What is Global Traffic Manager (GTM) 3.0? _GTM 3.0 - Alibaba Cloud DNS

Overview

Global Traffic Manager (GTM) 3.0 is a new release of GTM. GTM 3.0 supports graphical orchestration configuration, multiple types of health check templates, the combination of varied load balancing policies (Closest to Source, Weight, Order, and Poll), and the combination of various resolution lines. In this way, GTM 3.0 provides flexible and efficient disaster recovery and traffic scheduling solutions for enterprises and performs fine-grained and intelligent management of inbound traffic. Click

here to purchase a GTM 3.0 instance.

Note

GTM returns specific service addresses to users by using a Domain Name System (DNS) resolution service. This way, the users can directly access the service addresses. GTM does not function as a proxy or a gateway device, or provide an application access service. Therefore, the statistics on network traffic between users and application services are not displayed on the Global Traffic Manager 3.0 page.

Features

The following figure shows the features of GTM.

1. Access domain name

GTM uses access domain names to provide services. You can add a canonical name (CNAME) record to map a business domain name to an access domain name. This way, the business domain name can be connected to GTM.

Before you create an access domain name, make sure that at least one primary domain name exists within your Alibaba Cloud account, and that an Internet Content Provider (ICP) filing is obtained for the primary domain name. For example, example.com is the primary domain name within your Alibaba Cloud account.
Enter an access domain name in the format of Hostname.Primary domain name. Example: gtm.example.com. If your business domain name is hosted by Alibaba Cloud DNS, you can set the hostname of the access domain name to that of your business domain name. In this case, your business domain name is also the access domain name.

For more information, see Configure an access domain name.

2. Address pool

GTM allows you to group the IP addresses or domain names that are used to access application services into address pools for management. An address pool contains a group of IP addresses or domain names that are used to access the same application service. The IP addresses or domain names in an address pool belong to the same Internet service provider (ISP) or reside in the same region. You can configure more than one address pools for a GTM instance. This way, requests from different regions can be forwarded to the nearest address pools. If a primary address pool is unavailable, a secondary address pool is used for failover. For more information, see Configure an address pool.

3. Address

Addresses are used to access application services. Addresses are returned by GTM after resolution and decision-making. An address can be a service IP address or a domain name. The Service Port parameter is important for checking service availability during health checks. For more information, see Configure an address.

4. Load balancing policy

As a mechanism for dynamic resource scheduling, a load balancing policy selects an appropriate address in an appropriate address pool for an access domain name based on specific algorithms and policies. GTM 3.0 supports the following types of load balancing policies:

Closest to Source: This policy achieves intelligent resolution. The policy routes traffic from users to the service addresses that reside in the nearest geological locations or belong to the same ISPs by accurately identifying the geological locations or ISPs of the users. This reduces network latency and accelerates responses.
Order: Available address pools or addresses are selected in a preset order. This ensures that available servers are accessed by order.
Poll: Available address pools and addresses are selected in round-robin mode. This ensures that available servers receive almost the same amount of traffic and achieves load balancing. Specifically, an address pool is selected among multiple address pools and all addresses in the address pool are returned in round-robin mode.
Weight: You can set different weight values for addresses and address pools based on the processing capabilities or performance of servers. This way, addresses with larger weight values receive more requests and system resources are efficiently utilized.

The preceding flexible load balancing policies help distribute and manage inbound traffic in an appropriate way.

To adapt to the complex scheduling scenarios of enterprises, GTM 3.0 supports two levels of scheduling based on load balancing policies. The following section describes the principle of two levels of scheduling based on load balancing policies.

First-level scheduling: GTM selects an appropriate address pool for an access domain name based on a configured load balancing policy. For more information, see the Parameters for configuring a policy of load balancing between address pools section of the GTM configuration process topic.
Second-level scheduling: GTM selects an appropriate and available address from the address pool based on a configured load balancing policy and returns the address to the user. For more information, see the Parameters for configuring the policies of load balancing between addresses section of the Configure an address pool topic.

5. Health check template

Health checks are performed mainly on addresses in address pools. The running status and availability of application services are detected and evaluated in real time. The health checks include ping-based monitoring, TCP connection monitoring, and HTTP or HTTPS endpoint monitoring.

GTM 3.0 allows users to configure health check templates based on multiple protocols. This helps evaluate the availability status of application service addresses in a comprehensive way.

Architecture

GTM consists of the control layer and the resolution layer.

The control layer provides services by using the console and API operations. The control layer allows you to add, delete, modify, query, and save DNS resolution data, configuration data, monitoring data, and log data. The control layer is deployed in China (Zhangjiakou).
The resolution layer provides services by using the DNS server clusters that are deployed around the world. The resolution layer receives the DNS record data distributed from the control layer and responds to the queries for the DNS record data. The resolution layer covers the major continents and regions around the world.

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