Weighted internal DNS resolution lets you configure multiple IP addresses or domain names for the same host record and DNS query source. When a DNS server responds to a query, it returns different DNS records based on their preset weights. This feature distributes traffic across multiple servers to achieve load balancing.
Prerequisites
Weighted resolution is supported only for domain names in Internal authoritative accelerated zones. This feature is not supported for domain names in Internal authoritative standard zones.
The domain name must have multiple A, AAAA, or CNAME records that share the same host record and DNS query source.
Limits
Category | Supported | Not supported |
Internal authoritative domain name | Accelerated zone | Standard zone |
Record type | A, AAAA, and CNAME records. | Other record types. |
DNS record limit | 100 | Not applicable. |
Weight value rules | The weight can be an integer from 0 to 100. The default weight ratio is 1:1. If a record's weight is set to 0, the Internal authoritative DNS server does not return its value. If all records have a weight of 0, the server returns all record values. | Not applicable. |
DNS query source | Default, Alibaba Cloud, and custom lines. Note The weights for different query source lines are independent of each other. | DNS records from different query sources. |
For records with the same host record and DNS query source:
If a record's value contains multiple domain names, only the weight pattern is available.
If a record value contains multiple IPv4 addresses, you can configure a weight-based load balancing policy.
If the record values are multiple IPv4 or IPv6 addresses, you can enable the weighted load balancing policy.
Procedure
This example shows how to set weights for multiple A records.
Click the Internal Authoritative tab, and then click Custom Domain Names.
On the Custom Domain Names tab, find the domain name that you want to manage and click Configure in the Actions column.
On the DNS Records page, click Add Record. In the dialog box that opens, select Form Mode or Visual Mode. This topic uses Form Mode as an example.
In the Add Record dialog box, set Record Value Load Balancing Policy to Weight and configure parameters such as record type, host record, DNS query source, and TTL. In the Record Collection section, add multiple record values and set a weight for each. Then, click OK.
If you select the polling load balancing policy, the system returns all DNS records by default. However, if there are multiple CNAME records, only one record is returned at a time.