Enter single user mode under CentOS7

Enter single user mode under CentOS7

Centos7 uses grub2, which is different from centos6.x for single-user access. However, because it is not possible to use a real machine environment, it is just a rough description of the following ideas.

Init Method

1. The grub2 interface of centos7 has two entrances: normal system entrance and rescue mode;

2. Modify grub2 boot

Press "e" on the normal system portal to enter the edit mode. Search for the ro line starting with linux16;

Change ro to rw (Change read-only to writable)

Delete the rhgb quiet. (The quiet mode can be deleted if the code line does not exist)

Add init =/bin/sh; (or init =/bin/bash, specify the shell environment)

Press ctrl + x to start the system.

3. Modify the root password

# Passwd # change the password

# Touch/. autorelabel # It is said that selinux updated the label after restarting

# Exec/sbin/init # Start the init process normally

There is also a rd. break method (not tried)

1. at startup, on the startup interface, press "e" on the corresponding startup Item and kernel name ";

2. After Entering, find the place starting with linux16, press the "end" Key to the end, enter rd. break, and press ctrl + x to enter;

3. Enter the mount command and find that the root is/sysroot/and cannot be written. Only the ro = readonly permission is required;

4. mount-o remount, rw/sysroot/, re-mount, and then mount, and find that the r and w permissions are available;

5. Change the root of chroot/sysroot;

(1) echo redhat | passwd-stdin root: Change the root password to redhat, or enter passwd for interactive modification;

(2) cp and then modify the/etc/shadow file.

6. touch/. autorelabel takes effect for selinux.

7. Press ctrl + d to exit

8. Then reboot