虚拟化技术基础原理

程序局限性原因：
空间局限性
时间局限性

IO设备的部分：
设备控制器和设备本身
控制器：集成在主板上的一块芯片或一组芯片
驱动程序：通常应该由设备生产商：位于内核中
每个控制器都有少量的用于通信的寄存器，每个寄存器表现为一个I/O端口；
所有的寄存器组合成为设备的IO地址空间；

    实现输入、输出：
        三种方式：
                1、轮询：忙等待
                    2、中断：
                内核处理中断分为两步：
                                中断上半部、中断的下半部
                    3、DMA：

    OS：
        cpu：时间片，time slice
            memory：虚拟地址空间
            I/O：文件
            进程
                资源集
                        cpu事件
                            memory：抽象，虚拟地址空间（32bits：4G）
                            I/O：打开的多个文件，fd（file descriptor）
                                正常文件
                                    设备文件
                                    管道文件

            进程：task                         

cpu虚拟化：
    模拟：emulation
        虚拟：virtulization
            完全虚拟化（full-virtulization）
                    BT：二进制翻译（软件）
                        HVM：硬件辅助的虚拟化（硬件）
                半虚拟化：

Memory：
    进程：现行地址空间
        内核：物理地址空间

        MMU Virtulization
            Inter：EPT，Extended Page Table
            AMD：NTP，Nested Page Table

        TLB virtulization
            tagged TLB

I/O：
    外存：
            硬盘、光盘、U盘
        网络设备：
        网卡
        显示设备：
            VGA：frame buffer机制
        键盘鼠标：
      ps/2，usb

        I/O虚拟化的方式：
            模拟：完全使用软件来模拟真实硬件
                半虚拟化：
                IO-through：IO透传

        Inter：VT-d
            基于北桥的硬件辅助的虚拟化技术：

两种实现方式：
    Type-I：
            xen，vmware ESX/ESXi
        Type-II：
            kvm，vmware，workstation，virtualbox

Inter硬件辅助的虚拟化：
CPU：vt-x，EPT，tagged-TLB
IO/CPU：vt-d，IOV，VMDq

    第一类：跟处理器相关：vt-x
    第二类：跟芯片相关：vt-d
    第三类：跟IO相关：VMDq和SR-IOV

QEMU，virtio

虚拟化技术的分类
模拟：著名的模拟器，PearPC，Bochs，QEMU
完全虚拟化：也称为native virtulization
两种加速方式：
BT
HVM
VMware Workstation，VMware Server，Parallels Desktop，KVM，Xen（HVM）

    半虚拟化：para-virtualization     
             xen，uml（user-mod linux）
    OS级别的虚拟化：
        OpenVZ，lxc
          Solaris Contaniners
            FreeBSD jails
    库虚拟化：
        wine，
    应用程序虚拟化：
        jvm

虚拟化网络：
nat mode
bridge mode
routed mode
isolation mode

使用brctl的配置过程：

    # brctl add br0
        # brctl stp br0 on
        # ifconfig eth0 0 up
        # brctl addif br0 eth0
        # ifconfig br0 IP/NETMASK up
        # route add default gw GW       

TUN与TAP
在计算机网络中，TUN与TAP是操作系统内核中的虚拟网络设备，不同于普通靠硬件网络办卡实现的设备，这些虚拟的网络设备全部用软件实现，并向运行于操作系统上的软件提供与硬件的网络设备完全相同的功能；

TAP等同于一个以太网设备，它操作第二层数据包如以太网数据帧，TUN模拟了网络层设备，操作第三层数据包如IP数据包。

操作系统通过TUN/TAP设备向绑定该设备的用户空间的程序发送数据，反之，用户空间的程序也可以像操作硬件的网络设备那样，通过TUN/TAP设备发送数据，在后种情况下，TUN/TAP设备向操作系统的网络栈投递（或"注入"）数据包，从而模拟从外部接受数据的过程。

[root@node1 ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0C:29:11:21:56
          inet addr:192.168.10.6  Bcast:192.168.10.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe11:2156/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:141 errors:0 dropped:0 overruns:0 frame:0
          TX packets:74 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:14934 (14.5 KiB)  TX bytes:9717 (9.4 KiB)

eth1      Link encap:Ethernet  HWaddr 00:0C:29:11:21:60
          inet addr:192.168.190.128  Bcast:192.168.190.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe11:2160/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:193 errors:0 dropped:0 overruns:0 frame:0
          TX packets:30 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:16345 (15.9 KiB)  TX bytes:3153 (3.0 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

