CoreDNS - Container Service for Kubernetes - Alibaba Cloud Documentation Center

CoreDNS is the default plug-in used to implement Domain Name System (DNS)-based service discovery in Container Service for Kubernetes (ACK) clusters and ACK Edge clusters. You can also use CoreDNS to implement service discovery in ACK Serverless clusters. The topic introduces CoreDNS and describes the usage notes and release notes for CoreDNS.

Introduction

CoreDNS provides DNS resolution capabilities within Kubernetes clusters. ACK maintains a mapping between CoreDNS versions and Kubernetes versions. When you create or update a Kubernetes cluster, the CoreDNS version that is installed or updated depends on the Kubernetes version of the cluster. For more information about the mapping, see CoreDNS version in Kubernetes.

The CoreDNS installation policy varies with cluster types.

The system automatically installs the CoreDNS plug-in in the clusters when ACK clusters or ACK Edge clusters are created. CoreDNS complies with the Kubernetes DNS-Based Service Discovery specification. For more information, see Kubernetes DNS-Based Service Discovery.
You can select the CoreDNS plug-in or not when you create ACK Serverless clusters. For more information, see DNS-based Service discovery components supported by ACK Serverless clusters.

Usage notes

For more information about the features of CoreDNS and how to use CoreDNS, see Configure DNS resolution.

Important

Before you update CoreDNS, take note of the following items:

Read and understand the CoreDNS update considerations. For more information, see Configure ACK to automatically update CoreDNS.
Back up the CoreDNS ConfigMap in the kube-system namespace.

Release notes

October 2024

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.11.3.2-f57ea7ed6-aliyun	ACK managed clusters and ACK dedicated clusters that run Kubernetes 1.21 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.11.3.2-f57ea7ed6-aliyun	2024-10-21	The Firewall plug-in is supported in CoreDNS, and the Forward plug-in can proceed to the next plug-in based on the returned status code. Custom topology constraints for CoreDNS can be configured on the Operations > Add-ons page in the console.	No impact on workloads.

May 2023

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.9.3.16-4341f22f-aliyun	ACK Serverless clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.9.3.16-4341f22f-aliyun	2023-05-09	The default memory request of CoreDNS pods is increased to 4 GiB. This helps avoid scheduling the CoreDNS pods to a shared instance. You can modify the memory request in the CoreDNS ConfigMap.	If you update CoreDNS to this version, ACK may attempt to schedule the CoreDNS pods to an elastic container instance with higher specifications.

April 2023

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.9.3.10-7dfca203-aliyun	ACK managed clusters and ACK dedicated clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.9.3.10-7dfca203-aliyun	2023-04-03	Pods can be scheduled based on zone anti-affinity. The possibility of pod eviction in scenarios where auto scaling of nodes is enabled is reduced.	If all schedulable nodes in a cluster belong to a single zone, CoreDNS pods may fail to be scheduled or CoreDNS may fail to be updated. To ensure the high availability of Domain Name System (DNS) services, we recommend that you add new nodes in different zones to the cluster. This way, CoreDNS pods can be scheduled to nodes that are distributed across multiple zones.

August 2022

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.9.3.6-32932850-aliyun	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.9.3.6-32932850-aliyun	2022-08-25	Kubernetes events can be delivered. For ACK Serverless clusters, the default requested number of vCPUs in CoreDNS is changed to 2.	No impact on workloads.

August 2022

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.9.3.2-8850b5e7-aliyun	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.9.3.2-8850b5e7-aliyun	2022-08-03	The CoreDNS log collection feature can be enabled for Log Center.	No impact on workloads.

July 2022

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.9.3.1-5e7ba42d-aliyun	ACK managed clusters and ACK dedicated clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.9.3.1-5e7ba42d-aliyun	2022-07-11	Some features and issues are fixed. For more information, see CoreDNS-1.9.3 Release. The multi-cluster Services (MCS) feature of Alibaba Cloud Distributed Cloud Container Platform (ACK One) is supported.	No impact on workloads.

