Hi Daniel,
Yes you could do .1q at an interface level for the VR ( this is what we do with
KVM networking ). However this brings you a couple of stumbling blocks:
1) For you to trunk VLANs to this interface it would need to be attached to a
trunked vSwitch – which is currently all or nothing in VMware (by setting vlan
for the vSwitch to 4095) – i.e. you can’t set a vSwitch to only trunk certain
VLAN ranges. This now brings you a further problem – if you did trunk at the
vSwitch level you would have to configure your top of rack switches to do the
same. Again – this is possible – but when you consider that you *must* be able
to isolate all VLAN traffic on a per CloudStack account level – this would mean
you would need one or more ESXi physical NICs per account + a considerable
count of top of rack physical switch ports. So – you are effectively moving the
problem from the virtual switches to the physical ones, which while technically
possible is not feasible.
2) Your main problem is at the user VM end. If we agree you can’t expect VLAN
tags to be set at the guest OS level then the only other place to set this is
at the vSwitch level. Keeping in mind the limitations mentioned above this
means you need at least one vSwich ( = VLAN ) per VPC tier. Since there is no
way other than the all-in trunking mentioned above for the VPC VR to connect to
all of these tier vSwitches implementing .1q at the VR level would not work.
Keep in mind though – my points above are purely in the context of VMware and
VLANs – as soon as you step into the SDN world you move to overlay networks etc
where other mechanisms could be and are implemented.
= =
Dennis – to answer your question as well – CloudStack speaks to XenServer using
the API. I think you have probably answered your own question though – as you
pointed out in your discussion forum thread all documentation says 7 NICs is
the max supported. If you do some testing and find the API can handle more than
7 then I would suggest to log a Jira ticket such that this can be implemented
in future CloudStack versions.
Regards,
Dag Sonstebo
Cloud Architect
ShapeBlue
On 15/08/2017, 14:10, "daniel.herrm...@zv.fraunhofer.de"
<daniel.herrm...@zv.fraunhofer.de> wrote:
Hi Dag,
you would need to do that with the Linux dot1q kernel module, yes. This way
you can create virtual interfaces with VLAN tags and bind them to one NIC. We
are routing and firewalling in software anyway, I do not see any considerable
additional overhead here. Instead of “physical” NICs, we have one of them and
create the other as VLAN interface.
I do not really understand the security problems as well. No user is ever
expected to have access to the virtual router. So how would that affect
security?
Regards
Daniel
Am 15.08.17, 14:36 schrieb "Dag Sonstebo" <dag.sonst...@shapeblue.com>:
Hi Daniel,
The mechanism for isolating L2 traffic is at the vSwitch level – there
is no way to VLAN tag the at the NIC level for a VM in VMware. Your only other
option is therefore to VLAN tag at the guest OS level which adds security
issues + overhead, etc.
Regards,
Dag Sonstebo
Cloud Architect
ShapeBlue
On 15/08/2017, 13:05, "daniel.herrm...@zv.fraunhofer.de"
<daniel.herrm...@zv.fraunhofer.de> wrote:
Hi Dag,
thank you for your answer. As far as I know, the end user never has
direct access to the virtual router. I am not talking about adding a VLAN tag
at the user VM, only at the VPR, where the limit most likely comes into play
when creating a number of tiers in a VPC.
We could do both: normal VMs require one interface per
tier/network, which makes perfect sense. The router however could use VLAN tags
at VM level, which could remove the limitation of having a maximum number of
tiers connected to one VPC. It is only configured by CloudStack, the end user
does not have access to the VPR.
Regards
Daniel
Am 15.08.17, 13:27 schrieb "Dag Sonstebo"
<dag.sonst...@shapeblue.com>:
Hi Daniel,
In theory that could work – but keep in mind we are working in
a multi-tenant environment, where guest isolation must be guaranteed, hence
cannot ever be exposed to normal users. The isolation method must be abstracted
from the end user VMs – otherwise you would have a potential security issue
where someone could tag traffic from their VM with someone else’s tag. Doing
tagging at VM level would also be a huge overhead.
As a result we VLAN tag at the vSwitch or bridge level – which
end users have no access to – the flipside of the coin being that this requires
separate NICs for each tier.
Regards,
Dag Sonstebo
Cloud Architect
ShapeBlue
On 15/08/2017, 11:07, "daniel.herrm...@zv.fraunhofer.de"
<daniel.herrm...@zv.fraunhofer.de> wrote:
Hi,
we are hitting the same limitation, except that we can use
10 NICs on VMware.
The fact that we also use the Private Gateway functionality
addes another NIC, besides the management and outside NIC which is present as
well.
I wonder that is the reason for one NIC per tier? Why not
just use one outside NIC, one management NIC and *one* NIC for the tiers, where
the VLANs (or whatever isolation method is used) is trunked, for example just
using subinterfaces and dot1Q tags? This would eliminate this limit for
whatever hypervisor that supports trunk to it’s guests (I know for sure about
VMWare, not so much about the other hypervisors).
Regards
Daniel
Am 15.08.17, 10:52 schrieb "Dag Sonstebo"
<dag.sonst...@shapeblue.com>:
Hi Dennis,
Any tier or network which is accessible and part of a
VPC requires an interface on the VPC Virtual Router.
What you can however do is create separate shared
networks and connect these as secondary networks to your VMs – these shared
networks get their own VR.
Regards,
Dag Sonstebo
Cloud Architect
ShapeBlue
On 15/08/2017, 09:19, "Dennis Meyer"
<snooop...@gmail.com> wrote:
Hi,
im using xenserver as hypervisor so im limited to 7
nic's / vm, so the
router vm cant handle more than 7 nics which
corresponds to 7 networks
inside a vpc. I had created some networks for
different drbd and corosync
stuff, they dont need a gateway, dhcp and a router
vm. How should a network
offering look like which dont creates a network on
the routervm but is
accessible by the vpc?
Snooops
dag.sonst...@shapeblue.com
www.shapeblue.com
53 Chandos Place, Covent Garden, London WC2N 4HSUK
@shapeblue
dag.sonst...@shapeblue.com
www.shapeblue.com
53 Chandos Place, Covent Garden, London WC2N 4HSUK
@shapeblue
dag.sonst...@shapeblue.com
www.shapeblue.com
53 Chandos Place, Covent Garden, London WC2N 4HSUK
@shapeblue
dag.sonst...@shapeblue.com
www.shapeblue.com
53 Chandos Place, Covent Garden, London WC2N 4HSUK
@shapeblue
