问题： 在pod内无法解析域名
解决：
busybox的镜像有bug，导致ping可以解析，但是nslookup无法解析
kubectl run -it --rm --image=infoblox/dnstools dns-client
换成上面的就可以，实在解决不了再看下面的
dnstools# nslookup kubernetes
方式一：
创建coredns.yaml 要用hostwork模式，hostwork就是用的宿主机的 服务器IP端口
cluster-dns 指定成宿主机的
然后重启kubelet
然后重新创建pod
修改/etc/resolv.conf
[root@lab3 kubernetes]# kubectl get po -o wide -n kube-system
NAME READY STATUS RESTARTS AGE IP NODE
coredns-6d9f9c4fc9-2h652 1/1 Running 0 1h 10.1.1.111 10.1.1.111
coredns-6d9f9c4fc9-6prhs 1/1 Running 0 1h 10.1.1.68 10.1.1.68
修改三台的 宿主机的 resolv.conf 都改成 10.1.1.111
[root@lab2 kubernetes]# cat /etc/resolv.conf
# Generated by NetworkManager
search openstacklocal
nameserver 10.1.1.111
修改三台的,改成各自对应的宿主机的ip地址
[root@lab2 kubernetes]# cat kubelet
KUBELET_HOSTNAME="--hostname-override=10.1.1.68"
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.1"
KUBELET_CONFIG="--config=/etc/kubernetes/kubelet-config.yml"
KUBELET_ARGS="--bootstrap-kubeconfig=/etc/kubernetes/kubelet-bootstrap.conf --kubeconfig=/etc/kubernetes/kubelet.conf --cert-dir=/etc/kubernetes/pki --network-plugin=cni --cni-bin-dir=/opt/cni/bin --cni-conf-dir=/etc/cni/net.d --cluster-dns=10.1.1.68 --cluster-domain=cluster.local "
在cul容器内部访问
[ root@curl-87b54756-tsnwd:/ ]$ curl example-service.default.svc.cluster.local
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
在外部主机访问
[root@lab2 kubernetes]# curl example-service.default.svc.cluster.local
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
但是访问下面短的 还是不行
[root@lab3 kubernetes]# curl example-service
curl: (6) Could not resolve host: example-service; Unknown error
解决办法，指点：搜索域有问题，
他的是搜索域的问题
在busybox里面可以访问短的域名
[root@lab2 kubernetes]# kubectl run -it --rm --image=infoblox/dnstools dns-client
If you don't see a command prompt, try pressing enter.
dnstools#
dnstools#
dnstools# curl example-service
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
方式二：
新版本自然解决：
流程：
1、删除原先coredns的配置
2、部署coredns
3. 删除原先的pod、service、重新创建，
#!/bin/bash
wget https://raw.githubusercontent.com/coredns/deployment/master/kubernetes/coredns.yaml.sed
wget https://raw.githubusercontent.com/coredns/deployment/master/kubernetes/deploy.sh
chmod +x deploy.sh
./deploy.sh -i 10.96.0.10 -d cluster.local. > dns.yaml
kubectl apply -f dns.yaml;
--cluster-dns=10.1.1.8 --cluster-domain=cluster.local"
在外边访问service ，那是另外一个问题了啊！但是首先你cluster 中 DNS的IP 不应拿hostip 来顶住哦
可以把内部的cluster ip 再用其他的代理 代理出来，里边的还是用 一个clusterip
#!/bin/bash
export http_proxy=
export https_proxy=
wget https://raw.githubusercontent.com/coredns/deployment/master/kubernetes/coredns.yaml.sed
wget https://raw.githubusercontent.com/coredns/deployment/master/kubernetes/deploy.sh
chmod +x deploy.sh
./deploy.sh -i 10.254.0.2 -d cluster.local. > dns.yaml
kubectl apply -f dns.yaml;
16:30:50
[root@lab3 kubernetes]# netstat -anp |grep 53
tcp 0 0 10.1.1.111:10250 10.1.1.8:53506 ESTABLISHED 32337/kubelet
tcp6 0 0 :::53 :::* LISTEN 25791/coredns
tcp6 0 0 :::9153 :::* LISTEN 25791/coredns
udp6 0 0 :::53 :::* 25791/coredns
unix 2 [ ACC ] STREAM LISTENING 15097 653/NetworkManager /var/run/NetworkManager/private-dhcp
unix 3 [ ] STREAM CONNECTED 20544 653/NetworkManager
unix 2 [ ] DGRAM 15853 508/systemd-udevd
unix 2 [ ] DGRAM 20239 653/NetworkManager
unix 3 [ ] STREAM CONNECTED 20979 653/NetworkManager
unix 3 [ ] STREAM CONNECTED 20983 653/NetworkManager
[ root@curl-87b54756-782kr:/ ]$ nslookup example-service
Server: 10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
Name: example-service
Address 1: 10.104.125.95 example-service.default.svc.cluster.local
[ root@curl-87b54756-782kr:/ ]$ curl example-service
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
