使用rsync往不同的机器同步数据的时候，出现了如下错误

bash: rsync: command not found
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: remote command not found (code 127) at io.c(226) [sender=3.1.2]

造成此问题的原因是被同步的机器也要安装rsync，运行以下命令安装

yum  install rsync -y

目标机器安装完成后，回到源机器再次使用rsync尝试同步已经可以成功同步！

[root@centos cert]# rsync -av /usr/local/cert/ root@192.168.1.101:/home/cert
sending incremental file list
./
3188136_orcy.net.cn.key
3188136_orcy.net.cn.pem

sent 19,473 bytes  received 281 bytes  39,508.00 bytes/sec
total size is 25,994  speedup is 1.32