node-local-dns

node-local-dns

A chart to install node-local-dns.

NodeLocal DNSCache improves Cluster DNS performance by running a DNS caching agent on cluster nodes as a DaemonSet.

In today's architecture, Pods in 'ClusterFirst' DNS mode reach out to a kube-dns serviceIP for DNS queries. This is translated to a kube-dns/CoreDNS endpoint via iptables rules added by kube-proxy. With this new architecture, Pods will reach out to the DNS caching agent running on the same node, thereby avoiding iptables DNAT rules and connection tracking. The local caching agent will query kube-dns service for cache misses of cluster hostnames ("cluster.local" suffix by default).

Further documentation is here

This helm chart works for both kube-proxy setups (iptables or ipvs).

How to install this chart

A simple install with default values, latest chart version and generated name:

helm install --generate-name oci://ghcr.io/deliveryhero/helm-charts/node-local-dns

To install a specific version of this chart:

helm install --generate-name oci://ghcr.io/deliveryhero/helm-charts/node-local-dns --version 2.9.2

To install the chart with the release name my-release:

helm install my-release oci://ghcr.io/deliveryhero/helm-charts/node-local-dns

To install with some set values:

helm install my-release oci://ghcr.io/deliveryhero/helm-charts/node-local-dns --set values_key1=value1 --set values_key2=value2

To install with custom values file:

helm install my-release oci://ghcr.io/deliveryhero/helm-charts/node-local-dns -f values.yaml

Values

Key	Type	Default	Description
affinity	object	{}
config.bindIp	bool	false	If false, it will bind 0.0.0.0, otherwise dnsServer and localDns will be used. bottlerocket-os/bottlerocket#3711 (comment)
config.cacheTTL	int	30	Cache TTL in seconds for DNS records. https://coredns.io/plugins/cache/
config.commProtocol	string	"force_tcp"	Set communication protocol. Options are prefer_udp or force_tcp
config.customConfig	string	""	Overrides the generated configuration with specified one.
config.customUpstreamsvc	string	""	Use a custom upstreamsvc for -upstreamsvc
config.dnsDomain	string	"cluster.local"	Internal k8s DNS domain
config.dnsServer	string	"172.20.0.10"	Main coredns service (kube-dns) ip, used on iptables-mode.
config.enableLogging	bool	false	Set boolean to log DNS requests
config.extraServerBlocks	string	""	Add extra server blocks to the generated configuration.
config.healthPort	int	8080	Port used for the health endpoint
config.localDns	string	"169.254.20.25"
config.noIPv6Lookups	bool	false	If true, return NOERROR when attempting to resolve an IPv6 address
config.port.number	int	53	Port used for DNS traffic
config.port.tcp	string	"dns-tcp"	Port name used for TCP DNS traffic
config.port.udp	string	"dns"	Port name used for UDP DNS traffic
config.prefetch	object	{"amount":3,"duration":"30s","enabled":false,"percentage":"20%"}	If enabled, coredns will prefetch popular items when they are about to be expunged from the cache. https://coredns.io/plugins/cache/
config.serveStale	object	{"duration":"1h","enabled":false,"mode":"verify"}	If enabled, coredns will serve stale cache entries while fetching fresh ones in the background. https://coredns.io/plugins/cache/
config.setupInterface	bool	true
config.setupIptables	bool	true
config.skipTeardown	bool	false
config.upstreamForwardConfig	object	{}	Allows for configuration of upstream server forwarding for the default server block
config.upstreamServers	string	"__PILLAR__UPSTREAM__SERVERS__"	Overrides the upstream servers used for default server block
config.upstreamServiceSelector	object	{"k8s-app":"kube-dns"}	Use a custom upstream service selector
configMapAnnotations	object	{}
configMapLabels	object	{}
daemonsetAnnotations	object	{}
daemonsetLabels	object	{}
dashboard	object	{"annotations":{},"enabled":false,"label":"grafana_dashboard","namespace":"kube-system"}	https://github.com/grafana/helm-charts/blob/main/charts/grafana/README.md
dashboard.label	string	"grafana_dashboard"	label that grafana sidecar is configured to look for
dashboard.namespace	string	"kube-system"	namespace where grafana sidecar is configured to look for dashboards. e.g. "monitoring"
fullnameOverride	string	""
image.repository	string	"registry.k8s.io/dns/k8s-dns-node-cache"
image.tag	string	""	Overrides the image tag whose default is the chart appVersion.
imagePullSecrets	list	[]
initContainers	list	[]
lifecycle	object	{}	Container lifecycle hooks for the node-cache pod.
nameOverride	string	""
podAnnotations	object	{}
podLabels	object	{}
prometheusScraping.enabled	bool	true
resizePolicy	list	[]	Resize policy for in-place pod vertical scaling. Container resize policies
resources.limits.memory	string	"128Mi"
resources.requests.cpu	string	"25m"
resources.requests.memory	string	"128Mi"
securityContext.capabilities.add[0]	string	"NET_ADMIN"
service.annotations	object	{}	Annotations to add to the service.
serviceAccount.annotations	object	{}	Annotations to add to the service account.
serviceAccount.create	bool	true	Specifies whether a service account should be created.
serviceAccount.name	string	""	If not set and create is true, a name is generated using the fullname template.
serviceMonitor	object	{"enabled":false,"honorLabels":false,"labels":{},"metricRelabelings":[],"namePrefix":"","path":"/metrics","prometheusNamespace":"kube-system","relabelings":[]}	https://github.com/prometheus-operator/prometheus-operator/blob/main/Documentation/user-guides/getting-started.md
serviceMonitor.enabled	bool	false	Ensure that servicemonitor is created, this will disable prometheus annotations
serviceMonitor.metricRelabelings	list	[]	Metric relabel configs to apply to samples before ingestion. Metric Relabeling
serviceMonitor.namePrefix	string	""	The service monitor name prefix which align with the prometheus operator name, eg.: kube-prometheus-stack
serviceMonitor.prometheusNamespace	string	"kube-system"	The namespace of prometheus where the service monitor should be deployed
serviceMonitor.relabelings	list	[]	Relabel configs to apply to samples before ingestion. Relabeling
tolerations[0].key	string	"CriticalAddonsOnly"
tolerations[0].operator	string	"Exists"
tolerations[1].effect	string	"NoExecute"
tolerations[1].operator	string	"Exists"
tolerations[2].effect	string	"NoSchedule"
tolerations[2].operator	string	"Exists"
updateStrategy	object	{"rollingUpdate":{"maxUnavailable":"10%"},"type":"RollingUpdate"}	DaemonSet update strategy configuration

Maintainers

Name	Email	Url
gabrieladt		https://github.com/gabrieladt

Chart source and versions

Chart source: github.com/deliveryhero/helm-charts/node-local-dns

Older chart versions: github.com/deliveryhero/helm-charts/pkgs/container/helm-charts/node-local-dns