[libvirt-users] vms doesn't coomunicate via network
Laine Stump
laine at redhat.com
Wed Dec 19 02:49:55 UTC 2018
On 12/15/18 9:54 AM, daggs wrote:
> Greetings,
>
> I have two vms, one is a router and the other one is a client, for some reason, the client vm is unable get ip via dhcp from the router vm.
> here are outputs:
> vm1.xml:
> <interface type='bridge'>
> <mac address='52:54:00:54:78:be'/>
> <source bridge='virbr0'/>
> <model type='virtio'/>
> <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
> </interface>
>
> router.xml:
> <interface type='bridge'>
> <mac address='52:54:00:f9:bd:fb'/>
> <source bridge='virbr0'/>
> <target dev='vnet1'/>
> <model type='virtio'/>
> <alias name='net1'/>
> <address type='pci' domain='0x0000' bus='0x0a' slot='0x00' function='0x0'/>
> </interface>
>
> ifconfig > $ busybox ifconfig -a
> dummy0 Link encap:Ethernet HWaddr CE:2E:DD:15:8A:0C
> BROADCAST NOARP 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)
>
> 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:65536 Metric:1
> RX packets:21428 errors:0 dropped:0 overruns:0 frame:0
> TX packets:21428 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:1039176 (1014.8 KiB) TX bytes:1039176 (1014.8 KiB)
>
> virbr0 Link encap:Ethernet HWaddr 52:54:00:7E:27:AF
> inet6 addr: fe80::5054:ff:fe7e:27af/64 Scope:Link
> inet6 addr: fdab:9802:eb52:0:5054:ff:fe7e:27af/64 Scope:Global
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:530861 errors:0 dropped:0 overruns:0 frame:0
> TX packets:85 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:591914339 (564.4 MiB) TX bytes:4042 (3.9 KiB)
>
> virbr0-dummy Link encap:Ethernet HWaddr 52:54:00:7E:27:AF
> UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:141357 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 B) TX bytes:32288355 (30.7 MiB)
>
> vnet0 Link encap:Ethernet HWaddr FE:54:00:8B:66:C1
> inet addr:10.0.0.3 Bcast:10.0.0.255 Mask:255.255.255.0
> inet6 addr: fdab:9802:eb52:0:fc54:ff:fe8b:66c1/64 Scope:Global
How did vnet0 get IP addresses? They aren't in the domain xml, and the
guest has no visibility to change the IP of the tap interface on the
host side. That means that you have "something else" messing around with
the networking config. I can't say what it is, but this is definitely a
red flag that needs investigating - the host side of tap devices should
not have an IP address except in special cases when you're routing
directly from host to guest using the tap and *not* using a bridge.
> inet6 addr: fe80::fc54:ff:fe8b:66c1/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:261801 errors:0 dropped:0 overruns:0 frame:0
> TX packets:438289 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:42370344 (40.4 MiB) TX bytes:895415306 (853.9 MiB)
>
> vnet1 Link encap:Ethernet HWaddr FE:54:00:F9:BD:FB
> inet6 addr: fe80::fc54:ff:fef9:bdfb/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:531064 errors:0 dropped:0 overruns:0 frame:0
> TX packets:262 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:599366518 (571.5 MiB) TX bytes:27088 (26.4 KiB)
>
> /etc/network/interface:
> $ cat /etc/network/interfaces
> # This file describes the network interfaces available on your system
> # and how to activate them. For more information, see interfaces(5).
>
> source /etc/network/interfaces.d/*
>
> # The loopback network interface
> auto lo
> iface lo inet loopback
>
> # The primary network interface
> #allow-hotplug enx503eaa4f9dcd
> #iface enx503eaa4f9dcd inet dhcp
> #allow-hotplug enp0s31f6
> #iface enp0s31f6 inet dhcp
>
> allow-hotplug vnet0
> iface vnet0 inet dhcp
Ah. Why are you doing this^^^ ?? It makes no sense at all. The tap
devices should not be listed at all in the host's network config; they
are created and configured by libvirt directly.
>
> auto virbr0-dummy
> iface virbr0-dummy inet manual
> pre-up /sbin/ip link add virbr0-dummy type dummy
> up /sbin/ip link set virbr0-dummy address 52:54:00:7e:27:af
>
> auto virbr0
> iface virbr0 inet manual
> hwaddress ether 19:7c:3b:92:ec:ee
> bridge_ports virbr0-dummy
Likewise for both of these. The bridge created by libvirt for its
default network is usually named virbr0. You don't have both a libvirt
default network that uses virbr0 *and* this manual configuration of
virbr0 in your interfaces file too, do you? That would be a recipe for
disaster.
>
> any ideas what cen be the issue?
1) You haven't shown anything to indicate your guest named "router"
actually has a dhcp server running.
2) Based on the oddities I've mentioned above, it sounds like you may
have conflicting/nonsensical config that isn't shown in this email.
> Thanks,
>
> Dagg.
>
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