OPS Notes By 枯木

CentOS6.4 X86_64 kvm+PXE备忘

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Install 安装

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# yum install qemu-kvm qemu-img 
# 使用kvm至少要安装的包，一个提供用户级别kvm模拟器，一个提供磁盘镜像的管理
# 安装虚拟化管理的相关工具
# yum install virt-manager libvirt \     
libvirt-python python-virtinst libvirt-client

也可以yum groupinstall虚拟化组件，具体可参考Redhat官方文档

  • KVM 管理工具
    • kvm 内核模块 <- qemu 管理工具 (可用性低)
    • qemu 是开源虚拟化软件, 虚拟不同 CPU 架构, 可以 x86 虚拟 power cpu
    • libvirt, virsh, virt-manager (redhat 的辅助工具)
    • libvirt api 提供管理接口工具
    • virt-manager 调用 libvirt 工具

  • ibvirt接口
    • virsh 命令行工具
    • virt-manager 图形工具
    • RHEV-M (redhat专用收费软件)

  • 支持三种虚拟设备
    • Emulated software devices 仿真设备 -> 南北桥, USB, PS/2 ISA PCI
    • Para-virtualized devices -> 时钟, 网络, 串口
    • Physically shared devices –> 光纤设备

安装完之后就可以启动kvm了

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# /etc/init.d/libvirtd start

桥接网络

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# yum install bridge-utils -y

桥接实例:

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# cat /etc/sysconfig/network-scripts/ifcfg-eth0 
DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
NAME="System eth0"
BRIDGE="br0"
# cat /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE="br0"
TYPE="Bridge"  # 注意大小写
BOOTPROTO="static"
IPADDR=192.168.80.131
NETMASK=255.255.255.0
GATEWAY=192.168.80.2
ONBOOT="yes"
DELAY=0

具体可参考: CentOS / Redhat: KVM Bridged Network Configuration

构建无人值守，实现KVM PXE安装

安装相关软件

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# yum install tftp-server syslinux dhcp vsftpd -y
dhcp

dhcp example:

dhcp 
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# cat /etc/dhcp/dhcpd.conf 
subnet 192.168.80.0 netmask 255.255.255.0 {
    range 192.168.80.10 192.168.80.100;
    default-lease-time 600;
    max-lease-time 7200;
    next-server 192.168.80.131; # PXE Server地址
    filename "pxelinux.0";      # 引导文件名
}
# /etc/init.d/dhcpd restart

tftp

tftp example:

tftp
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# cat /etc/xinetd.d/tftp 
service tftp
{
    socket_type     = dgram
    protocol        = udp
    wait            = yes
    user            = root
    server          = /usr/sbin/in.tftpd
    server_args     = -s /var/lib/tftpboot
    disable         = no # 默认yes，改为no即可
    per_source      = 11
    cps             = 100 2
    flags           = IPv4
}
# /etc/init.d/xinetd restart

vsftpd

新建/var/ftp/centos目录，把CentOS光盘镜像挂载至/var/ftp/centos下

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# mkdir /var/ftp/centos
# mount /dev/cdrom /var/ftp/centos # 挂载镜像使用-o loop
# /etc/init.d/vsftpd restart

无人值守

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# mkdir /var/lib/tftpboot/CentOS6
# cp /var/ftp/centos/images/pxeboot/{initrd.img,vmlinuz} /var/lib/tftpboot/CentOS6
# cp /var/ftp/centos/isolinux/{boot.msg,vesamenu.c32} /var/lib/tftpboot/
# cp /usr/share/syslinux/pxelinux.0 /var/lib/tftpboot/
# mkdir /var/ftp/tftpboot/pxelinux.cfg
# cp /var/ftp/centos/isolinux/isolinux.cfg /var/lib/tftpboot/pxelinux.cfg/default
tftpboot目录树结构
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# tree /var/lib/tftpboot/
/var/lib/tftpboot/
├── boot.msg
├── CentOS6
│   ├── initrd.img
│   └── vmlinuz
├── pxelinux.0
├── pxelinux.cfg
│   └── default
└── vesamenu.c32

