Server Load Balancer:ALB access logs

Billing

After ALB ships logs to Simple Log Service, Simple Log Service charges you for storage space, read traffic, the number of requests, data transformation, and data shipping. For more information, see Simple Log Service billing.

Prerequisites

Before you use the access log feature, you must activate Simple Log Service. For more information, see Activate Simple Log Service.

Create an access log

1. Log on to the ALB console.

2. In the top navigation bar, select the region where the ALB instance is deployed.

3. On the Instances page, click the target instance ID.

4. On the instance details page, click the Access Logs tab, and on the Access Logs tab, click Create Access Log.

5. In the Create Access Log dialog box, configure the Project and Logstore parameters, and click OK.

   Configuration	Description
   Project	A resource management unit in Simple Log Service used for resource isolation and control. Select Project: Select an existing Project from the drop-down list. Create Project: Enter a new Project name in the text box.
   Logstore	A unit for log data collection, storage, and query in Simple Log Service. Select Existing Logstore: Select a Logstore from the drop-down list. Create Logstore: Enter a Logstore name in the text box. If you select Create Project, you must also select Create Logstore.
   Notes On Creating Service-linked Role	When you perform this operation, the system automatically creates a service-linked role to enable the feature.

6. In the dialog box that appears, read the information and click OK.

   • If you create a new Logstore, Simple Log Service creates an index and enables a dashboard for the Logstore by default.

   • If you select an existing Logstore, Simple Log Service automatically enables a dashboard. If the Logstore already has an index, the existing configuration is not overwritten. You can add a new index in the Simple Log Service console.

View access logs

1. On the Access Logs tab, click the link on the right side of Simple Log Service to view information such as raw logs in the Simple Log Service console.

2. On the Access Logs tab, click Monitoring Center, Access Center, or Fine-grained Monitoring and specify filter conditions to query metrics.

   Module Classification	Metric description
   Monitoring Center	Displays real-time monitoring data for the ALB instance. Metrics include page views (PVs), request success rate, average latency, 4xx requests, status distribution, traffic, P50 latency, P90 latency, P99 latency, P9999 latency, top request hosts, top latency hosts, top failure rate hosts, top request URLs, top latency URLs, top failure rate URLs, top request backends, top latency backends, and top failure rate backends.
   Access Center	Displays access status data for the ALB instance. Metrics include PVs (day-over-day), PVs (week-over-week), UVs (day-over-day), UVs (week-over-week), PV distribution, UV distribution, today's PVs, 7-day PVs, top 10 accessed provinces, mobile client ratio, top 10 accessed hosts, top 10 accessed UserAgents, and top accessed IPs.
   Second-level Monitoring	Displays monitoring information at a second-level granularity to help identify transient jitter and other exceptions. Metrics include queries per second (QPS), access latency, upstream latency, success rate, request traffic, response body traffic, 2xx status codes, 3xx status codes, error status codes, upstream 2xx status codes, upstream 3xx status codes, and upstream error status codes.

   • In the upper-right corner of the Monitoring Center, Access Center, or Fine-grained Monitoring tab, click More Charts to open the CloudLens for ALB page and view more ALB reports. For more information, see View reports.

   • In the upper-right corner of the Monitoring Center, Access Center, or Fine-grained Monitoring tab, you can click Configure Alert Rules to open the CloudLens for ALB page and view alert incidents for the ALB instance.

   • You can also use the following features in the upper-right corner of the Monitoring Center, Access Center, or Fine-grained Monitoring tabs:

     • : Enables Dedicated SQL. For more information, see High-performance and high-precision query and analysis (Dedicated SQL).

     • After Simple Log Service collects access logs, you can perform operations such as query and analysis, download, data shipping, data transformation, and alert creation. For more information, see General operations for cloud service logs.

Record custom headers

In addition to common headers, the slb_headers field records the names and values of other headers in a request. This allows for complete request logging and improved log analysis.

The custom header in an access log has a default length of 1 KB and can be increased to a maximum of 4 KB. To request an increase, contact your account manager. For more information, see What are the length limits for requests forwarded by ALB? Can they be adjusted?.

1. On the Access Logs tab, in the Basic Information section, click Record Custom Headers.

2. In the Record Custom HTTP Headers in Logs dialog box, select the listener that is associated with the ALB instance from the drop-down list.

   To create a listener, click Create Listener from the drop-down list. For more information, see Add an HTTP listener, Add an HTTPS listener, and Add a QUIC listener.

3. In the dialog box, confirm the information and click OK.

   After the configuration is complete, the slb_headers field in the log records the header_name and header_value of all headers in the request except for the following:

   # Information about the following fields is not recorded in custom headers
   host
   referer
   user-agent
   x-forwarded-for
   x-readtime
   x-real-ip
   uber-trace-id
   X-B3-TraceId
   X-B3-SpanId
   X-B3-ParentSpanId
   X-B3-Sampled

Delete logs

1. On the Access Logs tab, click Disable Logging in the Basic Information section.

2. In the dialog box, confirm the information and click OK.

Log field descriptions

FAQ