Kubernetes (K8S)集群中pod内部的"nslookup: read: Connection refused“(DNS问题)
问题
我在基于CentOS7的AWS ec2上有一个带有1个主服务器和1个节点的k8s集群的自定义安装。当调用nslookup google.com时，它在节点pod内使用核心DNS(pod运行正常，日志中没有错误)，输出为nslookup: write to '10.96.0.10': Connection refused ;; connection timed out; no servers could be reached
例如，在pod ping 8.8.8.8内执行fine命令就可以正常工作：
PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: seq=0 ttl=50 time=1.330 mspod中的/etc/resolv.conf如下所示：
nameserver 10.96.0.10
search default.svc.cluster.local svc.cluster.local cluster.local ec2.internal
options ndots:5此命令在节点本身的nslookup google.com中运行良好
Server: 172.31.0.2
Address: 172.31.0.2#53
Non-authoritative answer:
Name: google.com
Address: 172.217.15.110
Name: google.com
Address: 2607:f8b0:4004:801::200eKubelet配置kubectl get configmap kubelet-config-1.17 -n kube-system -o yaml返回
data:
kubelet: |
apiVersion: kubelet.config.k8s.io/v1beta1
authentication:
anonymous:
enabled: false
webhook:
cacheTTL: 0s
enabled: true
x509:
clientCAFile: /etc/kubernetes/pki/ca.crt
authorization:
mode: Webhook
webhook:
cacheAuthorizedTTL: 0s
cacheUnauthorizedTTL: 0s
clusterDNS:
- 10.96.0.10
clusterDomain: cluster.local
cpuManagerReconcilePeriod: 0s
evictionPressureTransitionPeriod: 0s
fileCheckFrequency: 0s
healthzBindAddress: 127.0.0.1
healthzPort: 10248
httpCheckFrequency: 0s
imageMinimumGCAge: 0s
kind: KubeletConfiguration
nodeStatusReportFrequency: 0s
nodeStatusUpdateFrequency: 0s
rotateCertificates: true
runtimeRequestTimeout: 0s
staticPodPath: /etc/kubernetes/manifests
streamingConnectionIdleTimeout: 0s
syncFrequency: 0s
volumeStatsAggPeriod: 0s
kind: ConfigMapkube命名空间kubectl get pods -n kube-system中的Pods如下所示：
coredns-6955765f44-qdbgx 1/1 Running 6 11d
coredns-6955765f44-r4v7n 1/1 Running 6 11d
etcd-ip-172-31-42-121.ec2.internal 1/1 Running 7 11d
kube-apiserver-ip-172-31-42-121.ec2.internal 1/1 Running 7 11d
kube-controller-manager-ip-172-31-42-121.ec2.internal 1/1 Running 6 11d
kube-proxy-lrpd9 1/1 Running 6 11d
kube-proxy-z55cv 1/1 Running 6 11d
kube-scheduler-ip-172-31-42-121.ec2.internal 1/1 Running 6 11d
weave-net-bdn5n 2/2 Running 0 39h
weave-net-z7mks 2/2 Running 5 39h更新
在pod中，如果我执行ip route，它将返回：
default via 10.32.0.1 dev eth0
10.32.0.0/12 dev eth0 scope link src 10.32.0.16 来自master：
default via 172.31.32.1 dev eth0
10.32.0.0/12 dev weave proto kernel scope link src 10.32.0.1
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1
172.31.32.0/20 dev eth0 proto kernel scope link src 172.31.42.121 发件人节点：
default via 172.31.32.1 dev eth0
10.32.0.0/12 dev weave proto kernel scope link src 10.32.0.1
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1
172.31.32.0/20 dev eth0 proto kernel scope link src 172.31.46.62 CoreDNS配置映射kubectl -n kube-system get configmap coredns -oyaml为：
apiVersion: v1
data:
Corefile: |
.:53 {
log
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
cache 30
loop
reload
loadbalance
}
kind: ConfigMap那么为什么nslookup google.com不能在pod中工作呢？
回答 1
Stack Overflow用户
发布于 2020-04-14 04:39:09
k8s群集安装错误，可能的脚本应包含ec2虚拟机上的主服务器和节点的正确内网IP。
dev-kubernetes-master ansible_host=34.233.207.xxx private_ip=172.31.37.xx
dev-kubernetes-slave ansible_host=52.6.10.xxx private_ip=172.31.42.xxx我已经重新安装了指定了正确内网ip的集群(在没有内网ip之前)，问题已经解决了。
https://stackoverflow.com/questions/61140524
复制相似问题
腾讯云开发者
Copyright © 2013 - 2026 Tencent Cloud. All Rights Reserved. 腾讯云 版权所有
深圳市腾讯计算机系统有限公司 ICP备案/许可证号：粤B2-20090059 
粤公网安备44030502008569号
腾讯云计算（北京）有限责任公司 京ICP证150476号 | 京ICP备11018762号