桥不支持NetworkManger管理，需要关闭NetworkManger启动
[root@node1 ~]# chkconfig --list NetworkManager

桥使用network管理

[root@node1 ~]# chkconfig --list network
network         0:关闭  1:关闭  2:启用  3:启用  4:启用  5:启用  6:关闭

[root@node1 ~]# yum -y install bridge-utils

[root@node1 ~]# rpm -ql bridge-utils
/usr/sbin/brctl
/usr/share/doc/bridge-utils-1.2
/usr/share/doc/bridge-utils-1.2/AUTHORS
/usr/share/doc/bridge-utils-1.2/COPYING
/usr/share/doc/bridge-utils-1.2/FAQ
/usr/share/doc/bridge-utils-1.2/HOWTO
/usr/share/man/man8/brctl.8.gz

[root@node1 ~]# cd /etc/sysconfig/network-scripts/
[root@node1 network-scripts]# cp ifcfg-eth0 ifcfg-br0

关闭NetworkManger服务进行管理：NM_CONTROLLED=no

[root@node1 network-scripts]# vim ifcfg-br0
DEVICE=br0
TYPE=Bridge
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
IPADDR=192.168.10.6
NETMASK=255.255.255.0

[root@node1 network-scripts]# vim ifcfg-eth0
DEVICE=eth0
HWADDR=00:0C:29:11:21:56
TYPE=Ethernet
UUID=f343369c-4aa9-4975-81b3-3f38f4c56ef0
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
BRIDGE=br0

[root@node1 network-scripts]# service network restart
正在关闭接口 eth0： bridge br0 does not exist!
                                                           [确定]
正在关闭接口 eth1：                                        [确定]
关闭环回接口：                                             [确定]
弹出环回接口：                                             [确定]
弹出界面 eth0：                                            [确定]
弹出界面 eth1：
正在决定 eth1 的 IP 信息...完成。
                                                           [确定]
弹出界面 br0： Determining if ip address 192.168.10.6 is already in use for device br0...
                                                           [确定]

[root@node1 network-scripts]# ifconfig
br0       Link encap:Ethernet  HWaddr 00:0C:29:11:21:56
          inet addr:192.168.10.6  Bcast:192.168.10.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe11:2156/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:21 errors:0 dropped:0 overruns:0 frame:0
          TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:2174 (2.1 KiB)  TX bytes:2264 (2.2 KiB)

eth0      Link encap:Ethernet  HWaddr 00:0C:29:11:21:56
          inet6 addr: fe80::20c:29ff:fe11:2156/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1353 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1217 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:105072 (102.6 KiB)  TX bytes:120035 (117.2 KiB)

eth1      Link encap:Ethernet  HWaddr 00:0C:29:11:21:60
          inet addr:192.168.190.128  Bcast:192.168.190.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe11:2160/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:19201 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8181 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:27802761 (26.5 MiB)  TX bytes:449250 (438.7 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

[root@node1 network-scripts]# brctl show
bridge name     bridge id               STP enabled     interfaces
br0             8000.000c29112156       no              eth0

[root@node1 network-scripts]# brctl --help
Usage: brctl [commands]
commands:
        addbr                           add bridge
        delbr                           delete bridge
        addif                   add interface to bridge
        delif                   delete interface from bridge
        setageing                 set ageing time
        setbridgeprio             set bridge priority
        setfd                     set bridge forward delay
        sethello                  set hello time
        setmaxage                 set max message age
        sethashel                  set hash elasticity
        sethashmax                 set hash max
        setmclmc                   set multicast last member count
        setmcrouter                set multicast router
        setmcsnoop                 set multicast snooping
        setmcsqc                   set multicast startup query count
        setmclmi                  set multicast last member interval
        setmcmi                   set multicast membership interval
        setmcqpi                  set multicast querier interval
        setmcqi                   set multicast query interval
        setmcqri                  set multicast query response interval
        setmcqri                  set multicast startup query interval
        setpathcost         set path cost
        setportprio         set port priority
        setportmcrouter      set port multicast router
        show            [  ]            show a list of bridges
        showmacs                        show a list of mac addrs
        showstp                         show bridge stp info
        stp              {on|off}       turn stp on/off

[root@node1 network-scripts]# brctl stp br0 on
[root@node1 network-scripts]# brctl show
bridge name     bridge id               STP enabled     interfaces
br0             8000.000c29112156       yes             eth0

