Cache stores resolution results in memory to accelerate resolution of repeated queries for the same domain name in your private network.
Add Domain Name
Cache retention keeps the resolution record of a domain name in memory and never releases it. If no cached record exists, the system fetches one. If a cached record already exists, the system does not trigger an update. After the TTL of the record expires, the next query for the domain name is answered with the existing cached record, and the system then updates the record. If the query returns no record, the system keeps answering with the previous record.
Enable cache retention for frequently accessed or business-critical domain names. The resolution results are kept in the cache permanently, which speeds up resolution in your private network and mitigates the service interruption caused by a failure of the authoritative DNS provider of the domain name. During such a failure, the system keeps answering queries with the previously resolved records.
For a domain name that has a CNAME record, cache retention applies only to the first hop of the CNAME. The domain names after that hop are not cached. To accelerate the entire resolution path, add every domain name in the CNAME chain as a cache retention domain name.
Go to the Alibaba Cloud DNS - Private Zone page.
Click Cache > Add Domain Name.
Configure the parameters.
Parameter
Description
Domain Name
Enter the domain name for which you want to enable cache retention. Cache retention applies only to the exact domain name that you enter and does not include its subdomains.
Record Type
The DNS record type to cache. Supported types:
A, AAAA, CNAME, TXT, MX, SRV, and PTR.
Cache Retention
The resolution results of the domain name are kept in the cache module and are never released. Queries are answered from the cached data, which delivers resolution in under 1 ms.
After the TTL of the cached data expires, a new query for the domain name is answered from the cached data first, and the system updates the cached data from the origin at the same time.
Effective Scope
Defines the network environments in which cache retention takes effect. Networks outside this scope cannot obtain the resolution acceleration that cache retention provides.
In the Effective Scope section, use the multi-level cascading selector to select an Account (the current account or a linked account), VPC Type (Standard VPC or EDS Workspace VPC), region, and the specific VPC instance in sequence. After you select the target VPC-connected instances, the selected items appear below the selector. For cross-account management, click + Cross-Account VPC Private Zone Management. VPC data is synchronized with a delay. If your VPC data has not been synchronized, try again in 30 minutes.
The system resolves the subdomains of a domain name that has cache retention enabled at a fixed interval, obtains the latest resolution records, and updates them in the DNS cache. This accelerates resolution of these domain names in the private networks within the effective scope of the cache rule.
A cache retention rule for domain name resolution takes effect only in the network environments within the effective scope. If you access the domain name from a network outside that scope, you cannot obtain the resolution acceleration that cache retention provides.
This feature applies only to external public domain names that are queried through the "Recursion" module. Domain names queried through the "Private Zone (standard zone)" module or the "Forwarding" module are not supported yet.
For detailed billing rules, see 2. Cache management.
Modify Domain Name
Go to the Alibaba Cloud DNS - Private Zone page.
Click Cache, find the domain name, and then click Edit in the Actions column.
Delete Domain Name
Go to the Alibaba Cloud DNS - Private Zone page.
Click Cache, find the domain name, and then click Delete in the Actions column.
Clear Cache
During an urgent change, a workload in your private network may require the private zone service to serve the latest resolution records of a domain name. If the domain name is already configured as a cache retention domain name, use cache clearing to remove its cached data from the cache servers within the effective scope of the cache rule. Cache clearing is billed per operation on a pay-as-you-go basis.
Go to the Alibaba Cloud DNS - Private Zone page.
Click Cache, find the domain name, and then click Clear Cache in the Actions column.
In the dialog box that appears, confirm the operation.
NoteCache clearing refreshes only the domain name that you select and does not include its subdomains. The rate limit for cache clearing is two operations per second.