部署完etcd后检查了集群健康状态为正常状态，但是使用etcd命令行工具 etcdctl 却报错
报错截图如下：
报错信息文本内容粘贴如下：
Error: client: etcd cluster is unavailable or misconfigured; error #0: x509: certificate signed by unknown authority
; error #1: x509: certificate signed by unknown authority
; error #2: x509: certificate signed by unknown authority
error #0: x509: certificate signed by unknown authority
error #1: x509: certificate signed by unknown authority
error #2: x509: certificate signed by unknown authority
查看环境变量ETCDCTL_API的值 为空
手动设置环境变量 export ETCDCTL_API=3
再执行etcdctl命令不再报错
