= Xen 於 OpenNEbual 的配置 =
== 1. 前提 ==
 * 已安裝 Xen 和 Xen Kernel
 * /etc/init.d/xend 可以正常執行
 * oneadmin 使用者可以執行 Xen 相關的指令
{{{
$ sudo vim /etc/sudoers
%xen    ALL=(ALL) NOPASSWD: /usr/sbin/xm *
%xen    ALL=(ALL) NOPASSWD: /usr/sbin/xentop *

$ sudo /opt/drb/sbin/drbl-cp-host /etc/sudoers /etc/sudoers
}}}

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== 2. Xen Driver 的檔案 ==
 * 主要有以下4個：  
   * $ONE_LOCATION/lib/mads/one_vmm_xen : Shell script wrapper to the driver itself. Sets the environment and other bootstrap tasks.
   * $ONE_LOCATION/lib/mads/one_vmm_xen.rb : The actual XEN driver.
   * $ONE_LOCATION/etc/vmm_xen/vmm_xenrc : environment setup and bootstrap instructions
   * $ONE_LOCATION/etc/vmm_xen/vmm_xen.conf : set here default values for XEN domain definitions.

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== 3.Xen Driver 的配置 ==
 * 告訴 ONE ，使用的 Hypervisior 是 Xen
{{{
$ sudo vim $ONE_LOCATION/etc/oned.conf
    IM_MAD = [
        name       = "im_xen",
        executable = "one_im_ssh",
        arguments  = "im_xen/im_xen.conf",
        default    = "im_xen/im_xen.conf" ]
	
    VM_MAD = [
        name       = "vmm_xen",
        executable = "one_vmm_xen",
        default    = "vmm_xen/vmm_xen.conf",
        type       = "xen" ]
}}}
   * 上面設定檔的 IM 是 Information Manager，VM 是 Virtualization Managers
     * name：driver 名稱，當加入 host 時會使用到
     * executable：driver 的執行檔 (位於 $ONE_LOCATION/lib/mads)
     * default：driver 的設定檔 (位於 $ONE_LOCATION/etc)
     * type：視為 xen 的 driver
  * default file ($ONE_LOCATION/etc/vmm_xen/vmm_xen.conf)，所有 domU 預設都會使用這些 attribute，也可視為 Template
     * CPU=0.6
     * CERDIT
     * 附加的屬性： RAW = [ type="xen", data="on_crash=destroy" ]
     * 範例檔
{{{
CPU      = 1
MEMORY   = 128
OS       = [kernel="/path-to-kernel",initrd= "/path-to-initrd",root="sda1" ]
DISK     = [source="/path-to-image-file",target="sda",readonly="no"]
NIC      = [mac="xx.xx.xx.xx.xx.xx", bridg="eth0"]
GRAPHICS = [type="vnc",listen="127.0.0.1",port="5900"]
}}}
  * Run command file ($ONE_LOCATION/etc/vmm_xen/vmm_xenrc)，包含了一些 Xen 指令路徑 (xm, xentop)