001、nodelocaldns(/etc/resolv.conf)

nodelocaldns  pod 中的 /etc/resolv.conf 虽然读取的是 宿主机的/etc/resolv.conf，但是不是实时同步更新的。可能同步更新会有延迟

所以如果  /etc/resolv.conf 文件中的内容

[root@master-01 kubernetes]#  kubectl -n kube-system exec node-local-dns-lw7mh -it -- cat /etc/resolv.conf
nameserver 10.10.10.1
nameserver 10.10.10.2
nameserver 114.114.114.114
options single-request-reopen
[root@master-01 kubernetes]# kubectl delete -f nodelocaldns.yaml 
serviceaccount "node-local-dns" deleted
service "kube-dns-upstream" deleted
configmap "node-local-dns" deleted
daemonset.apps "node-local-dns" deleted
service "node-local-dns" deleted
[root@master-01 kubernetes]# kubectl apply -f nodelocaldns.yaml 
serviceaccount/node-local-dns created
service/kube-dns-upstream created
configmap/node-local-dns created
daemonset.apps/node-local-dns created
service/node-local-dns created
[root@master-01 kubernetes]# kubectl get pods -A -owide|grep loc
kube-system   node-local-dns-fn9wt                                                  1/1     Running   0             11s   192.168.1.13   master-03   <none>           <none>
kube-system   node-local-dns-hb4kh                                                  1/1     Running   0             11s   192.168.1.11   master-01   <none>           <none>
kube-system   node-local-dns-pdbsq                                                  1/1     Running   0             11s   192.168.1.14   node-01     <none>           <none>
kube-system   node-local-dns-th4bh                                                  1/1     Running   0             11s   192.168.1.12   master-02   <none>           <none>
[root@master-01 kubernetes]#  kubectl -n kube-system exec node-local-dns-fn9wt -it -- cat /etc/resolv.conf
nameserver 127.0.0.1
nameserver 192.168.3.56
nameserver 10.10.10.2
options single-request-reopen
[root@master-01 kubernetes]# cat /etc/resolv.conf
options timeout:1
options single-request-reopen
nameserver 127.0.0.1
nameserver 192.168.3.56
nameserver 10.10.10.2