Overview

Application Scenarios

DNS is a critical foundational service in Kubernetes. When DNS policies are misconfigured, especially in large-scale clusters, DNS resolution may time out or fail. In severe cases, a large number of services in the cluster may fail to be resolved. This section describes the best practices for optimizing CoreDNS in Kubernetes clusters to help prevent these issues.

Solution

CoreDNS optimization covers both client-side and server-side improvements.

On the client side, you can optimize domain name resolution requests to reduce latency, use appropriate container images, and use NodeLocal DNSCache to reduce resolution failures.

• Optimizing Domain Name Resolution Requests
• Selecting a Proper Image
• Avoiding Occasional DNS Resolution Timeout Caused by IPVS Defects
• Using NodeLocal DNSCache
• Keeping CoreDNS Up to Date
• Adjusting the DNS Settings of the VPC and VM

On the server side, you can adjust the CoreDNS deployment or fine-tune its settings to improve availability and throughput.

• Monitoring CoreDNS
• Adjusting the CoreDNS Deployment Status

• Properly Configuring CoreDNS

For details about CoreDNS settings, see https://coredns.io/.

CoreDNS open-source community: https://github.com/coredns/coredns

Prerequisites

• A CCE cluster is available. For details about how to create a cluster, see Buying a CCE Standard/Turbo Cluster.
• You can access the cluster using kubectl. For details, see Accessing a Cluster Using kubectl.
• The CoreDNS add-on is installed in the cluster. The latest version of CoreDNS is recommended. For details, see CoreDNS.