Greetings Laine,
> Sent: Monday, April 30, 2018 at 8:31 PM
> From: "Laine Stump" <laine@xxxxxxxxxx>
> To: libvirt-users@xxxxxxxxxx
> Cc: daggs <daggs@xxxxxxx>
> Subject: Re: connecting host and guest vm using a dummy nic
>
> On 04/27/2018 06:39 PM, daggs wrote:
> > Greetings all,
> >
> > I have a host machine that runs a router within a vm.
> > I want to allow a connection between the host and the guest so the host can connect to the lan provided by the router vm.
> > I've created a dummy interface with these commands:
> > $ ip link add ens99-dummy type dummy
> > $ ip link set ens99-dummy address 52:54:00:1f:d0:ff
> >
> > this resulted with this output:
> > $ ifconfig ens99-dummy
> > ens99-dummy Link encap:Ethernet HWaddr 52:54:00:1F:D0:FF
> > inet6 addr: fe80::84b5:24ff:fe62:c16d/64 Scope:Link
> > UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
> > RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> > TX packets:899 errors:0 dropped:0 overruns:0 carrier:0
> > collisions:0 txqueuelen:1000
> > RX bytes:0 (0.0 B) TX bytes:321727 (314.1 KiB)
> >
> >
> > in my libvirt's xml file I have this entry:
> > <interface type='direct'>
> > <mac address='52:54:00:0c:cb:3e'/>
> > <source dev='ens99-dummy' mode='private'/>
> > <target dev='macvtap0'/>
> > <model type='e1000'/>
> > <alias name='net0'/>
> > <address type='pci' domain='0x0000' bus='0x02' slot='0x01' function='0x0'/>
> > </interface>
>
> MY first question would be "Why are you using macvtap?" This
> unnecessarily complicates the plumbing, leading to more potential places
> where it could fail.
misconfiguration, question is, what should be the exact config for this.
>
> The 2nd question is - Have you looked at the dhcp server running on the
> guest to verify that it is indeed listening for DHCP requests on the
> guest-side interface associated with the macvtap interface, and that it
> is receiving those requests and sending a reply?
will test it. as said before, I'm not sure what should be the proper config in libvirt.
>
> >
> > after the vm is up, I see the adapter in the vm and the host has one more entry:
> > $ ifconfig macvtap0
> > macvtap0 Link encap:Ethernet HWaddr 52:54:00:0C:CB:3E
> > inet6 addr: fe80::5054:ff:fe0c:cb3e/64 Scope:Link
> > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> > RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> > TX packets:889 errors:0 dropped:0 overruns:0 carrier:0
> > collisions:0 txqueuelen:500
> > RX bytes:0 (0.0 B) TX bytes:320523 (313.0 KiB)
> >
> > but when I try to request ip via dhcp from both macvtap0 and ens99-dummy I don't get any.
> > any idea why?
>
> Definitely you wouldn't be able to use the macvtap0 device, so if
> anything you would want to be using ens99-dummy, but I'm not even
> certain *that* would work, as I've never tried it.
so use ens99-dummy directly?
>
> You've provided no visibility into the configuration of the guest OS in
> your virtual machine, but in general if you want a simple connection
> between the host and guest that has *no other connections*, you can do
> this with a bare tap device:
>
> <interface type='ethernet'>
> <model type='e1000'/>
> </interface>
>
> This will show up as a single device on the host and a single device in
> the guest, not connected to a bridge or a macvtap device or anything,
> and will not need any other "ip link blah blah" type setup on the host.
> Simplifying your setup in this manner may make it easier to find the
> source of your problem.
