1、原因：服务器重启后rsync服务没有起来，rsync启动已经写入/etc/rc.local中

2：分析：查看more /etc/rc.local

写启动内容没问题，也是全路径；查看 /etc/rc.local 文件，是一个链接，链接到 /etc/rc.d/rc.local，查看 /etc/rc.d/rc.local 文件，发现没有执行权限。

[root@master ~]# more /etc/rc.local

#!/bin/bash

# THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES

#

# It is highly advisable to create own systemd services or udev rules

# to run scripts during boot instead of using this file.

#

# In contrast to previous versions due to parallel execution during boot

# this script will NOT be run after all other services.

#

# Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure

# that this script will be executed during boot.

touch /var/lock/subsys/local

/usr/local/sersync/bin/sersync2 -r -d -o /usr/local/sersync/conf/confxml.xml

[root@master ~]#

[root@slave ~]# more /etc/rc.local

#!/bin/bash

# THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES

#

# It is highly advisable to create own systemd services or udev rules

# to run scripts during boot instead of using this file.

#

# In contrast to previous versions due to parallel execution during boot

# this script will NOT be run after all other services.

#

# Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure

# that this script will be executed during boot.

touch /var/lock/subsys/local

rsync --daemon --config=/etc/rsyncd.conf

[root@slave ~]#

3、加上执行权限之后，再重启发现服务自动起来了。

[root@master ~]# chmod +x /etc/rc.d/rc.local

[root@master ~]# ll /etc/rc.d/rc.local

-rwxr-xr-x. 1 root root 527 Aug 17 2022 /etc/rc.d/rc.local

[root@master ~]# reboot

[root@slave ~]# lsof -i:873

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

rsync 888 root 4u IPv4 21280 0t0 TCP *:rsync (LISTEN)

rsync 888 root 5u IPv6 21281 0t0 TCP *:rsync (LISTEN)

[root@slave ~]#

[root@slave ~]# netstat -lntup | grep rsync

tcp 0 0 0.0.0.0:873 0.0.0.0:* LISTEN 888/rsync

tcp6 0 0 :::873 :::* LISTEN 888/rsync

[root@slave ~]#