CDN:Acelerar a obtenção de recursos de uma instância ECS com CDN

Prerequisites

Before you begin, ensure that you have:

• An registered an Alibaba Cloud account . You have completed account verification if you want to use services covering the Chinese mainland.

• Activate Alibaba Cloud CDN enabled.

• An ECS instance available for content hosting. For more information, see Create an instance.

• Domain name(s) for acceleration.

Add a domain name

1. Log on to the Alibaba Cloud CDN console.

2. In the left-side navigation pane, click Domain Names, click Add Domain Name, and configure the following parameters as the Example:

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   • The first time you add a domain name in the CDN console, you must verify the ownership of the domain name (only the ownership of the Configure a CNAME record needs to be verified). If you have already verified your domain ownership, skip this step. For more information, see Verify domain name ownership.

   • For more information about the parameters and precautions, see Step 1: Configure business information.

   • Domain Name to Accelerate: image.example.com

   • Business Type: Image and Small File

   • Region: Global

   

3. Click Add Origin Server to configure the origin server.

   For Origin Info, select Origin Domain or IP, and enter the origin domain name or the public IP address of the ECS instance. In this example, the origin information is the origin domain name ecs.example.com. Keep the default values for other parameters.

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   For more information about the parameters and precautions, see Step 2: Set up origin servers.

   

4. After you configure the origin server, click Next.

5. Wait for verification.

   After the domain name passes the verification, the status of the domain name changes to Enabled. In this case, the domain name is added to CDN.

   

6. When the Domain Status becomes Enabled, the CNAME of the accelerated domain name is displayed. In this example, the CNAME is image.example.com.w.kunlunsl.com.

Set up the domain name

Enable the corresponding features based on your business requirements to improve acceleration performance and secure data transmission.

1. In the CDN console, go to Domain Names. In the domain name list, click Manage in the Actions column of the target domain name.

2. Based on your business requirements, configure the features described in the following list:

   • Increase the cache hit ratio

     Configure CDN cache expiration for cached resources based on the following rules to increase the cache hit ratio:

     • Specify a TTL of one month or longer for static files that are infrequently updated, such as images and application packages.

     • Specify a TTL based on your business requirements for static files that are frequently updated, such as JavaScript and CSS files.

     • Specify a TTL of 0 seconds to disable caching for dynamic files, such as PHP, JSP, and ASP files.

   • Specify the site to which POPs redirect requests

     If multiple sites are hosted on your origin server, and the site on which the requested content resides is different from the site to which the accelerated domain name points, you need to Configure default origin host. The origin host specifies the site to which Alibaba Cloud CDN redirects requests.

   • Improve the efficiency of file downloads from POPs

     After you enable the Configure range origin fetch feature, the ECS instance that functions as the origin server returns the file chunk that is specified by the Range header to POPs. This reduces origin traffic and accelerates content delivery.

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     The range origin fetch feature is suitable for large file distribution such as audio and video streaming. You do not need to enable the range origin fetch feature when you use Alibaba Cloud CDN to accelerate the delivery of images.

   • Increase the cache hit ratio or file distribution efficiency

     After you enable the Ignore Parameters feature, CDN POPs remove the parameters after ? in the URL when generating a cache hashkey. This allows the client to hit the same cache file when accessing the same resource file with different parameters, which helps increase the cache hit ratio and reduce traffic to origin.

   • Limit users who can access resources on POPs and prevent other websites from referencing your resource links

     After you configure a Configure a Referer blacklist or whitelist, CDN allows or blocks requests based on user identities. If a request is allowed, CDN returns the URL of the requested resource. If a request is denied, CDN returns the HTTP 403 status code.

   • Protect websites from hotlinking issues and IP theft

     Configure URL signing cannot be performed without an origin server. The origin server generates signed URLs based on the URL signing settings on the POPs. After you enable URL signing, only requests that pass authentication can access resources on POPs.

Configure CNAME

To enable CDN acceleration, add a CNAME record with your DNS provider to map your domain name to the CNAME. Without this, requests cannot be redirected to POPs.

1. Use the Alibaba Cloud account to which the accelerated domain name belongs to log on to the Authoritative DNS Resolution page in the Alibaba Cloud DNS console.

2. On the Public Zone page, find the root domain name (example.com) of the accelerated domain name and click DNS Settings in the Actions column.

3. Click Add Record to add a CNAME record.

   • Type: CNAME

   • Hostname: image

   • Value: Enter the CNAME value that you obtained from the domain name list, which is image.example.com.w.kunlunsl.com in this example.

   • Keep the default values for other parameters.

4. Verify that the CNAME record takes effect.

   • Method 1: Check the status in the DCDN console

     1. Go to the Domain Names page in the Alibaba Cloud DCDN console.

     2. Find the target domain name. Hover the pointer over the CNAME status. If the status is Configured, the CNAME record has taken effect.

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        A new CNAME record added in Alibaba Cloud DNS takes effect immediately. A modified CNAME record takes effect after its TTL expires. The default TTL is 10 minutes. During this period, the status may still be displayed as To Be Configured in the console. You can ignore this status.

   • Method 2: Verify using the nslookup command

     1. Open Command Prompt in Windows or Terminal in macOS or Linux.

     2. Run the nslookup -type=CNAME accelerated domain name command. If the output matches the CNAME provided in the console for the accelerated domain name, the acceleration service is active. For example:

        nslookup -type=CNAME www.example.com