Scenarios
An enterprise application service may have multiple IP addresses that are distributed in data centers provided by different operators and vendors in multiple regions. In this case, a single IP address cannot process the access requests that are sent to the application service. In addition, a load balancing architecture is difficult to build for the application service. To address these challenges, you can use DNS to manage IP addresses in a simplified manner and provide application services for customers. However, DNS cannot identify the availability of IP addresses. As a result, DNS cannot distribute network traffic in time from a customer to an available IP address in the case of system failures or disasters. GTM allows you to perform cross-region load balancing among multiple IP addresses and provides more flexibility when you design a service architecture.
Configure round robin to distribute traffic across regions
If an application service has multiple IP addresses that have equal service, compute, and bandwidth capabilities, you can configure round robin to evenly distribute traffic to these IP addresses. This way, access requests sent to the same application service are shared by multiple IP addresses.
Procedure
1 . Configure global settings.
Configure the global settings for a GTM instance. The Balance Policy parameter must be set to Round Robin.
2 . Configure an address pool.
Configure an address pool for the GTM instance.
3 . Enable health check.
Enable health check for the GTM instance.
4 . Configure an access policy.
Configure an access policy for the GTM instance, as shown in the following figure. This access policy is valid for all application users.
5. Add a CNAME record.
Navigate to the DNS settings page of the domain name of the application, add a CNAME record for the application, as shown in the following figure.
Configure weighted round robin to distribute traffic across regions
If an application service has multiple IP addresses that have different service, compute, and bandwidth capabilities, you can configure a weighting method to distribute traffic to these IP addresses.
Procedure
1 . Configure global settings.
Configure the global settings for a GTM instance. The Balance Policy parameter must be set to Weighted Round Robin.
2 .Configure an address pool.
Configure the weighting of an address pool for the GTM instance.
3 . Enable health check.
Enable health check for the GTM instance.
4 . Configure an access policy.
Configure an access policy for the GTM instance. This access policy is valid for all application users.
5 . Add a CNAME record.
Navigate to the DNS settings page of the domain name of the application, add a CNAME record for the application.