Global Accelerator:Accelerate access to a backend service with a specific domain name

Scenarios

The following scenario is used as an example in this topic. A company that is headquartered in the US (Silicon Valley) region deployed a web service on two self-managed servers. The web service can be accessed through the domain name www.example.com and port 80. When users from the office in the China (Shenzhen) region connect to the web service deployed in the US (Silicon Valley) region over the Internet, the network condition is unstable. Issues such as high network latency, network jitter, and packet loss occur.

You can configure a Global Accelerator instance to forward traffic from users in the China (Shenzhen) region to the access point in the China (Shenzhen) region through an accelerated IP address. Then, GA forwards the requests to the global transmission network of Alibaba Cloud and uses intelligent routing to route the requests to the endpoints in the US (Silicon Valley) region. This accelerates access and improves user experience.

Prerequisites

Step 1: Configure basic information about an instance

1. Log on to the GA console.

2. On the Instances page, click Create Standard Pay-as-you-go Instance.

3. In the Basic Instance Configuration step, configure the following parameters and click Next.

   Parameter	Description
   GA Instance Name	Enter a name for the GA instance.
   Instance Billing Method	Pay-As-You-Go is selected by default. You are charged instance fees, Capacity Unit (CU) fees, and data transfer fees for pay-as-you-go standard Global Accelerator instances. For more information about instance fees and CU fees, see Billing of pay-as-you-go GA instances. For more information about data transfer fees, see Pay-by-data-transfer.
   Resource Group	Select the resource group to which the standard Global Accelerator instance belongs. The resource group must be created by the current Alibaba Cloud account in Resource Management. For more information, see Create a resource group.

Step 2: Add an acceleration area

By adding an acceleration area, you can specify the regions of the Global Accelerator users and allocate bandwidth to the regions.

In the Configure Acceleration Area step, select an acceleration area and click Next.

Step 3: Configure a listener

A listener listens for connection requests and distributes the requests to endpoints based on the port and the protocol that you specify. Each listener is associated with an endpoint group. You can associate an endpoint group with a listener by specifying the region to which you want to distribute network traffic. After you associate an endpoint group with a listener, network traffic is distributed to the optimal endpoint in the endpoint group.

In the Configure listeners step, configure the following parameters and click Next.

Step 4: Configure endpoint groups and endpoints

1. In the Configure an endpoint group step, configure the endpoint group and endpoints.

   Parameter	Description
   Region	Select the region in which the endpoint group is deployed. In this example, US (Silicon Valley) is selected.
   Endpoint Configuration	Client requests are routed to endpoints. To add an endpoint, configure the following parameters: Backend Service Type: In this example, Custom IP is selected. Backend Service: Enter the public IP address of the backend service that you want to accelerate. Weight: Enter the weight of the endpoint. Valid values: 0 to 255. GA distributes network traffic to endpoints based on the configured weights. In this example, the default value 255 is used. Warning If you set the weight of an endpoint to 0, Global Accelerator stops distributing network traffic to the endpoint. Proceed with caution.
   Preserve Client IP	By default, client IP address preservation is enabled for HTTPS listeners. This feature allows you to view client IP addresses on backend servers. HTTP listeners can retrieve client IP addresses from the X-Forwarded-For HTTP header. For more information, see Preserve client IP addresses.
   Backend Service Protocol	Select the protocol that is used by backend servers. Default value: HTTP.
   Port Mapping	If the listener port is different from the port over which the endpoint provides services, you must configure this parameter. Listener Port: Enter the listener port. Endpoint Port: Enter the port over which the endpoint provides services. If the listener port and the port that is used by the endpoint to provide services are the same, you do not need to add a port mapping. Global Accelerator automatically forwards client requests to the listener port of the endpoint. In this example, no port mapping is configured.
   Traffic Distribution Ratio	Specify a traffic distribution ratio for the endpoint group. Valid values: 0 to 100. In this example, the default value 100 is used.
   Health Check	Specify whether to enable the health check feature. After you enable this feature, you can use health checks to check the status of endpoints. For more information about the health check feature, see Enable and manage health checks. In this example, the health check feature is disabled.

