XEN--虚拟服务器无法上网解决案例
分析：
实体机器10.0.0.229，eth0和eth1 。eth1和交换机连接，eth0 未用
/sbin/ifconfig
eth1 Link encap:Ethernet HWaddr 00:1E:90:6A:A0:F9
inet addr:10.0.0.229 Bcast:10.0.0.255 Mask:255.255.255.0
inet6 addr: fe80::21e:90ff:fe6a:a0f9/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:335948116 errors:0 dropped:328633 overruns:0 frame:0
TX packets:730400280 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:27731724580 (25.8 GiB) TX bytes:1077307892050 (1003.3 GiB)
Memory:fd8c0000-fd8e0000
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:16436 Metric:1
RX packets:63577 errors:0 dropped:0 overruns:0 frame:0
TX packets:63577 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:117854954 (112.3 MiB) TX bytes:117854954 (112.3 MiB)
peth1 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:9 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:1494 (1.4 KiB)
vif4.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:47873 errors:0 dropped:0 overruns:0 frame:0
TX packets:743612 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:32
RX bytes:1341108 (1.2 MiB) TX bytes:31259471 (29.8 MiB)
vif5.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:739556 errors:0 dropped:0 overruns:0 frame:0
TX packets:47547 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:32
RX bytes:20734610 (19.7 MiB) TX bytes:1996974 (1.9 MiB)
xenbr1 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:836254 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:23462121 (22.3 MiB) TX bytes:0 (0.0 b)
/etc/init.d/xend status #查看当前运行的虚拟服务器
xend is running
xm list
Name ID Mem(MiB) VCPUs State Time(s)
Domain-0 0 4096 8 r----- 173001.1
arch01 4 6143 4 -b---- 1620.9
nagios 5 2047 1 -b---- 3234.1
/etc/xen/scripts/network-bridge status #检查虚拟网卡连接状态
============================================================
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 100
link/ether 00:1e:90:6a:a0:f9 brd ff:ff:ff:ff:ff:ff
inet 10.0.0.229/24 brd 10.0.0.255 scope global eth1
inet6 fe80::21e:90ff:fe6a:a0f9/64 scope link
valid_lft forever preferred_lft forever
13: xenbr1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
bridge name bridge id STP enabled interfaces
xenbr1 8000.feffffffffff no vif5.0
vif4.0
10.0.0.0/24 dev eth1 proto kernel scope link src 10.0.0.229
169.254.0.0/16 dev eth1 scope link
default via 10.0.0.248 dev eth1
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1
0.0.0.0 10.0.0.248 0.0.0.0 UG 0 0 0 eth1
或者用命令：brctl
[root@bigtest ~]# brctl show
bridge name bridge id STP enabled interfaces
xenbr1 8000.feffffffffff no vif5.0
vif4.0
找一正常的对比：
[root@bigWLWX019 ~]# brctl show
bridge name bridge id STP enabled interfaces
virbr0 8000.000000000000 yes #这一条可忽略，因为我们采用的是桥接
xenbr0 8000.feffffffffff no peth0
vif0.
==============================================================================
/etc/xen/目录xend-config.sxp配置文件：
# Your default ethernet device is used as the outgoing interface, by default.
# To use a different one (e.g. eth1) use
#
# (network-script 'network-bridge netdev=eth1') #默认的
#
# The bridge is named xenbr0, by default. To rename the bridge, use
#
# (network-script 'network-bridge bridge=<name>') #默认的
解决办法：
步骤一、当前和交换机相连的是eth1，所以我们需要将xend-config.sxp文件做相应改动，如下：
xend-config.sxp
# Your default ethernet device is used as the outgoing interface, by default.
# To use a different one (e.g. eth1) use
##-------2011-06-13-----------------------------#
(network-script 'network-bridge netdev=eth1') #去掉前面的注释符，
#
# The bridge is named xenbr0, by default. To rename the bridge, use
#
#-------2011-06-15------------------------------#
(network-script 'network-bridge bridge=xenbr1') #去掉前面的注释符，将桥接设备改为xenbr1.
#
步骤二、重新载入配置文件
/etc/init.d/xend reload
参照原理图
测试虚拟服务器的上网情况，结果令人失望，还是不行，检查虚拟网卡情况如下：
[root@bigtest ~]# brctl show
bridge name bridge id STP enabled interfaces
xenbr1 8000.feffffffffff no vif5.0 #缺少peth1
vif4.0
既然其中的原因已找到，通讯原理也搞清楚了，接下来我们需要做的事就是，重新启动
实体机（我先在本本的虚拟机上搞的测试，验证了结果），加载peth1.
周知10.0.0.229服务器业务相关负责人，说明情况，需要重新启动机器，确认OK，重新启动机器，检查：
[root@bigtest ~]# brctl show
bridge name bridge id STP enabled interfaces
xenbr1 8000.feffffffffff no vif2.0
peth1 #peth1已出现
vif0.1
在实体机上ping 虚拟服务器10.0.0.101，进行测试：ping 10.0.0.101 ，OK。
登录虚拟服务器，ping 外网IP，OK。
至此上网问题解决OK。