2 directories, 6 files

pxelinux.cfg/default example:

pxe default
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# cat /var/lib/tftpboot/pxelinux.cfg/default                                                                                                                      
# default CentOS6_PXE # 默认启动'default CentOS6_PXE'标记的内核
default vesamenu.c32  # 菜单选项
timeout 100 # 单位是1/10s
# prompt 1  # 为 '0' 时则不提示'boot: '，将会直接启动 'default' 参数中指定的内容

display boot.msg    # 启动时显示

# menu background splash.jpg    # 菜单背景等
menu title Welcome to CentOS 6.4!
menu color border 0 #ffffffff #00000000
menu color sel 7 #ffffffff #ff000000
menu color title 0 #ffffffff #00000000
menu color tabmsg 0 #ffffffff #00000000
menu color unsel 0 #ffffffff #00000000
menu color hotsel 0 #ff000000 #ffffffff
menu color hotkey 7 #ffffffff #ff000000
menu color scrollbar 0 #ffffffff #00000000

label CentOS6_PXE
  menu label ^PXE Install CentOS KVM
  kernel /CentOS6/vmlinuz
  append ks=ftp://192.168.80.131/ks.cfg initrd=/CentOS6/initrd.img
label rescue
  menu label ^Rescue installed system
  kernel /CentOS6/vmlinuz
  append initrd=/CentOS6/initrd.img rescue

关于PXE的进一步细节可以参考pxelinux官方文档

ks.cfg example:

ks.cfg
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# cat /var/ftp/ks.cfg
# System authorization information
auth  --useshadow  --enablemd5
# System bootloader configuration
bootloader --location=mbr
# Clear the Master Boot Record
zerombr
# Partition clearing information
clearpart --all --initlabel
# Use text mode install
text
# Firewall configuration
firewall --disabled
skipx
# Run the Setup Agent on first boot
firstboot --disable
# System keyboard
keyboard us
# System language
lang en_US
# Installation logging level
logging --level=info
# Use network installation
url --url=ftp://192.168.80.131/centos
# Network information
network --bootproto=dhcp --device=eth0 --onboot=on
# Reboot after installation
reboot
#Root password
rootpw --iscrypted $1$duSkJ1$1P5qGnqUGn3S1MTTFiPJY.

# SELinux configuration
selinux --disabled
# System timezone
timezone  Asia/Shanghai
# Install OS instead of upgrade
install

# Disk partitioning information
part /boot --asprimary --bytes-per-inode=4096 --fstype="ext3" --size=100
part / --bytes-per-inode=4096 --fstype="ext3" --size=5000
part swap --bytes-per-inode=4096 --fstype="swap" --size=512

%packages --nobase
@core
@Development tools
acpid   # 如果不安装acpid服务，virsh shutdown virtual_name 命令会失效
vim
wget
lsof
%end

如果最小化安装则软件包选择如下：

Minimal install
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%packages --nobase
@core

关于kickstart的更进一步了解可参考红帽官档Kickstart Options Installing guest virtual machines with PXE

PXE 安装KVM虚拟机

如果要开启–graphics vnc选项，则需要修改vnc监听端口，默认监听的是127.0.0.1，修改为0.0.0.0即可

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# grep '^vnc_listen' /etc/libvirt/qemu.conf
vnc_listen = "0.0.0.0"
# /etc/init.d/libvirtd restart

man手册关于vnc端口介绍摘录：

Address to listen on for VNC/Spice connections. Default is typically 127.0.0.1   
(localhost only), but some hypervisors allow changing this globally     
(for example, the qemu driver default can be changed   in /etc/libvirt/qemu.conf).   
Use 0.0.0.0 to allow access from other machines. This is use by ’vnc’ and ’spice.

安装实例：

通过location方式结合Kickstart安装
  • –extra-args指定ks相关选项，并且指定console类型使得virsh console可以连接操作，也可指定客户机IP、网关、DNS等，无需DHCP：
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# virt-install --name centos --ram=1024 --vcpus=1 --os-type=linux --os-variant=rhel6 \
--network bridge:br0 --disk path=/var/lib/libvirt/images/centos6-machine1.img,size=10 \
--location ftp://192.168.80.131/centos/ --extra-args "ks=ftp://192.168.80.131/ks.cfg \
ksdevice=eth0 ip=192.168.80.150  netmask=255.255.255.0 console=ttyS0"
PXE方式安装
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# virt-install --connect qemu:///system --network=bridge:br0 \
--pxe --name rhel6-machine1 --ram=1024 --vcpus=1 \
--os-type=linux --os-variant=rhel6 --disk \
path=/var/lib/libvirt/images/rhel6-machine1.img,size=10

