ACK Serverless cluster supports the managed CoreDNS component. This topic describes the performance metrics of managed CoreDNS.
QPS performance reference
The performance of managed CoreDNS is affected by factors such as the number of Services and pods in the cluster, cache size, and cache TTL. The following information is for reference only. managed CoreDNS deploys two pods by default and automatically scales based on loads.
The following information applies only to scenarios where the number of Services and pods in the cluster does not exceed 50,000. If your cluster contains more than 50,000 Services and pods, contact us by submitting a ticket.
Resolve in-cluster domain names
When resolving in-cluster domain names, a single pod can provide a performance of 5,000 queries per second. The default two pods can provide a performance of 10,000 queries per second.
Resolve external domain names
When resolving external domain names, CoreDNS is limited by the performance of external DNS services.
VPC domain names (hosted by PrivateZone)
The default upstream DNS service for CoreDNS is PrivateZone (internal DNS resolution) service, with the corresponding addresses: 100.100.2.136 and 100.100.2.138. For internal domain names, the default two pods of managed CoreDNS can provide a performance of 8,000 queries per second.
We recommend that you add caching for frequently accessed domain names to improve the resolution efficiency of these domain names in PrivateZone.
The limits of PrivateZone also affect the performance upper limit of CoreDNS, including the following:
The DNS resolution request threshold for each IP address in a VPC is 5,000 queries per second. Requests exceeding this threshold may be throttled.
The external recursive resolution request threshold for each IP in a VPC is 600 queries per second. Requests exceeding this threshold may be throttled.
All ECS instances in a VPC can send up to 5,000 recursive DNS requests to the Internet per second. If the upper limit is exceeded, throttling may be triggered.
Public domain names
The resolution performance of public domain names is affected by the public DNS service you use and also depends on the PrivateZone limits.
We recommend that you add caching for frequently accessed or important domain names to improve the resolution efficiency of public domain names in PrivateZone. This also ensures that cached results continue to be returned during authoritative DNS provider service failures.
References
You can improve DNS performance by using the DNS cache component. For more information, see Manage the BlazingDNS component.