Solve the problem that the KVM host cannot connect to the client through the console

Solve the problem that the KVM host cannot connect to the client through the console

I. Problem description:

The KVM host cannot connect to the client through the console, and it does not move here.

# Virsh console vm01

Connected to domain vm01

Escape character is ^]

Add virsh console support for KVM clients

Ii. Solution: Use vnc or host desktop to enter the client vm01 and add Parameters

1. Add a security license for ttyS0 to allow root login:

# Echo "ttyS0">/etc/securetty

2. Add parameters to the kernel in the/etc/grub. conf file:

Console = ttyS0

Note:

Console = ttyS0 must be placed in the kernel line (about 16th rows). It cannot be a single line. That is, console = ttyS0 is a parameter of the kernel, not a separate line, as shown in the following figure (pull the progress bar to the right, at the end ):

# Cat-n/etc/grub. conf

# Grub. conf generated by anaconda

#

# Note that you do not have to rerun grub after making changes to this file

# NOTICE: You have a/boot partition. This means that

# All kernel and initrd paths are relative to/boot/, eg.

# Root (hd0, 0)

# Kernel/vmlinuz-version ro root =/dev/mapper/VolGroup-lv_root

# Initrd/initrd-[generic-] version. img

# Boot =/dev/vda

Default = 0

Timeout = 5

Splashimage = (hd0, 0)/grub/splash.xpm.gz

Hiddenmenu

Title Red Hat Enterprise Linux (2.6.32-431. el6.x86 _ 64)

Root (hd0, 0)

Kernel/vmlinuz-2.6.32-431.el6.x86_64 ro root =/dev/mapper/VolGroup-lv_root kernel LANG = en_US.UTF-8 rd_NO_MD kernel = VolGroup/lv_swap SYSFONT = latarcyrheb-sun16 crashkernel = auto kernel = VolGroup/lv_root KEYBOARDTYPE = pc KEYTABLE = us rd_NO_DM rhgb quiet console = ttyS0

Initrd/initramfs-2.6.32-431.el6.x86_64.img

3. Add agetty in the/etc/inittab:

S0: 12345: respawn:/sbin/agetty ttyS0 115200

4. Restart the client:

# Reboot

Iii. Problem Solving

# Virsh console vm01

Connected to domain vm01

Escape character is ^]

Red Hat Enterprise Linux Server release 6.5 (Santiago)

Kernel 2.6.32-431. el6.x86 _ 64 on an x86_64

 

Vm01 login: root

Password:

Last login: Sun Oct 12 00:11:47 on tty1

[Root @ vm01 ~] #

Appendix: summary of the basic concepts of terminals:

Tty (collectively referred to as the terminal device ):

Tty is derived from Teletypes or teletypewriters. Originally, it refers to a telex typewriter, which reads and sends messages through a printer keyboard through a serial line. Later, it was replaced by a keyboard and a display, so now it is more appropriate to call the terminal.

A terminal is a type of terminal device. It has multiple types and generally uses tty for short.

Pty (Pseudo Terminal, virtual terminal ):

But if we remotely telnet to the host or use xterm, do we still need a terminal to interact? Yes, this is the virtual terminal pty (pseudo-tty)

Pts/ptmx (combining pts/ptmx to implement pty ):

Pts (pseudo-terminal slave) is the implementation method of pty. It is used with ptmx (pseudo-terminal master) to implement pty.

For more details, please continue to read the highlights on the next page:

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