rke2 coredns 自定义配置
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本文永久链接: https://www.xtplayer.cn/rke2/rke2-coredns-custom-config/
在部署 rke2 集群后，会自动部署一个 cluster agent 服务去连接 rancher server。对于内部没有 dns 服务器的开发环境，这个时候查看 cluster agent pod 日志，就会出现以下的错误日志：
可能你在主机的 /etc/hosts 中配置了 HostAliases，但是因为 cluster agent 是 pod/容器运行，它无法读取到主机的 HostAliases。
为了避免 cluster agent 无法连接 rancher server 导致 rke2 集群不可用，rke2 增加了自定义 corends 配置的功能。
root@rke2-1:~
apiVersion: v1
data:
Corefile: ".:53 {\n errors \n health {\n lameduck 5s\n }\n ready
\n kubernetes cluster.local cluster.local in-addr.arpa ip6.arpa {\n pods
insecure\n fallthrough in-addr.arpa ip6.arpa\n ttl 30\n }\n prometheus
\ 0.0.0.0:9153\n forward . /etc/resolv.conf\n cache 30\n loop \n
\ reload \n loadbalance \n}"
kind: ConfigMap
metadata:
annotations:
meta.helm.sh/release-name: rke2-coredns
meta.helm.sh/release-namespace: kube-system
creationTimestamp: "2023-02-07T04:50:45Z"
labels:
app.kubernetes.io/instance: rke2-coredns
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: rke2-coredns
helm.sh/chart: rke2-coredns-1.19.401
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
kubernetes.io/name: CoreDNS
name: rke2-coredns-rke2-coredns
namespace: kube-system
resourceVersion: "1039432"
uid: 8ed55660-07f1-47cf-9acc-fae32a392d5b
root@rke2-1:~
|
apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
name: rke2-coredns
namespace: kube-system
spec:
valuesContent: |-
servers:
- zones:
- zone: .
port: 53
# If serviceType is nodePort you can specify nodePort here
# nodePort: 30053
plugins:
- name: hosts
configBlock: |-
1.2.3.4 www.xxx.com
- name: errors
# Serves a /health endpoint on :8080, required for livenessProbe
- name: health
configBlock: |-
lameduck 5s
# Serves a /ready endpoint on :8181, required for readinessProbe
- name: ready
# Required to query kubernetes API for data
- name: kubernetes
parameters: cluster.local in-addr.arpa ip6.arpa
configBlock: |-
pods insecure
fallthrough in-addr.arpa ip6.arpa
ttl 30
# Serves a /metrics endpoint on :9153, required for serviceMonitor
- name: prometheus
parameters: 0.0.0.0:9153
- name: forward
parameters: . /etc/resolv.conf
- name: cache
parameters: 30
- name: loop
- name: reload
- name: loadbalance
|
- 将配置保存为 yaml 文件，然后执行 kubectl apple -f xx.yaml
- 再次执行命令查看 coredns 配置文件:
root@rke2-1:~
apiVersion: v1
data:
Corefile: ".:53 {\n hosts {\n 1.2.3.4 www.xxx.com\n }\n errors
\n health {\n lameduck 5s\n }\n ready \n kubernetes cluster.local
\ cluster.local in-addr.arpa ip6.arpa {\n pods insecure\n fallthrough
in-addr.arpa ip6.arpa\n ttl 30\n }\n prometheus 0.0.0.0:9153\n
\ forward . /etc/resolv.conf\n cache 30\n loop \n reload \n loadbalance
\n}"
kind: ConfigMap
metadata:
annotations:
meta.helm.sh/release-name: rke2-coredns
meta.helm.sh/release-namespace: kube-system
creationTimestamp: "2023-02-07T04:50:45Z"
labels:
app.kubernetes.io/instance: rke2-coredns
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: rke2-coredns
helm.sh/chart: rke2-coredns-1.19.401
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
kubernetes.io/name: CoreDNS
name: rke2-coredns-rke2-coredns
namespace: kube-system
resourceVersion: "1048131"
uid: 8ed55660-07f1-47cf-9acc-fae32a392d5b
root@rke2-1:~
|
root@rke2-1:~# kubectl -n kube-system get pod -owide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
cloud-controller-manager-rke2-1 1/1 Running 15 (145m ago) 55d 192.168.31.141 rke2-1 <none> <none>
etcd-rke2-1 1/1 Running 8 (145m ago) 55d 192.168.31.141 rke2-1 <none> <none>
helm-install-rke2-calico-crd-m5rfm 0/1 Completed 0 55d 192.168.31.141 rke2-1 <none> <none>
helm-install-rke2-calico-s9wbg 0/1 Completed 1 55d 192.168.31.141 rke2-1 <none> <none>
helm-install-rke2-coredns-xjrn9 0/1 Completed 0 93s 192.168.31.141 rke2-1 <none> <none>
kube-apiserver-rke2-1 1/1 Running 8 (145m ago) 55d 192.168.31.141 rke2-1 <none> <none>
kube-controller-manager-rke2-1 1/1 Running 15 (145m ago) 55d 192.168.31.141 rke2-1 <none> <none>
kube-proxy-rke2-1 1/1 Running 8 (145m ago) 55d 192.168.31.141 rke2-1 <none> <none>
kube-scheduler-rke2-1 1/1 Running 8 (145m ago) 55d 192.168.31.141 rke2-1 <none> <none>
rke2-coredns-rke2-coredns-7c8d4b7fc-sp75s 1/1 Running 0 92s 10.42.172.95 rke2-1 <none> <none>
rke2-coredns-rke2-coredns-autoscaler-768bfc5985-kmvtg 1/1 Running 0 48m 10.42.172.83 rke2-1 <none> <none>
root@rke2-1:~# ping 10.42.172.95
PING 10.42.172.95 (10.42.172.95) 56(84) bytes of data.
64 bytes from 10.42.172.95: icmp_seq=1 ttl=64 time=0.077 ms
64 bytes from 10.42.172.95: icmp_seq=2 ttl=64 time=0.067 ms
^C
--- 10.42.172.95 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1009ms
rtt min/avg/max/mdev = 0.067/0.072/0.077/0.005 ms
root@rke2-1:~# nslookup www.xxx.com 10.42.172.95
Server: 10.42.172.95
Address: 10.42.172.95#53
Name: www.xxx.com
Address: 1.2.3.4
root@rke2-1:~#
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