Server Load Balancer:Access logs

Billing

After the access logs of ALB are delivered to Simple Log Service, you are charged for data storage, read traffic, requests, data transformation, and data shipping. For more information, see Billable items of pay-by-feature.

Prerequisites

Simple Log Service is activated. For more information, see Activate Simple Log Service.

Enable the access log feature

1. Log on to the ALB console.

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

3. On the Instances page, click the ID of the ALB instance that you want to manage.

4. On the Instance Details tab, click the Access Logs tab. 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.

   Parameter	Description
   Project	Select the Simple Log Service project that you want to use to isolate and manage resources. Valid values: Select Project: Select an existing project from the drop-down list. Create Project: Enter a project name in the field.
   Logstore	Select the Logstore that you want to use to collect, store, and query log data in Simple Log Service. Valid values: Select Logstore: Select an existing Logstore from the drop-down list. Create Logstore: Enter a Logstore name in the field. If you select Create Project, select Create Logstore.
   Notes on Creating Service-linked Role	After you perform this operation, a service-linked role is automatically created.

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

   • If you create a Logstore, indexes and dashboards are created and enabled for the Logstore by default.

   • If you select an existing Logstore, dashboards are automatically enabled for the Logstore. Existing indexes of the Logstore are not overwritten. You can create indexes 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 go to the Simple Log Service console to view log data.

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

   Module	Description
   Monitoring Center	Displays the real-time monitoring data of the ALB instance. The metrics include PVs, Request Success Rate, Average Latency, Requests with Status Code 4xx, Status Distribution, Traffic, P50 Latency, P90 Latency, P99 Latency, P9999 Latency, Hosts with Most Requests, Hosts with Highest Latency, Hosts with Highest Failure Rate, URLs with Most Requests, URLs with Highest Latency, URLs with Highest Failure Rate, Backends with Most Requests, Backends with Highest Latency, and Backends with Highest Failure Rate.
   Access Center	Displays the access information about the ALB instance. The metrics include PVs (Day-on-day), PVs (Week-on-week), UVs (Day-on-day), UVs (Week-on-week), PV Distribution, UV Distribution, PVs Today, PVs of 7 Days, Top 10 States with Most Requests, Percentage of Mobile Users, TOP 10 Hosts with Most Requests, TOP 10 User Agents with Most Requests, and IP Addresses with Most Requests.
   Fine-grained Monitoring	Displays the metrics that are aggregated at one-second intervals. You can use the metrics to identify exceptions that are related to transient jitters. The metrics include QPS, Access Latency, Upstream Latency, Success Rate, Request Traffic, Response Body Traffic, Status Code 2xx, Status Code 3xx, Error Codes, Upstream Status Code 2xx, Upstream Status Code 3xx, and Upstream Error Codes.

   • In the upper-right corner of the Monitoring Center, Access Center, or Fine-grained Monitoring tab, you can click More Charts to go to the CloudLens for ALB page to 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 go to the CloudLens for ALB page to view alert incidents of ALB.

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

     • : enables Dedicated SQL. For more information, see Enable Dedicated SQL.

     • After access logs are delivered to Simple Log Service, you can query, analyze, download, deliver, and process the access logs. You can also create alert rules for the access logs. For more information, see Common operations on logs of Alibaba Cloud services.

Record custom headers

slb_headers can record the names and values of custom request headers. You can use the data to analyze requests.

The maximum size of custom headers that can be recorded in an access log is 1 KB. If the size of custom headers exceeds the limit, the excess part is truncated. You cannot increase the allowed maximum size. For more information, see What is the maximum size of a request that can be forwarded by an ALB instance? Can I increase the allowed maximum size?

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

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

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

3. In the message that appears, read the information and click OK.

   After the configuration is complete, the slb_headers field is added to access logs to record the names and values of all headers in a request except the following headers:

   # The slb_headers field does not record information about the following 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

Disable the access log feature

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

2. In the message that appears, read the information and click OK.

Log fields