在学习coredns部署时出现了这种情况
在Pod外部,即集群宿主机上是没问题的
# nslookup cassandra.default.svc.cluster.local 10.96.0.10
Server: 10.96.0.10
Address: 10.96.0.10#53Name: cassandra.default.svc.cluster.local
Address: 10.97.200.71
但在Pod内部进行时,就出现了问题,虽然能够找到默认的coredns,但是解析不出IP地址
/ # nslookup cassandra
Server: 10.96.0.10
Address: 10.96.0.10:53** server can't find cassandra.default.svc.cluster.local: NXDOMAIN
*** Can't find cassandra.svc.cluster.local: No answer
*** Can't find cassandra.cluster.local: No answer
*** Can't find cassandra.Node1: No answer
*** Can't find cassandra.default.svc.cluster.local: No answer
*** Can't find cassandra.svc.cluster.local: No answer
*** Can't find cassandra.cluster.local: No answer
*** Can't find cassandra.Node1: No answer
后经测试是我使用的busybox镜像不太对,这个镜像的nslookup工具出现了问题。
# kubectl exec -it util-pod /bin/sh
/ # ping cassandra
PING cassandra (10.97.200.71): 56 data bytes
解决方法:更改镜像
infoblox/dnstools或者busybox:1.28.3
dnstools# nslookup cassandra
Server: 10.96.0.10
Address: 10.96.0.10#53Name: cassandra.default.svc.cluster.local
Address: 10.97.200.71dnstools#