Single-user mode, rescue mode, clone virtual machine, Linux machine login to each other

Single-user mode

When we forget our server's password we can go into single-user mode on our server

Modify our Password: The premise is that we have to operate the physical machine of the host, remote login is not possible!!

The single-user mode enters grub only if we don't have the password set in grub, otherwise using single-user mode will not work

Forgot grub Password Enter optical drive rescue mode

Step (Single user mode): Restart Linux (under VMware we right-click Virtual machine)--"power--" Restart the client--"Select the first item that appears on the screen---" press the E key as prompted (enter into Grub mode, Grub is found on the system boot disk)--"press the DOWN ARROW key to move the cursor to the linux16 and then the back arrow key to the RO to modify

What to modify:

RO: Read-only RW: Read/write

Init=/sysroot/bin/sh directory where the original system resides

After modification, press the reminder at the same time: Ctrl+x into Safe mode

Command: Chroot/sysroot

lang=en

passwd Root

Touch/.autorelabel

Finally restart the client

Second, rescue mode

Forgot grub Password Enter optical drive rescue mode

Step: First step Off (init 0)

--"Edit the settings of our virtual machines

Select Power-"/enter firmware when power is on (to load the optical drive at startup)

The arrow key left and right to select boot, the purpose is that we put CD-ROM drive in the first item (using "-" number)

Then press F10 to exit.

After automatic restart, select the third carriage return and enter the

Select Rescue a CentOS system carriage return

--》

The chroot/mnt/sysimage here are the same as the chroot/sysroot/above, and they are all orders to get into our original system.

P

Finally, change the boot CD-ROM under BIOS before restarting

or direct: Click on the small drive in the lower right corner of VMware to connect the CD-ROM drive and cancel the connection at startup

Restarting the client can

Cloning a virtual machine

Step: Right-click on the virtual machine------"next to create a linked clone continue to the next step to completion

After completing the login

Modify IP (because the cloned virtual machine IP is the same, the use will be problematic)

Vi/ect/sysconfig/network-scripts/ifcfg-ens33

Restart the network service when you are finished editing:

Systemctl Restart Network.service

To ping again, whether or not to pass

Set host name: Easy to distinguish

Hostnamectl Set-hostname Cansheng2

You can then use Pttuy and Xshell to connect the

Linux machines log in to each other

A (cansheng2) connection B (cansheng1)

command: SSH [email protected] (here root can be omitted, is the default system currently logged on users)

Format: SSH [email protected] IP (Linux under connect command)

Ssh-p Port [email protected] IP

You can also log in with a key

Command:

Ssh-keygen

Here the generated file path can be specified, password can also be set (I do not fill in the default)

Copy the A (cansheng2) public key to the/root/.ssh/authorized_keys of B

(a machine to log in B, you want to copy the public key from the A machine to the B machine configuration file)

Connect again is the key pair connection (, here I do not set the password so login does not require a password)

Single-user mode, rescue mode, clone virtual machine, Linux machine login to each other