配置KVM宿主机使用vish console命令直接进入CentOS6虚拟机

在使用libvrit+virsh配置KVM虚拟机时，使用vish console ${domain}出现如下情况而不能进入虚拟机。

[root@kvm01 ~]# virsh console instance001
Connected to domain instance001
Escape character is ^]
Press any key to conTinue. # 可能该line不存在

其实在配置模板的时候已经添加了配置，但是更新后，启用了新的内核导致配置没有生效。编辑本文档只为存档记录。

一、删除更新系统后老内核kernel

• 1. 查看系统存在的内核

[root@centos6 ~]# rpm -qa | grep kernel
dracut-kernel-004-409.el6_8.2.noarch
kernel-firmware-2.6.32-642.4.2.el6.noarch
kernel-2.6.32-642.4.2.el6.x86_64
kernel-2.6.32-431.el6.x86_64

• 2. 确认系统已经使用最新的内核启动

[root@centos6 ~]# uname -a
Linux centos6 2.6.32-642.4.2.el6.x86_64 #1 SMP Tue Aug 23 19:58:13 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

• 3. 删除旧内核，无需手动修改grub.conf文件

[root@centos6 ~]# yum remove kernel-2.6.32-431.el6.x86_64

其他blog上写到remove kernel-devel 但是CentOS6.5最小化安装环境已经没有安装该rpm包。

• 4. 查看grub.conf文件可以看到老的kernel在menu中也已经移除

[root@centos6 ~]# cat /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/vg_linux-lv_root
# initrd /initrd-[generic-]version.img
#boot=/dev/vda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.32-642.4.2.el6.x86_64)
        root (hd0,0)
        kernel /vmlinuz-2.6.32-642.4.2.el6.x86_64 ro root=/dev/mapper/vg_linux-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_LVM_LV=vg_linux/lv_swap rd_NO_MD rd_LVM_LV=vg_linux/lv_root SYSFONT=latarcyrheb-sun16 crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
        initrd /initramfs-2.6.32-642.4.2.el6.x86_64.img

二、配置虚拟机模板支持vish console功能

• 1. 添加ttyS0的安全许可

# 添加ttyS0的许可，允许root登陆
[root@centos6 ~]# echo "ttyS0" >> /etc/securetty

• 2. 编辑/etc/inittab，添加如下

[root@centos6 ~]# cat /etc/inittab
... ...
S0:12345:respawn:/sbin/agetty ttyS0 115200,1152000 xterm

• 3. 配置grub.conf
  在kernel行添加如下配置console=tty0 console=ttyS0,115200n8

[root@centos6 ~]# cat /etc/grub.conf 
... ... #省略
default=0
timeout=5
splashimage=(hd0,0)
        kernel /vmlinuz-2.6.32-642.4.2.el6.x86_64 ro root=/dev/mapper/vg_linux-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_LVM_LV=vg_linux/lv_swap rd_NO_MD rd_LVM_LV=vg_linux/lv_root SYSFONT=latarcyrheb-sun16 crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet console=tty0 console=ttyS0,115200n8
        initrd /initramfs-2.6.32-642.4.2.el6.x86_64.img

• 4. 重启虚拟机

[root@centos6 ~]# reboot

• 5. 确认配置生效
  在KVM宿主机执行命令

[root@kvm01 ~]# virsh console instance001
virsh console instance001
Connected to domain instance001
Escape character is ^] #此处[Enter]

CentOS release 6.8 (Final)
Kernel 2.6.32-642.4.2.el6.x86_64 on an x86_64

centos6 login: root
@R_696_5747@d:  #此处输入root密码
Last login: Fri Sep  2 03:53:22 on ttyS0

三、参考文档

1. http://www.cnblogs.com/zrcoffee/archive/2012/10/31/2748056.html
2. http://www.linuxidc.com/Linux/2013-02/79556.htm