Enable auto-scaling for CoreDNS pods#1351
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This is successfully applied in staging. I have not yet applied it to production as terraform wants to upgrade the eks managed node group version (even though i'm not targeting that resource), which would be disruptive to the cluster. |
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I followed the link to the docs mentioned in this change (and locally ran the suggested command) and I didn't see any mention of an |
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It appears that field was added in a newer version of the configuration. Using the command they mention to pull the configuration we're using (based on our addon version), returns a config that contains that field. {
"$ref": "#/definitions/Coredns",
"$schema": "http://json-schema.org/draft-06/schema#",
"definitions": {
"Coredns": {
"additionalProperties": false,
"properties": {
"affinity": {
"default": {
"affinity": {
"nodeAffinity": {
"requiredDuringSchedulingIgnoredDuringExecution": {
"nodeSelectorTerms": [
{
"matchExpressions": [
{
"key": "kubernetes.io/os",
"operator": "In",
"values": [
"linux"
]
},
{
"key": "kubernetes.io/arch",
"operator": "In",
"values": [
"amd64",
"arm64"
]
}
]
}
]
}
},
"podAntiAffinity": {
"preferredDuringSchedulingIgnoredDuringExecution": [
{
"podAffinityTerm": {
"labelSelector": {
"matchExpressions": [
{
"key": "k8s-app",
"operator": "In",
"values": [
"kube-dns"
]
}
]
},
"topologyKey": "kubernetes.io/hostname"
},
"weight": 100
}
]
}
}
},
"description": "Affinity of the coredns pods",
"type": [
"object",
"null"
]
},
"annotationTopologyMode": {
"description": "Topology mode for annotations",
"enum": [
"Disabled",
"Auto"
],
"type": "string"
},
"autoScaling": {
"additionalProperties": false,
"description": "autoScaling configurations",
"properties": {
"enabled": {
"default": false,
"description": "the option to enable eks managed autoscaling for coredns",
"type": "boolean"
},
"maxReplicas": {
"description": "the max value that autoscaler can scale up the coredns replicas to",
"maximum": 1000,
"minimum": 2,
"type": "integer"
},
"minReplicas": {
"default": 2,
"description": "the min value that autoscaler can scale down the coredns replicas to",
"maximum": 1000,
"minimum": 2,
"type": "integer"
}
},
"required": [
"enabled"
],
"type": "object"
},
"computeType": {
"type": "string"
},
"corefile": {
"description": "Entire corefile contents to use with installation",
"type": "string"
},
"nodeSelector": {
"additionalProperties": {
"type": "string"
},
"type": "object"
},
"podAnnotations": {
"properties": {},
"title": "The podAnnotations Schema",
"type": "object"
},
"podDisruptionBudget": {
"description": "podDisruptionBudget configurations",
"properties": {
"enabled": {
"default": true,
"description": "the option to enable managed PDB",
"type": "boolean"
},
"maxUnavailable": {
"anyOf": [
{
"pattern": ".*%$",
"type": "string"
},
{
"type": "integer"
}
],
"default": 1,
"description": "maxUnavailable value for managed PDB, can be either string or integer; if it's string, should end with %"
},
"minAvailable": {
"anyOf": [
{
"pattern": ".*%$",
"type": "string"
},
{
"type": "integer"
}
],
"description": "minAvailable value for managed PDB, can be either string or integer; if it's string, should end with %"
}
},
"type": "object"
},
"podLabels": {
"properties": {},
"title": "The podLabels Schema",
"type": "object"
},
"replicaCount": {
"type": "integer"
},
"resources": {
"$ref": "#/definitions/Resources"
},
"tolerations": {
"default": [
{
"key": "CriticalAddonsOnly",
"operator": "Exists"
},
{
"effect": "NoSchedule",
"key": "node-role.kubernetes.io/control-plane"
}
],
"description": "Tolerations of the coredns pod",
"items": {
"type": "object"
},
"type": "array"
},
"topologySpreadConstraints": {
"description": "The coredns pod topology spread constraints",
"type": "array"
}
},
"title": "Coredns",
"type": "object"
},
"Limits": {
"additionalProperties": false,
"properties": {
"cpu": {
"type": "string"
},
"memory": {
"type": "string"
}
},
"title": "Limits",
"type": "object"
},
"Resources": {
"additionalProperties": false,
"properties": {
"limits": {
"$ref": "#/definitions/Limits"
},
"requests": {
"$ref": "#/definitions/Limits"
}
},
"title": "Resources",
"type": "object"
}
}
} |
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I've just applied this successfully in prod. |
zackgalbreath
approved these changes
May 1, 2026
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The goal of this is to reduce flakiness in host name resolution by ensuring that CoreDNS isn't overloaded.