命令创建桥：

[root@node2 ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0C:29:E8:20:12
          inet addr:192.168.10.7  Bcast:192.168.10.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fee8:2012/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:27 errors:0 dropped:0 overruns:0 frame:0
          TX packets:40 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:4781 (4.6 KiB)  TX bytes:5365 (5.2 KiB)

eth1      Link encap:Ethernet  HWaddr 00:0C:29:E8:20:1C
          inet addr:192.168.190.129  Bcast:192.168.190.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fee8:201c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:40 errors:0 dropped:0 overruns:0 frame:0
          TX packets:15 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3072 (3.0 KiB)  TX bytes:1511 (1.4 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

[root@node2 ~]# chkconfig --list NetworkManager
[root@node2 ~]# chkconfig --list network
network         0:关闭  1:关闭  2:启用  3:启用  4:启用  5:启用  6:关闭
[root@node2 ~]# yum -y install bridge-utils

[root@node2 ~]# brctl --help
Usage: brctl [commands]
commands:
        addbr                           add bridge
        delbr                           delete bridge
        addif                   add interface to bridge
        delif                   delete interface from bridge
        setageing                 set ageing time
        setbridgeprio             set bridge priority
        setfd                     set bridge forward delay
        sethello                  set hello time
        setmaxage                 set max message age
        sethashel                  set hash elasticity
        sethashmax                 set hash max
        setmclmc                   set multicast last member count
        setmcrouter                set multicast router
        setmcsnoop                 set multicast snooping
        setmcsqc                   set multicast startup query count
        setmclmi                  set multicast last member interval
        setmcmi                   set multicast membership interval
        setmcqpi                  set multicast querier interval
        setmcqi                   set multicast query interval
        setmcqri                  set multicast query response interval
        setmcqri                  set multicast startup query interval
        setpathcost         set path cost
        setportprio         set port priority
        setportmcrouter      set port multicast router
        show            [  ]            show a list of bridges
        showmacs                        show a list of mac addrs
        showstp                         show bridge stp info
        stp              {on|off}       turn stp on/off

[root@node2 ~]# brctl show
bridge name     bridge id               STP enabled     interfaces
[root@node2 ~]# brctl addbr br0

[root@node2 ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0C:29:E8:20:12
          inet addr:192.168.10.7  Bcast:192.168.10.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fee8:2012/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:557 errors:0 dropped:0 overruns:0 frame:0
          TX packets:385 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:48970 (47.8 KiB)  TX bytes:39748 (38.8 KiB)

eth1      Link encap:Ethernet  HWaddr 00:0C:29:E8:20:1C
          inet addr:192.168.190.129  Bcast:192.168.190.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fee8:201c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5053 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2694 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:7236029 (6.9 MiB)  TX bytes:148485 (145.0 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:2 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:200 (200.0 b)  TX bytes:200 (200.0 b)

[root@node2 ~]# ifconfig eth0 0 up

[root@node2 ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0C:29:E8:20:12
          inet6 addr: fe80::20c:29ff:fee8:2012/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:600 errors:0 dropped:0 overruns:0 frame:0
          TX packets:404 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:52372 (51.1 KiB)  TX bytes:41802 (40.8 KiB)

eth1      Link encap:Ethernet  HWaddr 00:0C:29:E8:20:1C
          inet addr:192.168.190.129  Bcast:192.168.190.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fee8:201c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5118 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2749 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:7247051 (6.9 MiB)  TX bytes:156881 (153.2 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:2 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:200 (200.0 b)  TX bytes:200 (200.0 b)

[root@node2 ~]# brctl addif br0 eth0
[root@node2 ~]# ifconfig br0 192.168.10.7/24 up
[root@node2 ~]# route add default gw 192.168.10.254

[root@node2 ~]# ifconfig
br0       Link encap:Ethernet  HWaddr 00:0C:29:E8:20:12
          inet addr:192.168.10.7  Bcast:192.168.10.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fee8:2012/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:24 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1104 (1.0 KiB)  TX bytes:468 (468.0 b)

eth0      Link encap:Ethernet  HWaddr 00:0C:29:E8:20:12
          inet6 addr: fe80::20c:29ff:fee8:2012/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:632 errors:0 dropped:0 overruns:0 frame:0
          TX packets:410 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:54292 (53.0 KiB)  TX bytes:42270 (41.2 KiB)

eth1      Link encap:Ethernet  HWaddr 00:0C:29:E8:20:1C
          inet addr:192.168.190.129  Bcast:192.168.190.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fee8:201c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5331 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2881 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:7263087 (6.9 MiB)  TX bytes:168737 (164.7 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:2 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:200 (200.0 b)  TX bytes:200 (200.0 b)