systemd management using systemctl and journalctl to check systemd logs
systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system.
The key commands or arguments you will use with systemctl are the following:
Unit Commands:
list-units [PATTERN...] List loaded units
&nbs........
MySQLD Server shutdown remotely unexpectedly
170110 5:35:23 [Note] /usr/libexec/mysqld: Normal shutdown
170110 5:35:23 [Note] Event Scheduler: Purging the queue. 0 events
170110 5:35:23 InnoDB: Starting shutdown...
170110 5:35:24 InnoDB: Shutdown completed; log sequence number 0 12765401
170110 5:35:24 [Note] /usr/libexec/mysqld: Shutdown complete
170110 05:35:24 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended........
Linux Kernel Freeze/Hang during boot on io scheduler cfq registered (default)
You'll see the following and the boot process will freeze:
io scheduler noop registered
io scheduler anticipatory registered
io scheduler deadline registered
io scheduler cfq registered (default)
I have struggled with this issue on vari........