Virtual Private Cloud (VPC) provides the flow log feature to record information about inbound and outbound traffic of an elastic network interface (ENI). You can use the flow log feature to check access control list (ACL) rules, monitor network traffic, and troubleshoot network errors.
Feature release and supported regions
|Asia Pacific||China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Hangzhou), China (Shanghai), China (Nanjing - Local Region), China (Fuzhou - Local Region), China (Shenzhen), China (Heyuan), China (Guangzhou), China (Chengdu), China (Hong Kong), Japan (Tokyo), South Korea (Seoul), Singapore, Australia (Sydney), Malaysia (Kuala Lumpur), Indonesia (Jakarta), Philippines (Manila), Thailand (Bangkok), and India (Mumbai)|
|Europe & Americas||Germany (Frankfurt), UK (London), US (Silicon Valley), and US (Virginia)|
|Middle East||UAE (Dubai)|
Flow logs can capture information about network traffic of a specified ENI, VPC, or vSwitch. After you enable the flow log feature for a VPC or a vSwitch, traffic information about ENIs in the VPC or vSwitch is captured. Flow logs also capture traffic information about ENIs that are created after the flow log feature is enabled.
The traffic information captured by the flow log feature is written to Log Service as flow log entries. Each flow log entry includes a 5-tuple of a traffic flow captured within the capture window. The capture window is approximately 10 minutes. During the capture window, traffic information is captured and aggregated into a flow log entry.
|version||The version of the flow log.|
|vswitch-id||The ID of the vSwitch to which the ENI belongs.|
|vm-id||The ID of the Elastic Compute Service (ECS) instance with which the ENI is associated.|
|vpc-id||The ID of the VPC to which the ENI belongs.|
|account-id||The ID of the Alibaba Cloud account.|
|eni-id||The ID of the ENI.|
|srcaddr||The source IP address.|
|srcport||The source port.|
|dstaddr||The destination IP address.|
|dstport||The destination port.|
|protocol||The Internet Assigned Numbers Authority (IANA) protocol number of the traffic.
For more information, see Protocol Numbers.
|direction|| The direction of the traffic. Valid values:
|packets||The number of data packets.|
|bytes||The size of data packets.|
|start||The start time of the capture window.|
|end||The end time of the capture window.|
|log-status||The logging status of the flow log. Valid values:
|action|| The action that was performed on the traffic flow. Valid values:
Billing and pricingFor more information about the billing of flow logs, see Billing of flow logs.
|Maximum number of flow logs that can be created in each region||10||No quotas|
|ECS instance families that do not support flow logs||
Upgrade the ECS instances that do not support flow logs. For more information, see Upgrade the instance types of subscription instances and Change the instance type of a pay-as-you-go instance.
- Activate Log Service
The traffic information captured by the flow log feature is stored in Log Service. You must activate Log Service before you create a flow log.
- Optional. Create an AccessKey pair
If you want to write data by using an API or SDK, you must create an AccessKey pair. If you want to collect logs by using Logtail, you do not need to create an AccessKey pair.
- Create a project
You must create a project in Log Service. For more information, see Create a project.
- Create a Logstore
A Logstore is a collection of resources in a project. All data in a Logstore is retrieved from the same source. After you create a project, you must create a Logstore. For more information, see Create a Logstore.
- Specify a resource from which traffic information is captured
Before you create a flow log, you must specify the resource from which traffic information is captured. You can capture traffic information from an ENI, VPC, or vSwitch. For more information, see Create an ENI, Create and manage a VPC, and Create and manage a vSwitch.
- Create a flow log
You can create a flow log to capture information about inbound and outbound traffic of ENIs in a VPC. For more information, see Create and manage a flow log.
- View flow logs
After you create a flow log, you can view the flow log. You can analyze inter-region data transmission, control data transfer costs, and troubleshoot network issues based on the captured traffic information.