RHEL6.3克隆虚拟机后的网卡启动失败问题解析

公司测试环境安装的都是RHEL6.3，在进行虚拟机克隆后，发现clone的虚拟机网卡起不来，具体报如下错误：
[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]

当你执行ifconfig命令的时候，会发现显示eth1网卡的配置文件却为/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]#

产生这个问题的原因是虚拟机分配给操作系统的虚拟网卡MAC地址是不一样的。第一个系统的网卡MAC地址记录在了/etc/udev/rules.d/70-persistent-net.rules，命名为eth0。新克隆分配的系统的网卡MAC地址也记录在了该文件当中，与之前的系统一样，因此有了冲突。

可以查看一下两个机子的这个70-persistent-net.rules文件的内容

第一个系统：
[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"
 

克隆后的系统：

[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"
 

我们可以看到这两个系统中的MAC地址一样。

问题解决方法：
删除克隆后这个系统中的 /etc/udev/rules.d/70-persistent-net.rules文件，重启后系统会重新生成一个新的虚拟网卡MAC地址，然后把这个文件里NAME="eth1"的eth1改成eth0，同时也要修改ATTR{address}里的mac地址和/etc/sysconfig/network-scripts/ifcfg-eth0文件mac地址，并与新的虚拟网卡MAC地址保持一致。

如:将原文件的
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:f4:95:e3", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"
 

改为 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
然后重启网络服务，发现一切正常了。
[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  ]

设置IP后，再检查一下
[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：如果你执行ifconfig命令的时候，发现仍然显示eth1而不是eth0，可以将系统重启一遍就变过来了。