使用kt-connetct实现k8s网络互通

KtConnect介绍：阿里开源的k8s的调试工具，它的作用类似于VPN，实现了开发者本地运行的服务与Kubernetes集群中的服务之间的双向互通。

https://github.com/alibaba/kt-connect

KT: A simple kubernetes development tools

前置条件：在需要访问k8s内部网络的lcentos安装kubectl，并配置好集群证书。

kubectl create deployment nginx -n lishanbin-public-servcie  --image=registry.cn-shenzhen.aliyuncs.com/lishanbin/nginx:1.0.0 --port=80

kubectl expose deployment nginx -n lishanbin-public-servcie --port=80 --target-port=80

查询Pod和服务的IP地址：

[app@master1 yaml]$ kubectl get svc  -n lishanbin-public-servcie 
NAME    TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
nginx   ClusterIP   10.207.136.215           80/TCP    3m31s
[app@master1 yaml]$ kubectl get pod -n lishanbin-public-servcie -o wide 
NAME                     READY   STATUS    RESTARTS   AGE     IP              NODE              NOMINATED NODE   READINESS GATES
nginx-6698c59b8f-lvjbn   1/1     Running   0          7m33s   10.206.36.203   11.12.13.14              

可知nginx实例的Pod IP为10.206.36.203，服务的Cluster IP为10.207.136.215，记下待用。

$ curl -OL https://github.com/alibaba/kt-connect/releases/download/v0.3.5-beta1/ktctl_0.3.5-beta1_Linux_x86_64.tar.gz
$ tar zxf ktctl_0.3.5-beta1_Linux_x86_64.tar.gz
$ mv ktctl /usr/local/bin/ktctl
$ ktctl help

ktctl connect
11:35AM INF Using cluster context local (local)
11:35AM INF KtConnect 0.3.5-beta1 start at 22081 (linux amd64)
11:35AM INF Fetching cluster time ...
11:35AM INF Successful create config map kt-connect-shadow-radtu
11:35AM INF Deploying shadow pod kt-connect-shadow-radtu in namespace default
11:35AM INF Waiting for pod kt-connect-shadow-radtu ...
11:36AM INF Pod kt-connect-shadow-radtu is ready
11:36AM INF Port forward local:16737 -> pod kt-connect-shadow-radtu:22 established
11:36AM INF Socks proxy established
11:36AM INF Tun device kt0 is ready
11:36AM INF Adding route to 10.207.0.0/16
11:36AM INF Adding route to 10.206.0.0/16
11:36AM INF Route to tun device completed
11:36AM INF Setting up dns in local mode
11:36AM INF Port forward local:11083 -> pod kt-connect-shadow-radtu:53 established
11:36AM INF Setup local DNS with upstream [tcp:127.0.0.1:11083 udp:114.114.114.114:53]
11:36AM INF Creating udp dns on port 10053
11:36AM INF ---------------------------------------------------------------
11:36AM INF  All looks good, now you can access to resources in the kubernetes cluster
11:36AM INF ---------------------------------------------------------------

curl 10.206.36.203:80







Welcome to nginx! the version is 1.0.0  
If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.

For online documentation and support please refer to
nginx.org.

Commercial support is available at
nginx.com.

Thank you for using nginx.