CoreDNS

Add-on Overview

CoreDNS is a DNS server that uses chain plug-ins to provide domain name resolution services for Kubernetes clusters. It is the recommended DNS server solution by the Kubernetes community.

Add-on Parameters

**Table 1** Parameters
Parameter	Mandatory	Type	Description
basic	No	object	Basic configuration parameters, which do not need to be specified
flavor	Yes	Table 2 object	Flavor parameters
custom	Yes	Table 3 object	Custom parameters

**Table 2** Configuration of flavor
Parameter	Mandatory	Type	Description
replicas	Yes	int	Number of pods. The default value is 2.
resources	Yes	Array of resources object	Container resource (CPU and memory) quotas

**Table 3** Configuration of custom
Parameter	Mandatory	Type	Description
servers	No	object	Configuration of servers
stub_domains	No	Map<String>[]string	Stub domain configuration
multiAZEnable	No	bool	Whether to enable the forcible mode of multi-AZ deployment for the deployment component. The default value is false. Deployment pods of the add-on will be forcibly scheduled to nodes in different AZs. If there are fewer AZs than pods, the extra pods will fail to run. If both multiAZEnable and multiAZBalance are set to true, the settings of multiAZBalance take effect, which means, the equivalent mode of multi-AZ deployment is used.
multiAZBalance	No	bool	Whether to enable the equivalent mode of multi-AZ deployment for the deployment component. The default value is false. Deployment pods of the add-on are evenly scheduled to the nodes in the cluster in each AZ. If a new AZ is added, it is recommended that you increase add-on pods for cross-AZ HA deployment. With the equivalent multi-AZ deployment, the difference between the number of add-on pods in different AZs will be less than or equal to 1. If resources in one of the AZs are insufficient, pods cannot be scheduled to that AZ.
tolerations	No	Array of Table 5	Toleration configuration

**Table 4** Data structure of the resources field
Parameter	Mandatory	Type	Description
limitsCpu	Yes	String	CPU size limit (unit: m)
limitsMem	Yes	String	Memory size limit (unit: Mi)
name	Yes	String	Add-on name. The value is fixed at coredns.
requestsCpu	Yes	String	Requested CPU size (unit: m)
requestsMem	Yes	String	Requested memory size (unit: Mi)

**Table 5** Taints and tolerations
Parameter	Mandatory	Type	Description
key	No	String	Taint key
effect	No	String	Taint policy
operator	No	String	Operator
tolerationSeconds	No	Int	Toleration time window

**Table 6** Configuration of server
Parameter	Mandatory	Type	Description
port	No	Int	Domain port number. The default value is 5353.
zones	No	Array of Table 8	Domain configuration
plugins	No	Array of Table 7	Configuration of plugin

**Table 7** Configuration of plugin
Parameter	Mandatory	Type	Description
name	Yes	String	Plugin name
configBlock	No	String	Configuration of plugin
parameters	No	String/Int	Extended parameters of the plugin

**Table 8** Configuration of zone
Parameter	Mandatory	Type	Description
zone	Yes	String	Domain value. The default value is ".".

Example Request

{
	"kind": "Addon",
	"apiVersion": "v3",
	"metadata": {
		"annotations": {
			"addon.install/type": "install"
		}
	},
	"spec": {
		"clusterID": "2292498e-******-0255ac1001ba",
		"version": "1.29.2",
		"addonTemplateName": "coredns",
		"values": {
                        "basic": {
				"basickey":"val"
			},
			"flavor": {
				"replicas": 2,
				"resources": [{
					"limitsCpu": "2000m",
					"limitsMem": "2000Mi",
					"name": "coredns",
					"requestsCpu": "2000m",
					"requestsMem": "2000Mi"
				}]
			},
			"custom": {
				"multiAZBalance": false,
				"multiAZEnabled": false,
				"node_match_expressions": [],
				"servers": [{
					"plugins": [{
						"name": "bind",
						"parameters": "{$POD_IP}"
					},
					{
						"configBlock": "servfail 5s",
						"name": "cache",
						"parameters": 30
					},
					{
						"name": "errors"
					},
					{
						"name": "health",
						"parameters": "{$POD_IP}:8080"
					},
					{
						"name": "ready",
						"parameters": "{$POD_IP}:8081"
					},
					{
						"configBlock": "pods insecure\nfallthrough in-addr.arpa ip6.arpa",
						"name": "kubernetes",
						"parameters": "cluster.local in-addr.arpa ip6.arpa"
					},
					{
						"name": "loadbalance",
						"parameters": "round_robin"
					},
					{
						"name": "prometheus",
						"parameters": "{$POD_IP}:9153"
					},
					{
						"configBlock": "policy random",
						"name": "forward",
						"parameters": ". /etc/resolv.conf"
					},
					{
						"name": "reload"
					}],
					"port": 5353,
					"zones": [{
						"zone": "."
					}]
				}],
				"stub_domains": {
					
				},
				"tolerations": [{
					"key": "node.kubernetes.io/not-ready",
					"operator": "Exists",
					"effect": "NoExecute",
					"tolerationSeconds": 60
				},
				{
					"key": "node.kubernetes.io/unreachable",
					"operator": "Exists",
					"effect": "NoExecute",
					"tolerationSeconds": 60
				}]
			}
		}
	}
}

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