Creating a VPC Flow Log

Scenarios

A VPC flow log records information about the traffic going to and from a VPC.

Configuration Example

You can use a VPC flow log to collect and analyze the traffic of a specified VPC. This section provides guidance on the entire process in typical scenarios to help you configure and analyze flow logs.

Prerequisites

Ensure that the following operations have been performed on the LTS console:

Create a log group.
Create a log stream.

For more information about the LTS service, see the Log Tank Service User Guide.

Procedure

Go to the VPC flow log list page.

In the upper right corner, click Create Flow Log. On the displayed page, configure parameters as prompted.

**Table 1** Parameter descriptions
Parameter	Description	Example Value
Name	The VPC flow log name. The name: Can contain 1 to 64 characters. Can contain letters, digits, underscores (_), hyphens (-), and periods (.).	flowlog-495d
Resource Type	Type of the resource whose traffic is to be logged. The options can be one of the following: NIC Subnet VPC	NIC
Resource	The specific resource whose traffic is to be logged. NOTE: We recommend that you select an ECS in the running state. If an ECS in the stopped state is selected, restart the ECS after creating the VPC flow log for accurately recording the information about the traffic of the ECS's network interface.	N/A
Filter	All traffic: Both accepted and rejected traffic of the specified resource will be logged. Accepted traffic: Only accepted traffic of the specified resource will be logged. Accepted traffic refers to the traffic allowed by the security group and network ACL. Rejected traffic: Only rejected traffic of the specified resource will be logged. Rejected traffic refers to the traffic denied by the security group and network ACL.	All
Log Group	The log group created in LTS.	lts-group-abc
Log Stream	The log stream created in LTS.	lts-topic-abc
Description	Supplementary information about the VPC flow log. This parameter is optional. The VPC flow log description can contain a maximum of 255 characters and cannot contain angle brackets (< or >).	N/A

Only two flow logs, each with a different filter, can be created for a single resource under the same log group and log stream. Each VPC flow log must be unique.