Configure an origin server

Precautions

• When DCDN retrieves resources from an origin server, the origin server is billed for data transfer. For example, if the origin server is a data center, the data center is billed for data transfer and bandwidth resources. If the origin server is an OSS bucket, you are charged for traffic and bandwidth consumed by the origin server.
• DCDN supports switchover between primary and secondary origin servers. If multiple origin servers are configured, DCDN preferentially redirects requests to the origin server whose Priority is Primary. If the primary origin server fails three consecutive health checks, DCDN redirects requests to the origin server whose Priority is Secondary. If the primary origin server passes the health check, the system marks the origin server as available again and restores the priority of the origin server to primary. If you set the same priority for all origin servers, DCDN automatically redirects requests to the origin servers based on round-robin scheduling.
  Note DCDN performs Layer 4 health checks on origin servers. Port 80, port 443, and the custom port that you have specified are all probed. Probes are sent every 2.5 seconds. If an origin server fails three consecutive probes, the system marks the origin server as unavailable.

Add an origin server or modify the information about an origin server

1. Log on to the DCDN console.
2. In the left-side navigation pane, click Domain Names.
3. On the Configure page, find the domain name that you want to manage and click Domain Names in the Actions column.
4. On the Basic Settings tab, find the Origin Information section.
5. In the Origin Information section, click Modify.
6. In the Add Origin Server dialog box, configure the parameters that are described in the following table.
   

   Parameter	Description
   Type	Select the type of the origin server and enter the address of the origin server. OSS Domain If you use an Object Storage Service (OSS) bucket as the origin server, you can enter the public domain name of the OSS bucket, for example, ***.oss-cn-hangzhou.aliyundoc.com. Internal domain names of OSS buckets are not supported. You can view the public domain name of an OSS bucket in the OSS console. You can also select an OSS bucket that belongs to the current Alibaba Cloud account from the Domain Name drop-down list. IP You can enter public IP addresses of one or more servers. Public IP addresses of Alibaba Cloud Elastic Compute Service (ECS) instances do not need to be reviewed. Private IP addresses are not supported. Site Domain You can enter the domain name of an origin server. To configure multiple domain names, repeat the preceding steps. Note The origin domain name must be different from the accelerated domain name. If the origin domain name is the same as the accelerated domain name, a DNS resolution loop occurs, and requests cannot be redirected to the origin server. The domain name must be in lowercase letters. If a domain name contains Chinese characters, such as 阿里云.网址, you must apply for an ICP number for the domain name and use the Punnycode tool to convert the Chinese domain name to an English domain name, such as xn--fiq****.xn--eq****.
   Priority	You can configure priorities to specify primary and secondary origin servers. The primary origin server has a higher priority than the secondary origin server. DCDN preferentially redirects requests to the primary origin server. For example, if you specify Origin Server A as the primary origin server and specify Origin Server B as the secondary origin server, user requests are preferentially redirected to Origin Server A. If Origin Server A is down, user requests are redirected to Origin Server B until Origin Server A works as expected again.
   Weight	If origin servers have the same priority, DCDN redirects requests to the origin servers based on the weights of the origin servers. This way, loads are balanced among the origin servers. You can specify a weight based on your business requirements. The weight of an origin server ranges from 0 to 100. An origin server that has a higher weight receives more requests. The default value is 10. For example, you specify Origin Server A and Origin Server B as primary origin servers. If the weight of Origin Server A is 80 and the weight of Origin Server B is 20, DCDN redirects 80% of requests to Origin Server A and 20% of requests to Origin Server B.
   Port	Select a port based on the protocol that is supported by the origin server. Port 80: Requests are redirected to the origin server over port 80. Port 443: Requests are redirected to the origin server over port 443. Make sure that the origin server supports HTTPS. Note Before you can specify a custom port, you must set Static Origin Protocol Policy and Dynamic Origin Protocol Policy to HTTP after you add a domain name. For more information, see Configure the static origin protocol policy and Configure back-to-origin requests to retrieve dynamic content.

7. Click OK.