[FAQ] Coredns启动失败
coredns pod status is CrashLoopBackOff
$ kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-fb8b8dccf-cl9rp 0/1 CrashLoopBackOff 6 10m
coredns-fb8b8dccf-v4lsv 0/1 CrashLoopBackOff 6 10m
etcd-pytimer 1/1 Running 0 9m24s
kube-apiserver-pytimer 1/1 Running 0 9m21s
kube-controller-manager-pytimer 1/1 Running 0 9m24s
kube-flannel-ds-amd64-84vxg 1/1 Running 0 8m14s
kube-proxy-cgqpn 1/1 Running 0 10m
kube-scheduler-pytimer 1/1 Running 0 9m15s
查看coredns pod的日志，发现如下错误：
$ kubectl logs -n kube-system coredns-fb8b8dccf-cl9rp
.:53
2019-03-26T13:58:34.693Z [INFO] CoreDNS-1.3.1
2019-03-26T13:58:34.694Z [INFO] linux/amd64, go1.11.4, 6b56a9c
CoreDNS-1.3.1
linux/amd64, go1.11.4, 6b56a9c
2019-03-26T13:58:34.694Z [INFO] plugin/reload: Running configuration MD5 = 599b9eb76b8c147408aed6a0bbe0f669
2019-03-26T13:58:34.694Z [FATAL] plugin/loop: Loop (127.0.0.1:51824 -> :53) detected for zone ".", see https://coredns.io/plugins/loop#troubleshooting. Query: "HINFO 5012779829032833898.3830104233741532924."
查看宿主机上的dns配置
$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.1.1
search lan
更改nameserver，不使用127.0.1.1
修改/etc/NetworkManager/NetworkManager.conf，注释掉dns=dnsmasq
[main]
plugins=ifupdown,keyfile,ofono
#dns=dnsmasq
重启服务：service network-manager restart
可以看到coredns的pod正常启动
$ kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-fb8b8dccf-gctnk 1/1 Running 0 33s
coredns-fb8b8dccf-zx246 1/1 Running 0 33s
etcd-pytimer 1/1 Running 0 10m
kube-apiserver-pytimer 1/1 Running 0 10m
kube-controller-manager-pytimer 1/1 Running 0 10m
kube-flannel-ds-amd64-84vxg 1/1 Running 0 8m57s
kube-proxy-cgqpn 1/1 Running 0 10m
kube-scheduler-pytimer 1/1 Running 0 9m58s
