Centos7 rc.loca添加自启动不生效的问题
背景：
我自己写了一个mongodb启动的shell脚本startMongoDB.sh
cat /opt/mongodb/bin/startMongoDB.sh #内容如下
/#!/bin/bash
mongod --config /opt/mongodb/mongodb.conf
然后在/etc/rc.d/rc.local中添加了启动项（如果是Unbuntu系统，则自己在/etc/init.d/目录下创建自启动脚本）
重启后发现无法启动，脚本内容如下：
# cat /etc/rc.d/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
/opt/mongodb/bin/startMongoDB.sh
尝试逐步排查下列可能导致启动失败的情况
rc.loca权限是否满足
# ls -l /etc/rc.d/rc.local
-rw-r--r--. 1 root root 523 Jun 11 00:45 /etc/rc.d/rc.local
如果没有执行权限，需要增加执行权限
# chmod u+x rc.local
-rwxr--r--. 1 root root 523 Jun 11 00:45 rc.local
reboot发现重启仍然没有生效
查看系统日志看能否找到错误信息
cat /var/log/message | grep rc.local
找到相关错误信息
Jun 11 02:56:36 localhost systemd: Starting /etc/rc.d/rc.local Compatibility...
Jun 11 02:56:36 localhost rc.local: /opt/mongodb/bin/startMongo.sh: line 3: mongod: command not found
Jun 11 02:56:36 localhost systemd: rc-local.service: control process exited, code=exited status=127
原因找到了，日志提示 mongod 命令无法识别。
修改startMongo.sh脚本，启动命令mongod改为使用绝对路径“/opt/mongodb/bin/mongod”：
vi /opt/mongodb/bin/startMongoDB.sh
/#!/bin/bash
/opt/mongodb/bin/mongod --config /opt/mongodb/mongodb.conf
reboot重启，问题解决。