Re: [libvirt] [PATCH] lxc: support <interface type='ethernet'>
2016-05-24 19:33 GMT+03:00 Laine Stump <laine(a)laine.org>:
So ignoring the IPv6 addresses for now. You now have a tap device on the
*host* that has the following IP addresses:
$HOST_IP peer $VM_IP/32
$VM_GW
169.254.169.254
I'm guessing that in the guest you configure its ethernet to have
$VM_IP peer $HOST_IP/24 (or some other prefix < 32)
route add default $VM_GW ($VM_GW on same subnet as $HOST_IP/24)
No, inside guest i'm assign address via dhcp to $VM_IP/24 (not using peer)
and route add default $VM_GW
peer only used on host machine to determine on which interface kernel
needs to send traffic
(I'm not sure what the guest does with 169.254.169.254)
What if you instead set the host to:
$HOST_IP peer $VM_IP/32
and set the guest to:
$VM_IP peer $HOST_IP/32
route add default $HOST_IP
??
I don't use this scheme... If i set $VM_IP peer $HOST_IP/32 on host
machine i think kernel recieves packet and drop it =)
Anyway, it's important to know if you set the IP config on host
and guest to
exact mirrors of each other. It seems like the answer is "no", though, so
i'm going to make a patch that allows what I was talking about last week:
<interface type='ethernet'>
<source>
<ip address='HOST_IP' family='ipv4' peer='VM_IP'
prefix='32'/>
<ip address='VM_GW' family='ipv4'
prefix='32'/>
</source>
<ip address='VM_IP' family='ipv4' peer='HOST_IP'
prefix='24'/>
<route family='ipv4' address='0.0.0.0'
gateway='HOST_IP'/>
...
</interface>
On qemu only the address info inside <source> would be used, since we don't
have control over the guest's network config. On LXC, we can set both.
Does that sound usable?
Yes, but don't cleanup please <ip address='VM_IP' family='ipv4'
peer='HOST_IP' prefix='24'/> in qemu case, because on somedays we can
launch dnsmasq or orhet software that can provide dhcp and use this
element..
--
Vasiliy Tolstov,
e-mail: v.tolstov(a)yoctocloud.net