Excessive DNS query pressure can cause CoreDNS failures, leading to a cluster-wide meltdown. Thus, per-pod or per-node DNS proxy is a common high-availability solution. By binding the clusterIP of the kube-dns service to the local node, node-local DNS can provide seamless DNS interception and proxying, meeting the demands of low latency and high throughput. However, proxy's breakdown can directly lead to access failures, lacking high availability.
To solve this issue, we use cgroup eBPF to implement enhanced service redirection for node-local DNS, inspired by Cilium's LocalRedirectPolicy. Based on the health status of the local proxy or the redirection QoS strategy, the query of the kube-dns service can be dynamically resolved to the local node-local DNS, otherwise normally forwarded to CoreDNS. This scheme is independent of the CNI, and could cooperate with kube-proxy, offer multiple service redirection strategies and provide production-grade quality assurance for node-local DNS.