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Torch Log Service

CLB log collection

Collect CLB logs

This topic introduces the features and collection methods related to CLB logs.

Features overview

The Classic Load Balancer (CLB) is a service that distributes incoming traffic to multiple backend servers according to policies. It can expand the system's external service capability, eliminate single points of failure, and thus improve the overall availability of the system. CLB supports log shipping of Layer 7 (HTTP/HTTPS) listener access log data to TLS, making it convenient for users to analyze access logs.

The related configuration is as follows:

Configuration	Description
Log type	CLB access log. Health check log.
Log storage location	Create and manage custom log resources in the TLS console. For details, see Manage CLB log resources. Log project: Access log: Custom Health check: clb-health-check-log (editing and deletion of this log are not supported in the TLS console) Log topic: Access log: Custom Health check: Custom
Log storage period	The default is 30 days.
Log shards	Two shards are preset. Auto split of log topic shards is enabled by default. When write traffic is high, shards are split to meet data write requirements.
Index settings	Indexes are configured automatically.
Log fields	For a detailed list of log fields, see CLB log fields.

Collect CLB logs

For details on billing instructions, usage restrictions, and more, see Access log overview and Health check log overview.

For operations on shipping CLB logs to TLS, see Ship access logs to TLS and Cross-service authorization and create a log project.

CLB log fields

User access log fields

Field	Description
loadbalancer_id	CLB instance ID. This field is included in the log file name, but not in the log file content.
protocol_type	The protocol type of the client request.
time_iso8601	The time and time zone when the access response is completed, in standard ISO format. The ending +08:00 indicates the time zone is UTC plus 8 hours, that is, Beijing time.
remote_addr	Client IP address.
remote_port	Client port number.
eip	Public IP address bound to the CLB instance. This field is only relevant for public network instances; private network instances do not involve this field.
request	Request line.
http_user_agent	User-Agent field in the HTTP protocol header.
http_host	Domain name in the request.
http_referer	Source of the HTTP request.
request_length	Number of bytes in the request received from the client.
ssl_protocol	SSL protocol version. This field is relevant for HTTPS protocol listeners; other protocol listeners do not involve this field.
ssl_cipher	SSL cipher suite. This field is relevant for HTTPS protocol listeners; other protocol listeners do not involve this field.
request_id	The request ID.
connection	Connection ID.
connection_requests	Number of requests successfully established on the connection.
vip	Private network IP address of the CLB instance.
listener_id	Listener ID.
vport	Listener port number.
tcpinfo_rtt	Round-trip time of the TCP connection between CLB and the client, measured in milliseconds.
status	CLB instance response status code, which is the status code returned by CLB to the client.
bytes_sent	Number of bytes in the CLB response packet, that is, the number of bytes sent from CLB to the client.
request_time	CLB response time, which is the request processing time from receiving the first byte from the client to sending the last byte to the client. This is the total time for the client request to reach CLB, CLB forwarding the request to the backend server, the backend server responding with data to CLB, and CLB forwarding the data to the client, measured in seconds.
server_name	Domain name of the matched forwarding rule, which can be a wildcard domain name.
servergroup_id	Backend server group ID.
upstream_addr	IP address and port number of the backend server that processed the request. If the request is an exception, this field records the nginx upstreamID.
upstream_connect_time	Time taken for CLB to establish a TCP connection with the backend server, that is, the time from starting to connect to the backend server to starting to send the HTTP request, measured in seconds.
upstream_header_time	Time taken for CLB to receive the complete HTTP header from the backend server, that is, the time from starting to connect to the backend server to receiving the complete HTTP response header from the backend server, measured in seconds.
upstream_response_time	Backend server response time, which is the total time for the backend request, from starting to connect to the backend server to receiving the complete response from the backend server, measured in seconds.
upstream_status	Backend server response status code, which is the status code returned by the backend server to CLB.

Health check log fields

Field	Description
cause	Reasons for health check failure. This field is included in the health check log when a health check fails.
destination	The destination of the health check, that is, the backend server. The format is: the private IP address of the backend server instance: backend port. For example, 192.168.3.114:80.
domain	The domain name of the forwarding rule. This field is not included in the health check logs of Layer 4 listeners.
instanceId	The ID of the CLB instance.
origion	The source of the health check.
protocol	The protocol type used for the health check, including TCP, UDP, and HTTP.
result	The result of the health check, including success and failure.
time	The time when the health check message was sent, in Beijing time by default, for example, 2021-08-10T17:39:29 +08:00.
url	The URL of the forwarding rule. This field is not included in the health check logs of Layer 4 listeners.

Last updated: 2026.02.05 17:33:07