[gentoo-user] OT: networking and libvirt

[gentoo-user] OT: networking and libvirt

[William Kenworthy]

I am setting up a libvirt managed vm system on a gentoo server that will
have a number of gentoo vm's - web, calendar/mail, ...  Eventually I'll
have two servers and migration will be needed.

What do people who do this use for networking? - I have the native
libvert nat working but I prefer a routed subnet and not nat.  I used a
tap and vde on my older non-libvirt system ... but it seems vde is not
an option, but it looks like vlans, macvlan etc will work.

So what is usually recommended and works for this scenario?

BillK

Re: [gentoo-user] OT: networking and libvirt

[Randy Barlow]

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On 01/20/2013 12:37 AM, William Kenworthy wrote:
> So what is usually recommended and works for this scenario?

I personally use a bridged interface that allows my VMs to be on the
"physical" network. That works out pretty well. In my use case, it's
the same subnet as the host, but it should be possible to use VLANs to
accomplish having them on a separate subnet.

- -- 
R
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Re: [gentoo-user] OT: networking and libvirt

[Michael Mol]

On Mon, Jan 28, 2013 at 5:35 PM, Randy Barlow
<randy@electronsweatshop.com> wrote:
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> Hash: SHA1
>
> On 01/20/2013 12:37 AM, William Kenworthy wrote:
>> So what is usually recommended and works for this scenario?
>
> I personally use a bridged interface that allows my VMs to be on the
> "physical" network. That works out pretty well. In my use case, it's
> the same subnet as the host, but it should be possible to use VLANs to
> accomplish having them on a separate subnet.

There's no requirement that they be on separate layer 2 segments if
you want them to be on separate layer 3 subnets.

Either statically configure the IPs, or:

For IPv4: Have DHCP grant IPs from different pools based on source MAC
or declared hostname.

For IPv6: Use DHCPv6 rather than SLAAC, and follow the same principles
as for DHCP-for-IPv4.

Sure, giving them separate layer 2 segments helps encapsulation (and
may make things easier from an autoconfiguration standpoint,
depending), but it's not strictly necessary from a technology point of
view.

--
:wq

Re: [gentoo-user] OT: networking and libvirt

[Dustin C. Hatch]

On 1/28/2013 17:52, Michael Mol wrote:
> On Mon, Jan 28, 2013 at 5:35 PM, Randy Barlow
> <randy@electronsweatshop.com> wrote:
>> On 01/20/2013 12:37 AM, William Kenworthy wrote:
>>> So what is usually recommended and works for this scenario?
>>
>> I personally use a bridged interface that allows my VMs to be on the
>> "physical" network. That works out pretty well. In my use case, it's
>> the same subnet as the host, but it should be possible to use VLANs to
>> accomplish having them on a separate subnet.
I've got a Gentoo-based libvirt/qemu-kvm host running with several VMs, 
also using bridged TAP adapters. It works really well for servers/other 
"always on" systems that run in the background. virt-manager can handle 
everything for you, you just have to know the name of the bridge to 
which you want to the VM to join.
>
> There's no requirement that they be on separate layer 2 segments if
> you want them to be on separate layer 3 subnets.
>
> Either statically configure the IPs, or:
>
> For IPv4: Have DHCP grant IPs from different pools based on source MAC
> or declared hostname.
>
> For IPv6: Use DHCPv6 rather than SLAAC, and follow the same principles
> as for DHCP-for-IPv4.
>
> Sure, giving them separate layer 2 segments helps encapsulation (and
> may make things easier from an autoconfiguration standpoint,
> depending), but it's not strictly necessary from a technology point of
> view.
>
While that's all true, I personally think 802.1Q VLANs are *much* easier 
to configure than DHCP and especially DHCPv6. Definitely sysadmin's 
prerogative, though.
> --
> :wq
>
:x

-- 
♫Dustin

Re: [gentoo-user] OT: networking and libvirt

[William Kenworthy]

On 29/01/13 08:04, Dustin C. Hatch wrote:
> On 1/28/2013 17:52, Michael Mol wrote:
>> On Mon, Jan 28, 2013 at 5:35 PM, Randy Barlow
>> <randy@electronsweatshop.com> wrote:
>>> On 01/20/2013 12:37 AM, William Kenworthy wrote:
>>>> So what is usually recommended and works for this scenario?
>>>
>>> I personally use a bridged interface that allows my VMs to be on the
>>> "physical" network. That works out pretty well. In my use case, it's
>>> the same subnet as the host, but it should be possible to use VLANs to
>>> accomplish having them on a separate subnet.
> I've got a Gentoo-based libvirt/qemu-kvm host running with several
> VMs, also using bridged TAP adapters. It works really well for
> servers/other "always on" systems that run in the background.
> virt-manager can handle everything for you, you just have to know the
> name of the bridge to which you want to the VM to join.
>>
>> There's no requirement that they be on separate layer 2 segments if
>> you want them to be on separate layer 3 subnets.
>>
>> Either statically configure the IPs, or:
>>
>> For IPv4: Have DHCP grant IPs from different pools based on source MAC
>> or declared hostname.
>>
>> For IPv6: Use DHCPv6 rather than SLAAC, and follow the same principles
>> as for DHCP-for-IPv4.
>>
>> Sure, giving them separate layer 2 segments helps encapsulation (and
>> may make things easier from an autoconfiguration standpoint,
>> depending), but it's not strictly necessary from a technology point of
>> view.
>>
> While that's all true, I personally think 802.1Q VLANs are *much*
> easier to configure than DHCP and especially DHCPv6. Definitely
> sysadmin's prerogative, though.
>> -- 
>> :wq
>>
> :x
>
I went with openvswitch and a tap on the host so I could route into the
rest of the network.  The vmś will have to use fixed IP addresses
(servers one of which will be dns/dhcp for the clients)  I will be using
vlans eventually, but need a managed switch with more ports which is in
the ¨plan¨

BillK