Alibaba Cloud DNS:Address pool configuration

What is address pool configuration

An address pool is a feature of GTM that manages addresses for application services. It represents a group of IP addresses or domain name addresses that provide the same application service with identical carrier or regional properties. A GTM instance can be configured with multiple address pools, enabling users from different regions to access different address pools for proximity access. When an entire address pool collection becomes unavailable, failover can be implemented. Address pool configuration includes address pool name, address pool type, load balancing policy, input address, address region correction, address working mode, and other related information.

Address pool configuration parameter description

1. Address pool name

   Configure an easy-to-remember and identifiable address pool name. You can enter Chinese, English, or other names that are easy for you to identify and remember, such as "test". In the access policy, the address pool accessed by users is also identified by the address pool name.

2. Address pool type

   Address pool types support three options: IPV4, IPV6, or domain name.

   Note

   The commonly used address pool type is IP format. However, because user services might also be CDN addresses, anti-DDoS, firewall, or other domain names, we also provide domain name address pool types. When an address pool contains multiple domain names, the load balancing policy only supports returning addresses by weight.

3. Load balancing policy

   Currently supports Return All Addresses and Return Addresses By Weight.

   When you select Return addresses by weight, the weight configuration option will be available when adding IP addresses to the address pool.

   Address weight: This allows you to configure weights for IP addresses in the address pool. In DNS query requests, GTM will return the corresponding IP addresses according to the preset weights, implementing weighted traffic distribution. You can set load balancing policies separately for address pools and addresses.

   Address pool	Address	Supported
   Return addresses by weight	Return addresses by weight	Supported
   Return all addresses	Return addresses by weight	Not supported. After configuration, the "Return addresses by weight" policy in the address becomes invalid, and the "Return all addresses" policy of the address pool takes effect
   Return all addresses	Return all addresses	Supported
   Return addresses by weight	Return all addresses	Not supported. After configuration, the "Return all addresses" policy in the address becomes invalid, and the "Return addresses by weight" policy of the address pool takes effect

   Note

   Access policies based on access latency do not support load balancing policy settings.

   Weight calculation rules:

   If both the address pool and address load balancing policies are set to "Return by weight", the final address weight = address pool weight value × address weight value

   1. If the address pool and address weights are configured as follows, the weight value of IP 1.1.1.*1 = 2 × 4 = 8.

   Address pool	PoolA	PoolB
   Address pool weight	4	2
   Address	1.1.1.*1	2.2.2.*2
   Address weight	2	3

   2. If the address pool and address weights are configured as follows, where address 1.1.1.*1 exists in both PoolA and PoolB, the weight value of IP 1.1.1.*1 = 2 × 4 + 1 × 1 = 9.

   Address pool	PoolA		PoolB
   Address pool weight	4		1
   Address	1.1.XX.XX	2.2.XX.XX	1.1.XX.XX	3.3.XX.XX
   Address weight	2	3	1	3

4. Address

   The address is entered based on the selected address type. If the address type is IP, enter the IP address corresponding to your application service in the address input box. If the address type is domain name, enter the domain name corresponding to your application service in the address input box.

5. Address region correction

   This refers to the geographic location information of the application server address. After you input an address in the address pool, GTM will automatically locate the geographic location information of the application service address. You can also use the Correction button to change the geographic location of the application service address.

   Note

   If the address pool type is domain name, you must manually correct the address region.

   

6. Address working mode

   When entering an IP in the address input box, you can also set different address working modes for the IP. Address working modes include three types:

• Smart return: The default enabled working mode. It dynamically selects IP addresses based on health check status. When the IP address health check is normal, DNS resolution returns the IP address to users. When the IP address is abnormal, the system will temporarily remove the abnormal IP address.

• Always online: In this working mode, the system will consider the IP address to always be in a normal state. DNS resolution will always return this IP address to users. Health checks monitor and alert for always online IP addresses but do not execute IP address removal, addition, or failover actions after alerts.

• Always offline: The system considers this IP address to always be in an abnormal state. DNS resolution will not return this IP address to users. This IP address only exists in the system configuration, waiting to be enabled at a later time. Health checks monitor and alert for always offline IP addresses but will not execute IP address removal, addition, or failover actions after alerts.

7. Add a row & Batch add

   Add addresses in single or multiple ways.

Address pool operation instructions

1. Add address pool

   This refers to adding a new address pool, including settings for address pool name, address pool type, load balancing policy, input address, address region correction, and address working mode.

   Note

   • Standard Edition instances can add up to 10 access address pools.

   • Ultimate Edition instances can add up to 20 access address pools.

2. Modify

   Edit an existing address pool. This includes editing and modifying the address pool name, address pool type, load balancing policy, input address, address region correction, and address working mode.

3. Delete

   Delete an existing address pool. However, if the address pool already has associated access policies, you need to delete the associated access policies first before you can delete the address pool.

4. Health check

   When enabled, it can monitor the availability status of application services in real time, including configuration related to PING monitoring, TCP monitoring, and HTTP(s) monitoring. For more information, see Enable health check.

Configuration methods

1. Log on to Cloud DNS-Global Traffic Manager.

2. Go to the instance list page of Global Traffic Manager, click the target instance, and on the global configuration page, select the Address Pool Configuration tab, and click the Add Address Pool button.

   

3. After clicking the Add Address Pool button, enter the address pool name, address pool type, load balancing policy, address, address region, address weight, address working mode, and other information in the dialog box, and finally click the Confirm button.

4. After adding the address pool, you can view the related configuration of the address pool on the Address Pool Configuration page.

   

Feature rules

1. Maximum number of address pools that can be created per instance: 10 for Standard Edition and 20 for Ultimate Edition.

2. Each address pool can add a maximum of 20 addresses (IP or domain name).

3. The address pool weight can only be configured if the load balancing policy in the GTM instance's address pool collection configuration is set to return addresses by weight.

4. Without health checks enabled, the address pool availability status is based on the address working mode setting (Smart return/Always online represents normal, Always offline represents abnormal).

5. Address pools that are already applied in access policies cannot be directly deleted. You need to modify or delete the access policy in the access policy configuration first, and then delete the address pool on the address configuration page.