What are instances?
On the Global Traffic Manager page of the Alibaba Cloud DNS console, you can view the details of GTM instances. These details include the instance ID, canonical name (CNAME), number of health check tasks, number of alert notifications, status, instance edition, expiration time, and actions.
Overview
GTM allows you to manage the access traffic of your application services by instance in a fine-grained manner. Each instance corresponds to an application service. For example, Instance 1 is used to manage the traffic of the www.dns-example.com service. Instance 2 is used to manage the traffic of the dns-example.com service. Different instances are used to manage different services. This allows you to manage services with ease, use resources on demand, and reduce costs caused by IP address failures.
Purchase an instance
Before you use GTM, you must purchase a GTM instance. For more information, see Create an instance.
Instances
ID/Name
ID: After you purchase a GTM instance, the system automatically generates an instance ID. The instance ID is a unique identifier for the application service corresponding to the instance. You can use the instance ID to perform operations such as upgrading, renewing, and releasing the instance.
Name: When you configure basic settings for a GTM instance, you can specify an informative instance name that is easy to remember and can identify the application service corresponding to the instance.
CNAME
After you purchase a GTM instance, you must assign a CNAME to the GTM instance. Before you use GTM to route access traffic, you must perform the following steps: On the Domain Name Resolution page, click the desired domain name. On the DNS Settings page, click Add DNS Record to add a CNAME record for the domain name to point the domain name to the CNAME.
Health Check Tasks
After you create an address pool and enable the health check feature, the system calculates the number of health check tasks. This number is generated after the system multiplies the number of IP addresses in the address pool by the number of the specified monitoring nodes.
NoteIf the health check feature is not enabled for the address pool, the quota for health check tasks is not calculated.
Standard Edition supports an initial quota of 100. Ultimate Edition supports an initial quota of 100. If the number of health check tasks exceeds the initial quota, you can upgrade the related GTM instance to increase the number of detection tasks.
Use the following formula to calculate the number of health check tasks:
The number of health check tasks = The total number of addresses in an address pool × The total number of monitoring nodes in the address pool
If multiple address pools exist, the number of health check tasks of each address pool adds up to the total number of health check tasks.
Alert Notifications Sent This Month
This parameter indicates the number of alert notifications that were sent in the current month. Standard Edition supports an initial quota of 1,000 alert notifications per month. Ultimate Edition supports an initial quota of 2,000 alert notifications per month. If the number of alert notifications that are sent in a month exceeds the initial quota, you can purchase SMS notifications to increase the quota. Find the required GTM instance and click Upgrade in the Actions column. On the Upgrade/Downgrade page, specify a number that you want to increase in the SMS Notifications field and click Buy Now.
Status
Valid values: Normal and Abnormal.
State
Description
Normal
The health check feature is not enabled for the GTM instance, or the health check result is normal.
Abnormal
The health check feature is enabled for the GTM instance. If an exception is returned by a health check, the GTM instance is deemed abnormal.
Alert notifications include the following metrics:
Number of abnormal addresses
Number of unavailable address pool sets
Number of access policies with traffic switched to secondary address pool sets
Number of access policies with unavailable address pool sets
Instance Edition
The edition of a GTM instance. Valid values: Standard Edition and Ultimate Edition.
Expired At (UTC+8)
The expiration time of a GTM instance. You will receive a notification 1 day, 3 days, and 7 days before the GTM instance expires.
Actions
Settings: You can click Settings in the Actions column to configure basic settings, access policies, address pool sets, and address pools for a GTM instance. You can also enable the health check feature for the GTM instance.
Upgrade: You can upgrade a GTM instance after you click Upgrade in the Actions column. For example, you can upgrade the GTM instance from Standard Edition to Ultimate Edition, increase the number of detection tasks, and increase the number of SMS notifications.
Renew: You must renew a GTM instance before it expires. To ensure business continuity, we recommend that you select Auto-renewal.