Centos
qemu-kvm/virsh：使用橋接網路時沒有網路連接
我在通過 libvirt/qemu-kvm 執行虛擬化時遇到問題，其中我的橋接網路設置似乎無法正常工作。我已經按照我能找到的每一個教程，並在論壇上花費了數小時和數小時，但目前無濟於事。
主機和訪客都在使用 Centos6。
這是主機的設置：
[root@node2 ~]# ifconfig -a bridge0 Link encap:Ethernet HWaddr BC:30:5B:E8:C0:4F inet addr:10.59.190.253 Bcast:10.59.190.255 Mask:255.255.255.0 inet6 addr: fe80::be30:5bff:fee8:c04f/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:5315 errors:0 dropped:0 overruns:0 frame:0 TX packets:3350 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:316961 (309.5 KiB) TX bytes:3943630 (3.7 MiB) eth0 Link encap:Ethernet HWaddr BC:30:5B:E8:C0:4F inet6 addr: fe80::be30:5bff:fee8:c04f/64 Scope:Link UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1 RX packets:5286 errors:0 dropped:0 overruns:0 frame:0 TX packets:5325 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:409939 (400.3 KiB) TX bytes:4095006 (3.9 MiB) Interrupt:16 Memory:c0000000-c0012800 eth1 Link encap:Ethernet HWaddr BC:30:5B:E8:C0:50 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) Interrupt:17 Memory:c2000000-c2012800 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:28 errors:0 dropped:0 overruns:0 frame:0 TX packets:28 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2832 (2.7 KiB) TX bytes:2832 (2.7 KiB) sit0 Link encap:IPv6-in-IPv4 NOARP MTU:1480 Metric:1 RX packets:0 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:0 (0.0 b) TX bytes:0 (0.0 b) vnet0 Link encap:Ethernet HWaddr FE:54:00:3A:C5:C9 inet6 addr: fe80::fc54:ff:fe3a:c5c9/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:492 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:0 (0.0 b) TX bytes:29516 (28.8 KiB)我有兩個物理適配器，eth0 和 eth1。eth1 目前已拔出，未在此設置中使用。eth0 被橋接到 bridge0。bridge0 正在使用 DHCP 獲取其網路配置。適配器使用以下配置：
[root@node2 network-scripts]# cat ifcfg-eth0 DEVICE="eth0" NM_CONTROLLED="no" ONBOOT=yes HWADDR=BC:30:5B:E8:C0:4F BRIDGE=bridge0 [root@node2 network-scripts]# cat ifcfg-bridge0 DEVICE=bridge0 ONBOOT=yes TYPE=Bridge BOOTPROTO=dhcp DELAY=0 NM_CONTROLLED=no…和 iptables 設置如下：
[root@node2 network-scripts]# iptables --list-rules -P INPUT ACCEPT -P FORWARD ACCEPT -P OUTPUT ACCEPT -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 5900 -j ACCEPT -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -m physdev --physdev-is-bridged -j ACCEPT -A FORWARD -m physdev --physdev-is-bridged -j ACCEPT -A FORWARD -j REJECT --reject-with icmp-host-prohibited所以，就是這樣安排的。然後我使用以下命令創建和安裝 Centos6 來賓映像：
virt-install --name=centos-bridge-test --disk path=/var/lib/libvirt/images/centos6-minimal,size=5 --vnc --ram=512 --cdrom=/var/lib/libvirt/images/CentOS-6.0-x86_64-minimal.iso --vnclisten=0.0.0.0 -b bridge0我的理解是，這種設置應該足以讓橋接網路“正常工作”，但是，當我使用virsh命令（virsh start centos-bridge-test）啟動來賓時，它沒有網路連接。
這是 libvirt 域的 xml 轉儲：
[root@node2 network-scripts]# virsh dumpxml centos-bridge-test <domain type='kvm' id='7'> <name>centos-bridge-test</name> <uuid>5d611267-2feb-c6f7-7a48-29f9695a4a75</uuid> <memory>524288</memory> <currentMemory>524288</currentMemory> <vcpu>1</vcpu> <os> <type arch='x86_64' machine='rhel6.0.0'>hvm</type> <boot dev='hd'/> </os> <features> <acpi/> <apic/> <pae/> </features> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <emulator>/usr/libexec/qemu-kvm</emulator> <disk type='file' device='disk'> <driver name='qemu' type='raw' cache='none'/> <source file='/var/lib/libvirt/images/centos6-minimal'/> <target dev='hda' bus='ide'/> <alias name='ide0-0-0'/> <address type='drive' controller='0' bus='0' unit='0'/> </disk> <disk type='block' device='cdrom'> <driver name='qemu' type='raw'/> <target dev='hdc' bus='ide'/> <readonly/> <alias name='ide0-1-0'/> <address type='drive' controller='0' bus='1' unit='0'/> </disk> <controller