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18.17. 筆記型電腦設定
The task of configuring your RHEL 5.1 loaded laptop for use on a network environment, presents a number of potential challenges. Most WiFi and wired connections switch constantly during any given day, and Red Hat Virtualization assumes it has access to the same interface consistently. This results in the system performing ifup/ifdown calls to the network interface in use by Red Hat Virtualization. WiFi cards are not the ideal network connection method since Red Hat Virtualization uses the default network interface.
The idea here is to create a 'dummy' network interface for Red Hat Virtualization to use.
This technique allows you to use a hidden IP address space for your guests and Virtual Machines. To do this operation successfully, you must use static IP addresses as DHCP does not listen for IP addresses on the dummy network. You also must configure NAT/IP masquerading to enable network access for your guests and Virtual Machines. You should attach a static IP when you create the 'dummy' network interface.
在這個範例中,所使用的介面為 dummy0 而所使用的 IP 為 10.1.1.1。這個 script 稱為
ifcfg-dummy0
並位於 /etc/sysconfig/network-scripts/
目錄中:
DEVICE =dummy0 BOOTPROTO=none ONBOOT=yes USERCTL=no IPV6INIT=no PEERDNS=yes TYPE=Ethernet NETMASK=255.255.255.0 IPADDR=10.1.1.1 ARP=yes
您應該將
xenbr0
併到 dummy0
讓網路連接,即使從實體網路斷開。
You will need to make additional modifications to the
xend-config.sxp
file. You must locate the ( network-script 'network-bridge' bridge=xenbr0
) section and add include this in the end of the line:
netdev=dummy0
You must also make some modifications to your guest's domU networking configuration to enable the default gateway to point to dummy0. You must edit the DomU 'network' file that resides in the
/etc/sysconfig/
directory to reflect the example below:
NETWORKING=yes HOSTNAME=localhost.localdomain GATEWAY=10.1.1.1 IPADDR=10.1.1.10 NETMASK=255.255.255.0
建議啟動 NAT 於網域0中,因此 domU 能夠存取公共網路。如此,即使是無線網路的使用者也可解決 Red Hat 虛擬化無線網路的限制。您必須修改位於
/etc/rc3.d
目錄中的 S99XenLaptopNAT
檔案如下列範例:
#!/bin/bash # # XenLaptopNAT Startup script for Xen on Laptops # # chkconfig: - 99 01 # description: Start NAT for Xen Laptops # # PATH=/usr/bin:/sbin:/bin:/usr/sbin # export PATH GATEWAYDEV=`ip route | grep default | awk {'print $5'}` iptables -F case "$1" in start) if test -z "$GATEWAYDEV"; then echo "No gateway device found" else echo "Masquerading using $GATEWAYDEV" /sbin/iptables -t nat -A POSTROUTING -o $GATEWAYDEV -j MASQUERADE fi echo "Enabling IP forwarding" echo 1 > /proc/sys/net/ipv4/ip_forward echo "IP forwarding set to `cat /proc/sys/net/ipv4/ip_forward`" echo "done." ;; *) echo "Usage: $0 {start|restart|status}" ;; esac
如果您希望網路能夠於開機時自動設定,您必須建立一個軟式連結(softlink)至
/etc/rc3.d/S99XenLaptopNAT
。
當修改
modprobe.conf
檔案時,您必須加入下列命令列
alias dummy0 dummy options dummy numdummies=1