>
ok, here is the entire xml file:
<domain type='kvm'>
<name>router</name>
<uuid>ed8eabe2-ced3-4224-aa12-60fb31dd3fd4</uuid>
<memory unit='KiB'>1048576</memory>
<currentMemory unit='KiB'>1048576</currentMemory>
<vcpu placement='static'>2</vcpu>
<os>
<type arch='x86_64' machine='pc-q35-2.8'>hvm</type>
<boot dev='hd'/>
</os>
<features>
<acpi/>
<apic/>
</features>
<cpu mode='host-passthrough'/>
<clock offset='utc'>
<timer name='rtc' tickpolicy='catchup'/>
<timer name='pit' tickpolicy='delay'/>
<timer name='hpet' present='no'/>
</clock>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>restart</on_crash>
<pm>
<suspend-to-mem enabled='no'/>
<suspend-to-disk enabled='no'/>
</pm>
<devices>
<emulator>/usr/bin/kvm</emulator>
<disk type='file' device='disk'>
<driver name='qemu' type='raw'/>
<source file='/home/router/lede-x86-64-combined-ext4.img'/>
<target dev='vda' bus='virtio'/>
<address type='pci' domain='0x0000' bus='0x05' slot='0x00' function='0x0'/>
</disk>
<controller type='usb' index='0' model='ich9-ehci1'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1d' function='0x7'/>
</controller>
<controller type='usb' index='0' model='ich9-uhci1'>
<master startport='0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1d' function='0x0' multifunction='on'/>
</controller>
<controller type='usb' index='0' model='ich9-uhci2'>
<master startport='2'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1d' function='0x1'/>
</controller>
<controller type='usb' index='0' model='ich9-uhci3'>
<master startport='4'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1d' function='0x2'/>
</controller>
<controller type='sata' index='0'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
</controller>
<controller type='pci' index='0' model='pcie-root'/>
<controller type='pci' index='1' model='dmi-to-pci-bridge'>
<model name='i82801b11-bridge'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1e' function='0x0'/>
</controller>
<controller type='pci' index='2' model='pci-bridge'>
<model name='pci-bridge'/>
<target chassisNr='2'/>
<address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</controller>
<controller type='pci' index='3' model='pcie-root-port'>
<model name='ioh3420'/>
<target chassis='3' port='0x8'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0' multifunction='on'/>
</controller>
<controller type='pci' index='4' model='pcie-root-port'>
<model name='ioh3420'/>
<target chassis='4' port='0x9'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
</controller>
<controller type='pci' index='5' model='pcie-root-port'>
<model name='ioh3420'/>
<target chassis='5' port='0xa'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
</controller>
<controller type='pci' index='6' model='pcie-root-port'>
<model name='ioh3420'/>
<target chassis='6' port='0xb'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x3'/>
</controller>
<controller type='pci' index='7' model='pcie-root-port'>
<model name='ioh3420'/>
<target chassis='7' port='0xc'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x4'/>
</controller>
<controller type='pci' index='8' model='pcie-root-port'>
<model name='ioh3420'/>
<target chassis='8' port='0xd'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x5'/>
</controller>
<interface type='direct'>
<mac address='52:54:00:e7:90:bc'/>
<source dev='ens99-dummy' mode='vepa'/>
<model type='rtl8139'/>
<address type='pci' domain='0x0000' bus='0x02' slot='0x01' function='0x0'/>
</interface>
<serial type='pty'>
<target type='isa-serial' port='0'/>
</serial>
<console type='pty'>
<target type='serial' port='0'/>
</console>
<input type='mouse' bus='ps2'/>
<input type='keyboard' bus='ps2'/>
<hostdev mode='subsystem' type='usb' managed='yes'>
<source>
<vendor id='0x148f'/>
<product id='0x5572'/>
</source>
<address type='usb' bus='0' port='1'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<source>
<address domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</source>
<address type='pci' domain='0x0000' bus='0x03' slot='0x00' function='0x0'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<source>
<address domain='0x0000' bus='0x03' slot='0x00' function='0x0'/>
</source>
<address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<source>
<address domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
</source>
<address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/>
</hostdev>
<memballoon model='virtio'>
<address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
</memballoon>
</devices>
</domain>
what I don't get is how to connect the interface above to the dummy one I've created.
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