type='ide' index='0'> <alias name='ide0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/> </controller> <interface type='bridge'> <mac address='52:54:00:3a:c5:c9'/> <source bridge='bridge0'/> <target dev='vnet0'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> <serial type='pty'> <source path='/dev/pts/1'/> <target port='0'/> <alias name='serial0'/> </serial> <console type='pty' tty='/dev/pts/1'> <source path='/dev/pts/1'/> <target port='0'/> <alias name='serial0'/> </console> <input type='mouse' bus='ps2'/> <graphics type='vnc' port='5900' autoport='yes' listen='0.0.0.0' keymap='en-gb'/> <video> <model type='cirrus' vram='9216' heads='1'/> <alias name='video0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> </video> <memballoon model='virtio'> <alias name='balloon0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </memballoon> </devices> <seclabel type='dynamic' model='selinux'> <label>system_u:system_r:svirt_t:s0:c384,c608</label> <imagelabel>system_u:object_r:svirt_image_t:s0:c384,c608</imagelabel> </seclabel> </domain>界面似乎設置正確（通過查看 libvirt 文件）。
因此，每當我啟動來賓時，都沒有網路連接。
[root@localhost ~]# ifconfig -a eth0 Link encap:Ehternet HWaddr 52:54:00:3A:C5:C9 BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) Interrupt:10 Base address:0x6000 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:0 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:0 (0.0 b) TX bytes:0 (0.0 b)**編輯：**請注意 eth0 不在此處，因此我一直在執行ifup eth0以使適配器啟動，然後提供以下輸出：
[root@localhost ~]# ifconfig -a eth0 Link encap:Ehternet HWaddr 52:54:00:3A:C5:C9 inet6 addr: fe80::5054:ff:fe3a:c5c9/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets65 errors:0 dropped:0 overruns:0 frame:0 TX packets:5 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3896 (3.8 KiB) TX bytes:398 (398.0 b) 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:0 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:0 (0.0 b) TX bytes:0 (0.0 b)…當我嘗試訪問網路以獲取內部或外部地址時，我得到了這個：
[root@localhost ~]# ping 10.59.190.253 connect: Network is unreachable [root@localhost ~]# ping www.google.com ping: unknown host www.google.com [root@localhost ~]# ping 173.194.66.99 connect: Network is unreachable**附加資訊：**以下是對此問題的評論要求的一些附加資訊。這些命令是從目前執行來賓的主機上執行的：
[root@node2 network-scripts]# brctl show bridge name bridge id STP enabled interfaces bridge0 8000.bc305be8c04f no eth0 vnet0 [root@node2 network-scripts]# ps -ef | grep qemu qemu 1597 1 0 11:28 ? 00:00:25 /usr/libexec/qemu-kvm -S -M rhel6.0.0 -enable-kvm -m 512 -smp 1,sockets=1,cores=1,threads=1 -name centos-bridge-test -uuid 5d611267-2feb-c6f7-7a48-29f9695a4a75 -nodefconfig -nodefaults -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/centos-bridge-test.monitor,server,nowait -mon chardev=monitor,mode=control -rtc base=utc -boot c -drive file=/var/lib/libvirt/images/centos6-minimal,if=none,id=drive-ide0-0-0,boot=on,format=raw,cache=none -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -drive if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev tap,fd=20,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:3a:c5:c9,bus=pci.0,addr=0x3 -chardev pty,id=serial0 -device isa-serial,chardev=serial0 -usb -vnc 0.0.0.0:0 -k en-gb -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 root 2815 32057 0 14:31 pts/0 00:00:00 grep qemu我真的很感激此刻可能的任何幫助！如果您需要我提供任何進一步的配置等，請告訴我。
**編輯：**我使用的是 Centos6 的最小安裝，所以我沒有安裝任何視窗管理器，所以我試圖通過 virsh 和 virsh-install 來做所有事情，並且想盡量避免使用 virsh-manager。謝謝。
這個問題的答案是，因為我在來賓上完成了 Centos 6 minimum 的非圖形安裝，所以網路介面沒有自動設置為工作。我缺乏對虛擬化和 Centos 的了解，這意味著我認為這會為我解決，但我的這種假設是錯誤的。
修復：我需要進入來賓上的ifcfg-eth0並打開ONBOOT=yes和BOOTPROTO=dhcp ，然後通過ifdown eth0然後ifup eth0重新啟動網路適配器。完成此操作後，客人收到了 IP 地址，一切都按預期工作。