Kubernetes CoreDNS

CozyFex included in kubernetes k8s orchestration network cluster dns coredns

2021-05-31 163 words One minute

Contents

CoreDNS

CoreDNS is a DNS server.
It is written in Go.
It can be used in a multitude of environments because of its flexibility.

Configuration File Location

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kubectl -n kube-system describe deploy coredns | grep -C2 -i args

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    Ports:       53/UDP, 53/TCP, 9153/TCP
    Host Ports:  0/UDP, 0/TCP, 0/TCP
    Args:
      -conf
      /etc/coredns/Corefile

Corefile

CoreDNS is passing Corefile as a ConfigMap to the PODs of CoreDNS.

Show CoreDNS ConfigMap

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kubectl -n kube-system describe cm coredns

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Name:         coredns
Namespace:    kube-system
Labels:       <none>
Annotations:  <none>

Data
====
Corefile:
----
.:53 {
    errors
    health {
       lameduck 5s
    }
    ready
    kubernetes cluster.local in-addr.arpa ip6.arpa {
       pods insecure
       fallthrough in-addr.arpa ip6.arpa
       ttl 30
    }
    prometheus :9153
    forward . /etc/resolv.conf {
       max_concurrent 1000
    }
    cache 30
    loop
    reload
    loadbalance
}

Events:  <none>