How to diagnose an NLB instance and view the diagnosis results - Server Load Balancer

The instance diagnostics feature can diagnose the configurations and status of instances, generate diagnosis reports, and provide suggestions on how to fix anomalies. This topic describes how to diagnose a Network Load Balancer (NLB) instance and view the diagnosis results.

Prerequisites

The first time you use the instance diagnostics feature, Network Intelligence Service (NIS) is activated, and the service-linked role AliyunServiceRoleForNis is automatically created. For more information, see Service-linked roles.
An NLB instance is created. For more information, see Create and manage an NLB instance.

Instance diagnostics

Log on to the NLB console.
In the top navigation bar, select the region where the NLB instance is deployed.
On the Instances page, find the NLB instance that you want to diagnose and click Start Diagnostics in the Instance Diagnostics column.
In the Instance Diagnostics panel, view the progress, summary, and details of the diagnostic task.
- If an anomaly is detected, the relevant diagnostic item is displayed in the Instance Diagnostics panel. You can click the diagnostic item to view the details.
- In the Diagnostic Items section, you can select Show All Diagnostic Items to show all diagnostic items of NLB. You can also view the details about each diagnostic item. For more information about NLB diagnostic items, see the Diagnostic items and details.
- You can also click View Historical Diagnostics in NIS Console at the top of the Instance Diagnostics panel to view more diagnosis details about the NLB instance.
After you view the diagnosis information, click Close.

Diagnostic items and details

Note

The severity levels of the issues are indicated by the following colors:

Blue: critical
Red: major
Orange: minor
Yellow: information
Green: passed

The following table describes the diagnostic items of NLB instances.

Category	Diagnostic item and description
Health Check Diagnostics	Health Check Configuration: checks whether the NLB instance has health checks enabled. Health Check Errors: checks whether the NLB instance encounters health check errors.
Idle Instance Diagnostics	NLB Idle Status: checks whether the NLB instance is associated with a listener. Idle Server: checks whether the NLB instance has a backend server. For more information, see Backend server overview.
Security Policy Diagnostics	Interception by Cloud Firewall: checks whether the elastic IP address (EIP) associated with the NLB instance is blocked by Cloud Firewall. Penalty for Security Control: checks whether the EIP associated with the NLB instance receives a penalty from Alibaba Cloud Security. Anti-DDoS Protection Status: checks whether the EIP associated with the NLB instance is protected by Anti-DDoS services. Cloud Security Interception: checks whether the EIP associated with the NLB instance is blocked by Alibaba Cloud Security.
Cost Diagnostics	Overdue Payments: checks whether the NLB instance has overdue payments. Alerts for Overdue Payments: checks whether alerts for near-due payments are triggered for the NLB instance. For more information, see Overdue payments.
Listener Diagnostics	Listener Status: checks whether the listeners of the NLB are stopped.

Remove an instance from the diagnostic list

Log on to the NIS console.
In the left-side navigation pane, choose Self-service Diagnostics > Instance Diagnostics.
On the Instance Diagnostics page, find the instance that you want to remove and click Delete in the Actions column.
In the message that appears, click OK.

References

Work with instance diagnostics