/var/log/messages中没有日志

 修改syslog配置文件并重启

sudo vi /etc/rsyslog.conf

找到此行：#$ModLoad imklog # reads kernel messages (the same are read from journald)
修改为：$ModLoad imklog # reads kernel messages (the same are read from journald)
找到此行：$OmitLocalLogging on
修改为：#$OmitLocalLogging on
找到此行：$IMJournalStateFile imjournal.state
修改为：#$IMJournalStateFile imjournal.state
重启日志服务：sudo systemctl restart rsyslog
sudo tail -f /var/log/messages  发现有输入信息了 

centos7默认$ModLoad imklog # reads kernel messages (the same are read from journald)是注释的