April 2022

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.8.4.5-2ce07fd2-aliyun	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.8.4.5-2ce07fd2-aliyun	2022-04-08	Affinity settings are optimized for the scheduling of CoreDNS. This allows you to deploy CoreDNS in a cluster where all nodes have auto scaling enabled.	No impact on workloads.

February 2022

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.8.4.3-644f4735-aliyun	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.8.4.3-644f4735-aliyun	2022-02-22	Caching for DNS resolution results of the ServError type is disabled. Pod anti-affinity settings based on hostnames are changed from preferred to required. The system is forced to schedule pods based on the anti-affinity settings.	The system is forced to schedule pods based on the anti-affinity settings. If the number of CoreDNS pods is greater than that of nodes, some CoreDNS pods change to the Pending state. You must scale out cluster nodes or scale in CoreDNS pods before you update to this image version.

January 2022

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.8.4.2-7d597cff-aliyun	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.8.4.2-3a376cc-aliyun	2022-01-10	Custom parameters are supported. By default, log parsing is enabled.	No impact on workloads.

October 2021

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.8.4.1-3a376cc-aliyun	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters that run Kubernetes 1.20.4 or later	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.8.4.1-3a376cc-aliyun	2021-10-26	EndpointSlice objects can be monitored. IPv6 addresses are supported by DNS resolution.	No impact on workloads.

July 2021

Version	Applicable cluster	Image address	Release date	Description	Impact
v1.7.0.0-f59c03d-aliyun	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters	registry.{{.Region}}.aliyuncs.com/acs/coredns:v1.7.0.0-f59c03d-aliyun	2021-07-08	The default duration of graceful shutdown for CoreDNS and the memory limit of containers in the CoreDNS Deployment are modified. The names of metrics are updated. If your monitoring system is reliant on CoreDNS metrics, you must update the metric names. For more information, see Metric changes. The issue that only the first upstream DNS server specified in the forward plug-in is used is fixed. The deprecated upstream plug-in is no longer compatible. If the upstream plug-in is specified in the Corefile configurations, the upstream plug-in will be automatically deleted in a secure way when CoreDNS is updated.	If you modify the DNS configuration file /etc/resolv.conf on your Elastic Compute Service (ECS) instance, CoreDNS pods are updated or recreated based on the modified /etc/resolv.conf file. You must make sure that the DNS servers specified in this file work as normal before you update CoreDNS.

April 2021

Version	Applicable cluster	Image address	Release date	Description	Impact
1.6.7.edge	ACK Edge clusters	registry.{{.Region}}.aliyuncs.com/acs/coredns:1.6.7.edge	2021-04-23	This version is optimized based on open source CoreDNS 1.6.7. For more information, see CoreDNS-1.6.7 release.	No impact on workloads.

March 2021

Version	Applicable cluster	Image address	Release date	Description	Impact
1.7.0	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters	registry.{{.Region}}.aliyuncs.com/acs/coredns:1.7.0	2021-03-18	The deprecated upstream plug-in is no longer compatible. If the upstream plug-in is specified in the Corefile configurations, the upstream plug-in will be automatically deleted in a secure way when CoreDNS is updated. The names of metrics are updated. If your monitoring system is reliant on CoreDNS metrics, you must update the metric names. For more information, see Metric changes. The issue that only the first upstream DNS server specified in the forward plug-in is used is fixed.	If you modify the DNS configuration file /etc/resolv.conf on your ECS instance, CoreDNS pods are updated or recreated based on the modified /etc/resolv.conf file. You must make sure that the DNS servers specified in this file work as normal before you update CoreDNS.

November 2018

Version	Applicable cluster	Image address	Release date	Description	Impact
1.6.7	ACK managed clusters, ACK dedicated clusters, and ACK Serverless clusters	registry.{{.Region}}.aliyuncs.com/acs/coredns:1.6.7	2018-11-28	This version is optimized based on open source CoreDNS 1.6.7. For more information, see CoreDNS-1.6.7 release.	No impact on workloads.