kubectl 命令报错couldn't get current server API group list: ... connect: connection refused
kubenets在运行时，依赖环境变量。如果所有的服务都是正常的，只是kubectl命令报错，那就是环境变量没有设置导致。一般报错样例如下：
couldn't get current server API group list: Get "http://localhost:8080/api?timeout=32s": dial tcp [::1]:8080: connect: connection refused。The connection to the server localhost:8080 was refused - did you specify the right host or port?
解决方案
重新进入客户端，或者重新写 ~/.kube/config