCount	This user has reached the maximum instance number of flowlog.	The error message returned because the number of flow logs has reached the upper limit.
400	InvalidFlowlogId.exist	This cenId already has flowlog instance existed.	The error message returned because the specified CEN instance is already associated with a flow log.
400	Flowlog.AlreayExist	This attachment already has existed flowlog instance.	The error message returned because the specified flow log already exists. You cannot create duplicate flow logs.
400	IllegalParam.TransitRouterAttachmentId	TransitRouterAttachmentId is illegal.	The error message returned because the specified transit router is invalid.
400	InvalidTransitRouterAttachmentId.NotFound	The TransitRouterAttachmentId is not found.	The error message returned because the specified transit router attachment ID (TransitRouterAttachmentId) does not exist.
400	IncorrectStatus.flowlog	This action is not allowed in the current flow log status.	This action is not allowed in the current flow log status.
400	InvalidOperation.TransitRouterNotExist	Operation is invalid because the transit router not exist.	The error message returned because the specified transit router does not exist.
400	IncorrectStatus.TransitRouterAttachmentId	The resource is not in a valid state for the attachment operation.	The error message returned because the operation is not supported when the specified attachment is in an unstable state
400	ProjectExist	Project already exist, please try a different project name.	The log Project already exists, try a different Project name.
400	InvalidParameter.ProjectName	Project name is invalid or does not belong to specified region.	The Project name is illegal or does not belong to the specified region.
400	IncorrectStatus.TrFlowlog	Flowlog status for specified TransitRouter is invalid for this operation.	Flowlog status for specified TransitRouter is invalid for this operation.
400	OperationInvalid.IncompatibleFlowlogExist	Operation is invalid because incompatible flowlog config exists.	There are incompatible Flowlog configurations, please delete and try again.
400	InvalidParameter.LogFormatString	LogFormatString is invalid.	The specified log format is invalid.
400	InvalidParameter.LogStoreName	Specified LogStore name is invalid.	Logstore name is invalid.
400	InvalidParameter.ProjectName	ProjectName is invalid.	Project name is invalid.
400	OperationFailed.InvalidLogInfo	The entered log service information is invalid. Check whether the ProjectName and LogStoreName are correct, and whether Log Service has been activated.	The entered log service information is invalid. Check whether the ProjectName and LogStoreName are correct, and whether Log Service has been activated.
400	InvalidParameter	Invalid parameter.	The error message returned because the parameter is set to an invalid value.
400	Unauthorized	The AccessKeyId is unauthorized.	The error message returned because you do not have the permissions to perform this operation.
403	NoPermission.AliyunServiceRoleForTRFlowLog	You are not authorized to create service linked role AliyunServiceRoleForTRFlowLog.	You are not authorized to create service linked role AliyunServiceRoleForTRFlowLog.

For a list of error codes, visit the Service error codes.

Change history

Change time	Summary of changes	Operation
2024-07-02	The Error code has changed	View Change Details
2024-05-22	The Error code has changed	View Change Details
2023-01-03	The Error code has changed	View Change Details