2017-12-08 16:17:16 +08:00
|
|
|
|
## 部署 kubedns
|
|
|
|
|
|
|
|
|
|
|
|
kubedns 是 k8s 集群首先需要部署的，集群中的其他 pods 使用它提供域名解析服务；主要可以解析 `集群服务名` 和 `Pod hostname`；
|
|
|
|
|
|
|
|
|
|
|
|
配置文件参考 `https://github.com/kubernetes/kubernetes` 项目目录 `kubernetes/cluster/addons/dns`
|
|
|
|
|
|
|
|
|
|
|
|
### 安装
|
|
|
|
|
|
|
2017-12-08 17:43:51 +08:00
|
|
|
|
**kubectl create -f /etc/ansible/manifests/kubedns/[kubedns.yaml](../../manifests/kubedns/kubedns.yaml)**
|
|
|
|
|
|
|
|
|
|
|
|
+ 注意deploy中使用的 serviceAccount `kube-dns`，该预定义的 ClusterRoleBinding system:kube-dns 将 kube-system 命名空间的 kube-dns ServiceAccount 与 system:kube-dns ClusterRole 绑定， 因此POD 具有访问 kube-apiserver DNS 相关 API 的权限；
|
|
|
|
|
|
+ 集群 pod默认继承 node的dns 解析，修改 kubelet服务启动参数 --resolv-conf=""，可以更改这个特性，详见 kubelet 启动参数
|
|
|
|
|
|
|
|
|
|
|
|
### 验证 kubedns
|
|
|
|
|
|
|
|
|
|
|
|
新建一个测试nginx服务
|
|
|
|
|
|
|
|
|
|
|
|
`kubectl run nginx --image=nginx --expose --port=80`
|
|
|
|
|
|
|
|
|
|
|
|
确认nginx服务
|
|
|
|
|
|
|
|
|
|
|
|
``` bash
|
|
|
|
|
|
kubectl get pod|grep nginx
|
|
|
|
|
|
nginx-7cbc4b4d9c-fl46v 1/1 Running 0 1m
|
|
|
|
|
|
kubectl get svc|grep nginx
|
|
|
|
|
|
nginx ClusterIP 10.68.33.167 <none> 80/TCP 1m
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
测试pod busybox
|
|
|
|
|
|
|
|
|
|
|
|
``` bash
|
|
|
|
|
|
kubectl run busybox --rm -it --image=busybox /bin/sh
|
|
|
|
|
|
If you don't see a command prompt, try pressing enter.
|
|
|
|
|
|
/ # cat /etc/resolv.conf
|
|
|
|
|
|
nameserver 10.68.0.2
|
|
|
|
|
|
search default.svc.cluster.local. svc.cluster.local. cluster.local.
|
|
|
|
|
|
options ndots:5
|
|
|
|
|
|
# 测试集群内部服务解析
|
|
|
|
|
|
/ # nslookup nginx
|
|
|
|
|
|
Server: 10.68.0.2
|
|
|
|
|
|
Address 1: 10.68.0.2 kube-dns.kube-system.svc.cluster.local
|
|
|
|
|
|
|
|
|
|
|
|
Name: nginx
|
|
|
|
|
|
Address 1: 10.68.33.167 nginx.default.svc.cluster.local
|
|
|
|
|
|
/ # nslookup kubernetes
|
|
|
|
|
|
Server: 10.68.0.2
|
|
|
|
|
|
Address 1: 10.68.0.2 kube-dns.kube-system.svc.cluster.local
|
|
|
|
|
|
|
|
|
|
|
|
Name: kubernetes
|
|
|
|
|
|
Address 1: 10.68.0.1 kubernetes.default.svc.cluster.local
|
|
|
|
|
|
# 测试外部域名的解析，默认集成node的dns解析
|
|
|
|
|
|
/ # nslookup www.baidu.com
|
|
|
|
|
|
Server: 10.68.0.2
|
|
|
|
|
|
Address 1: 10.68.0.2 kube-dns.kube-system.svc.cluster.local
|
|
|
|
|
|
|
|
|
|
|
|
Name: www.baidu.com
|
|
|
|
|
|
Address 1: 180.97.33.108
|
|
|
|
|
|
Address 2: 180.97.33.107
|
|
|
|
|
|
/ #
|
|
|
|
|
|
```
|
2017-12-08 16:17:16 +08:00
|
|
|
|
|
2017-12-10 22:35:01 +08:00
|
|
|
|
[后一篇](dashboard.md) -- [目录](index.md)
|
