Reasons and solutions for CentOS7 booting into emergency mode

    1. After modifying the /etc/fstab file, "welcome to emergency mode! after logging in type "journalctl -xb" to view system logs..." appears.
    2. Possible reasons: Unable to recognize the file system to be mounted
    3. Solution: Delete the boot mount content that you added after the /etc/fstab file. For
    example: I added /usr/local/src/CentOS-7.0-1406-x86_64-Everything.iso when making a local yum source /media/CentOS7-LocalSource iso9660 defaults,ro,loop 0 0
    "welcome to emergency mode! after logging in type "journalctl -xb"to view system logs..." appears when booting
    up reboot and you can enter the system normally