注意: 如果需要指定console，–pxe是不支持–extra-args额外选项的，所以需要在pxe default 文件添加相关内容[SERIAL和console]，如下example

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SERIAL 0 115200
label CentOS6_PXE
    menu label ^PXE Install CentOS KVM
    kernel /CentOS6/vmlinuz
    append ks=ftp://192.168.80.131/ks.cfg initrd=/CentOS6/initrd.img console=tty0 console=ttyS0,115200
本地安装：
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# virt-install --name centos --ram=1024 --vcpus=1 --os-type=linux \
--os-variant=rhel6 --location /mnt/ --network bridge:br0 \
--disk path=/var/lib/libvirt/images/rhel6.img,size=10 --extra-args "console=ttyS0"

关于KVM的Guest安装方式，virt-install man手册中也有很多实例，这里不一一介绍。

开启–graphics vnc选项可在Windows下下载vncviewer客户端，输入对应IP和端口即可[ 笔者个人还是习惯通过console连接安装，不开启vnc选项 ]，如下

查看对应端口
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# netstat -tulnp | grep kvm
tcp        0      0 0.0.0.0:5900                0.0.0.0:*                   LISTEN      55762/qemu-kvm
tcp        0      0 0.0.0.0:5901                0.0.0.0:*                   LISTEN      56656/qemu-kvm

连接对应端口

连接之后,就可以正常安装了

virsh 操作命令

这里只介绍一些常用的virsh使用方法，具体的命令可以参看virsh的man手册介绍或者参考红帽官方文档Managing guests with virsh

默认只输入virsh命令会进入virsh的终端：如下，help可以获取命令帮助

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# virsh 
Welcome to virsh, the virtualization interactive terminal.

Type:  'help' for help with commands
       'quit' to quit

virsh #

virsh简单操作

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virsh # list    # 显示运行或者暂停的Guest
 Id    Name                           State
----------------------------------------------------
 28    centos6_1                      running

virsh # list --all  # 显示所有的Guest，包括状态为shut off的
 Id    Name                           State
----------------------------------------------------
 28    centos6_1                      running
 -     centos                         shut off

virsh # console centos6_1   # console方式连接Guest
Connected to domain centos6_1
Escape character is ^]      # 使用Ctrl+]即可退出

CentOS release 6.4 (Final)
Kernel 2.6.32-358.el6.x86_64 on an x86_64

localhost.localdomain login:
virsh # start centos        # 开启某个Guest
Domain centos started

virsh # list
 Id    Name                           State
----------------------------------------------------
 28    centos6_1                      running
 32    centos                         running
virsh # shutdown centos     
# 关闭某个Guest，这里一定要注意，如果Guest没有安装运行acpid服务，
# 则此方式失效，可以kill强制关闭，或者console/ssh连接执行关闭                                                                                                                       
Domain centos is being shutdown

删除某个Guest，一般需要两步走，对于正在运行的Guest则需要先关闭再继续两步走[也可以直接virsh destroy virtual_name], 这里就演示三步：

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virsh destroy guest_name
virsh undefine guest_name
rm -rf guest_img  # 删除虚拟存储

挂起主机

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virsh # list
 Id    Name                           State
----------------------------------------------------
 28    centos6_1                      running

virsh # suspend centos6_1   # 挂起主机
Domain centos6_1 suspended

virsh # list
 Id    Name                           State
----------------------------------------------------
 28    centos6_1                      paused


virsh # resume centos6_1    # 把主机从挂起状态切换至运行状态
Domain centos6_1 resumed

virsh # list
 Id    Name                           State
----------------------------------------------------
 28    centos6_1                      running

virsh #

virt-clone 克隆Guest

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# virt-clone --connect=qemu:///system --original=centos6_1 \
--name=centos6_2 -f /var/lib/libvirt/images/centos6_2.img
ERROR    Domain with devices to clone must be paused or shutoff.
# virsh suspend centos6_1
Domain centos6_1 suspended

# virsh list
 Id    Name                           State
----------------------------------------------------
 28    centos6_1                      paused

# virt-clone --connect=qemu:///system --original=centos6_1 \
--name=centos6_2 -f /var/lib/libvirt/images/centos6_2.img
Allocating 'centos6_2.img'           1% [-              ] 9.0 MB/s | 112 MB     18:44 ETA

参考和拓展资料

自己之前的两篇挫文： KVM在线迁移(动态迁移) RHEL6 KVM安装备忘

–EOF–

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