RHEL6.3克隆虛擬機後的網卡啓動失敗問題解析公司測試環境安裝的都是RHEL6.3，在進行虛擬機克隆後，發現clone的虛擬機網卡起不來，具體報如下錯誤：
[root@localhost Desktop]# service network restart
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Error: No suitable device found: no device found for connection 'System eth0'.
[FAILED]
當你執行ifconfig命令的時候，會發現顯示eth1網卡的配置文件卻爲/etc/sysconfig/network-scripts/ifcfg-eth0。
[root@localhost network-scripts]# ifconfig|grep addr
eth1 Link encap:Ethernet HWaddr 00:0c:29:f4:95:e3
inet6 addr: fe80::20c:29ff:fe5c:65b7/64 Scope:Link
Interrupt:19 Base address:0x2024
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
[root@localhost network-scripts]# ls
ifcfg-eth0 ifdown-isdn ifup-aliases ifup-plusb init.ipv6-global
ifcfg-lo ifdown-post ifup-bnep ifup-post net.hotplug
ifdown ifdown-ppp ifup-eth ifup-ppp network-functions
ifdown-bnep ifdown-routes ifup-ippp ifup-routes network-functions-ipv6
ifdown-eth ifdown-sit ifup-ipv6 ifup-sit
ifdown-ippp ifdown-tunnel ifup-isdn ifup-tunnel
ifdown-ipv6 ifup ifup-plip ifup-wireless
[root@localhost network-scripts]#
產生這個問題的原因是虛擬機分配給操作系統的虛擬網卡MAC地址是不一樣的。第一個系統的網卡MAC地址記錄在了/etc/udev/rules.d/70-persistent-net.rules，命名爲eth0。新克隆分配的系統的網卡MAC地址也記錄在了該文件當中，與之前的系統一樣，因此有了衝突。
可以查看一下兩個機子的這個70-persistent-net.rules文件的內容
第一個系統：
[root@localhost rules.d]# cat 70-persistent-net.rules
# This file was automatically generated by the /lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.
# PCI device 0x1022:0x2000 (pcnet32)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:f4:95:e3", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
克隆後的系統：
[root@localhost rules.d]# cat 70-persistent-net.rules
# This file was automatically generated by the /lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.
# PCI device 0x1022:0x2000 (pcnet32)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:f4:95:e3", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"
我們可以看到這兩個系統中的MAC地址一樣。
問題解決方法：
刪除克隆後這個系統中的 /etc/udev/rules.d/70-persistent-net.rules文件，重啓後系統會重新生成一個新的虛擬網卡MAC地址，然後把這個文件裏NAME="eth1"的eth1改成eth0，同時也要修改ATTR{address}裏的mac地址和/etc/sysconfig/network-scripts/ifcfg-eth0文件mac地址，並與新的虛擬網卡MAC地址保持一致。
如:將原文件的
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:f4:95:e3", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"
改爲 SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:5c:65:b7", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
修改/etc/sysconfig/network-scripts/ifcfg-eth0文件
DEVICE="eth0"
IPV6INIT="yes"
NM_CONTROLLED="yes"
ONBOOT="yes"
TYPE="Ethernet"
UUID="05944003-ae77-4c9d-9e58-3ec2851db71d"
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
NAME="System eth0"
HWADDR=00:0c:29:5c:65:b7
然後重啓網絡服務，發現一切正常了。
[root@localhost Desktop]# service network restart
Shutting down interface eth0: Device state: 3 (disconnected)
[ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Active connection state: activating
Active connection path: /org/freedesktop/NetworkManager/ActiveConnection/1
state: activated
Connection activated [ OK ]
設置IP後，再檢查一下
[root@localhost Desktop]# ifconfig|grep addr
eth0 Link encap:Ethernet HWaddr 00:0C:29:5C:65:B7
inet addr:192.168.0.129 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe5c:65b7/64 Scope:Link
Interrupt:19 Base address:0x2024
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
注：如果你執行ifconfig命令的時候，發現仍然顯示eth1而不是eth0，可以將系統重啓一遍就變過來了。