2. Read Compliance Commitments Regarding Cross-border Data Transfers, select Agree to the Preceding Compliance Agreement, and then click Next.

   In this example, cross-border acceleration is required. Therefore, you must agree to Compliance Commitments Regarding Cross-border Data Transfers.

   After the GA instance is created, the Transmission Network Type is BGP (Multi-ISP) Pro by default. You can accelerate content delivery between regions in the Chinese mainland and regions outside the Chinese mainland, including China (Hong Kong), China (Macao), and China (Taiwan). No additional configuration is required. For more information, see Pay-by-data-transfer.

3. In the Configuration Review step, check the configurations and click Submit.

   Note

   It takes 3 to 5 minutes to create a Global Accelerator instance.

4. (Optional) After you create a GA instance, you can click the instance ID on the Instances page to view the configurations of the instance. On the instance details page, you can click tabs, such as Instance Information, Listeners, and Acceleration Areas, to view more details.

Step 5: Configure a CNAME record

1. Log on to the Alibaba Cloud DNS console.

2. If your domain name is not registered by using Alibaba Cloud Domains, you must add your domain name to Alibaba Cloud DNS.

   Note

   If your domain name is not registered by using Alibaba Cloud Domains, you must add your domain name to Alibaba Cloud DNS before you configure a DNS record. For more information, see the "Add a domain name" section of the Manage domain names topic. If your domain name is registered by using Alibaba Cloud Domains, skip this step.

3. On the Domain Name Resolution page, find the domain name and click DNS Settings in the Actions column.

4. On the DNS Settings page, perform the following steps to modify the existing A record and click OK.

   1. Find the A record and click Modify.

   2. In the Modify DNS Record panel, select Outside mainland China, North America, and United States from the DNS Request Source drop-down list.

5. On the DNS Settings page, click Add DNS Record, configure the parameters in the following table, and then click OK.

   Parameter	Description
   Record Type	Select CNAME from the drop-down list.
   Hostname	Enter the prefix of the domain name that you want to accelerate. If the domain name that you want to accelerate is www.aliyun.com, set the prefix to www. If the domain name that you want to accelerate is aliyun.com, set the prefix to @. If the domain name that you want to accelerate is *.aliyun.com, set the prefix to *. If the domain name that you want to accelerate is mail.aliyun.com, set the prefix to mail. In this example, www is entered.
   DNS Request Source	Select Default from the drop-down list.
   Record Value	Enter the CNAME assigned by Global Accelerator. You can find the CNAME assigned by Global Accelerator on the Instances page.
   TTL	Specify the period of time for which a record is cached by a DNS server. A smaller TTL value specifies that the resolver retains the information in the cache for a shorter period of time. In this example, the default value 10 Minutes is used.

Step 6: Test the acceleration performance

In this example, the Alibaba Cloud Linux 3 operating system is used. The command that is used to run the test varies based on the operating system. For more information, refer to the user guide of the operating system.

1. Open the CLI on a client in the acceleration region. In this example, a client in the China (Shenzhen) region is used.

2. Run the following command to check whether the CNAME record takes effect:

   ping <accelerated domain name>

   If the CNAME in the output is the same as the CNAME allocated by Global Accelerator, the CNAME record takes effect.

3. Run the following command to test the network latency:

   curl -o /dev/null -s -w "time_connect: %{time_connect}\ntime_starttransfer: %{time_starttransfer}\ntime_total: %{time_total}\n" "http[s]://<Accelerated domain name>"

   Take note of the following parameters:

   • time_connect: The period of time that is required to establish a TCP connection. Unit: seconds.

   • time_starttransfer: The start time of data transfer. The start time refers to the amount of time from when the client sends a request to the backend server to when the first byte is sent to the client. Unit: seconds.

   • time_total: The total connection time. The total connection time refers to the period of time from the time when the client sends a request to the time when the client receives the last byte from the backend server. Unit: seconds.

   The test result shows that the total connection time is reduced. This indicates that Global Accelerator has reduced the network latency when users from the China (Shenzhen) region access the web services deployed in the US (Silicon Valley) region.

   Figure 1. Network latency before acceleration

   Figure 2. Network latency after acceleration

   Note

   The acceleration performance of Global Accelerator varies based on the actual workloads.