If you use a domain name to accelerate a service, you must configure DNS to map the accelerated domain name to the CNAME address that is allocated by the Global Accelerator instance. This topic describes how to add a CNAME record for a domain name using Alibaba Cloud DNS.
Prerequisites
You have created a standard Global Accelerator instance, and configured an acceleration area, a listener, and an endpoint group for the Global Accelerator instance. For more information, see the following topics:
Step 1: Obtain the CNAME of the domain name that you want to accelerate
Log on to the GA console.
On the Instances page, find the Global Accelerator instance that you want to manage and click the instance ID.
Click the Instance Information tab.
In the Basic Information section, find CNAME and click Copy to the right of the CNAME value.
Step 2: Add a CNAME record
Log on to the Alibaba Cloud DNS console.
If your domain name is not registered with Alibaba Cloud Domain Names, you must add your domain name to the Alibaba Cloud DNS console.
NoteIf your domain name is not registered using Alibaba Cloud Domains, you must add your domain name to Alibaba Cloud DNS before you can configure a DNS record. For more information, see Add a domain name. If your domain name is registered using Alibaba Cloud Domains, skip this step.
On the Public Authoritative DNS Resolution page, find the domain name that you want to manage and click DNS Settings in the Actions column.
On the DNS Settings page, click Add DNS Record.
In the Add Record panel, add a CNAME record based on the following information, and then click OK.
For more information about configuring a CNAME record, see CNAME record.
Configuration
Description
Record Type
Select CNAME.
Hostname
Enter the prefix of the accelerated domain name.
If your accelerated domain name is
www.aliyun.com, the host record iswww.If your accelerated domain name is
aliyun.com, the host record is@.If your accelerated domain name is
*.aliyun.com, the host record is*.If your accelerated domain name is
mail.aliyun.com, the host record ismail.
DNS Request Source
Keep the default value.
TTL
Indicates the cache time of DNS records on DNS servers. The smaller the value, the faster the modified records take effect globally.
This topic uses the default value of 10 minutes.
Record Value
Paste the CNAME value that you copied in Step 1: Obtain the CNAME address of the accelerated domain name.
If you want to return resolution results based on the region where a client resides, make sure that Alibaba Cloud DNS is upgraded to Enterprise Standard Edition or Enterprise Ultimate Edition. For more information, see the Upgrade section of the Renewal and upgrade topic.
After the upgrade is complete, you can change the default resolution line of an existing A record to a specific regional resolution line and add a CNAME record that points to the CNAME address assigned by the Global Accelerator instance.
If the backend service type of the endpoint is a custom domain name, the actual amount of time it takes for the DNS record to take effect depends on the following factors:
The TTL value for DNS server caching: You can specify the value when you configure DNS records.
The TTL value for GA caching: By default, GA obtains DNS records every 15 seconds.
Step 3: Check whether the CNAME record takes effect
View the regions where the CNAME record takes effect
Log on to the GA console.
On the Instances page, find the target Global Accelerator instance and click View DNS Records in the CNAME column.
On the Network Probe Tool page, you can view the CNAME resolution results.
After you navigate to the Network Probe Tool page, the default detection points used to initiate network probes depend on the acceleration area configuration:
If the acceleration area contains only regions in the Chinese mainland, the system uses the detection points in each region.
If the acceleration area contains only regions outside the Chinese mainland, the system uses the detection points in each region.
If the acceleration area contains regions inside and outside the Chinese mainland, or contains China (Hong Kong), the system uses all detection points.
You can select the Internet service provider (ISP) and region to perform instant detection as needed.
You can view the resolution result of each detection point. If the resolution result is the same as the accelerated IP address in the acceleration area, it indicates that the CNAME record takes effect in the region.
Check whether the CNAME record takes effect
Automated Authentication Using a Network Probe Tool
Click Instant Detections to go to the Instant Detections page.
On the DNS Tests tab, select a carrier and region, enter an accelerated domain name, and then click Test Now.
In the Probe Check Result section below, click
to the right of the Detection Point City column, enter the name of the accelerated region, and then click Confirm.View the detection result.
If the resolution result for the detection point matches the CNAME value or accelerated IP address of Global Accelerator, it indicates that the CNAME configuration has taken effect.
Use a CLI
Open Command Prompt on a client in the region where the access point is located.
In this topic, the Alibaba Cloud Linux 3 system is used as an example.
Run the ping command to ping the accelerated domain name.
If the returned resolution result is the same as the CNAME value provided by Global Accelerator, the CNAME record has taken effect.
References
To learn how to configure Global Accelerator to accelerate access to the backend service of a specific domain name, see Accelerate access to the backend service of a specific domain name.
For information about how to test the acceleration performance, see Test the acceleration performance of GA.