neutron

Use Linux bridge to assign networks, but not IPs

Asked by Zak Estrada

I have setup quantum with the linux bridge plugin. For now, I'm not looking to do IPAM in quantum, just to create networks. I want to assign VMs to networks without IP subnets, but if i do that then nova doesn't create network interfaces for those VMs (no errors in either compute.log or linuxbridge-agent.log).

Here's an example:
---
[root@cloud1 ~(keystone_admin)]# quantum net-create lab-test --tenant_id 60899984662e4f38b703f7126de48473 --provider:network_type flat --provider:physical_network testnet
Created a new network:
+---------------------------+--------------------------------------+
| Field | Value |
+---------------------------+--------------------------------------+
| admin_state_up | True |
| id | 29989e92-3210-4d7c-af1b-dba53165352b |
| name | lab-test |
| provider:network_type | flat |
| provider:physical_network | testnet |
| provider:segmentation_id | |
| router:external | False |
| shared | False |
| status | ACTIVE |
| subnets | |
| tenant_id | 60899984662e4f38b703f7126de48473 |
+---------------------------+--------------------------------------+
---

---
[root@cloud1 ~(keystone_user)]$ nova boot --flavor m1.small --image rh6 --nic net-id=29989e92-3210-4d7c-af1b-dba53165352b test
---

testnet does exist in the plugin.ini:
---
network_vlan_ranges = testnet:100:200
...
physical_interface_mappings = testnet:vbr-em1
---

Inside the vm, I only have the "lo" interface. If I create a subnet, then an eth0 device gets created. I've tried both "flat" and "vlan" for network_type.

What's the right way to do this?

Thanks!

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Revision history for this message
yong sheng gong (gongysh) said : 		#1

create a subnet and then boot instance.

Revision history for this message
Zak Estrada (zestrada) said : 		#2

If I create a subnet, that requires specifying a CIDR and it assigns an IP
to the instance. While I don't have DHCP enabled, quantum still appears to
do IPAM.

Thanks!
On May 24, 2013 5:03 AM, "yong sheng gong" <
<email address hidden>> wrote:

> Your question #229425 on quantum changed:
> https://answers.launchpad.net/quantum/+question/229425
>
> Status: Open => Answered
>
> yong sheng gong proposed the following answer:
> create a subnet and then boot instance.
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
> https://answers.launchpad.net/quantum/+question/229425/+confirm?answer_id=0
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/quantum/+question/229425
>
> You received this question notification because you asked the question.
>

Revision history for this message
Zak Estrada (zestrada) said : 		#3

I suppose one thing that might make this question more clear is to specify that I'm only trying to use quantum for L2 networking (i.e. creating tagged VLANs) and not for managing L3 subnets/addresses/etc. Is this possible?

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Launchpad Janitor (janitor) said : 		#4

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

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Zak Estrada (zestrada) said : 		#5

This issue still exists, closed by janitor so I'm commenting to reopen.
On Jun 12, 2013 4:18 AM, "Launchpad Janitor" <
<email address hidden>> wrote:

> Your question #229425 on quantum changed:
> https://answers.launchpad.net/quantum/+question/229425
>
> Status: Open => Expired
>
> Launchpad Janitor expired the question:
> This question was expired because it remained in the 'Open' state
> without activity for the last 15 days.
>
> --
> If you're still having this problem, you can reopen your question either
> by replying to this email or by going to the following page and
> entering more information about your problem:
> https://answers.launchpad.net/quantum/+question/229425
>
> You received this question notification because you asked the question.
>

Revision history for this message
Launchpad Janitor (janitor) said : 		#6

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Revision history for this message
Zak Estrada (zestrada) said : 		#7

This issue still stands. I can manage L2 VLANs fine with quantum, but not
without assigning a subnet/IP. It makes things confusing, especially if I
have separate networks that will actually get IPs from quantum.
On Jun 28, 2013 5:16 AM, "Launchpad Janitor" <
<email address hidden>> wrote:

> Your question #229425 on neutron changed:
> https://answers.launchpad.net/neutron/+question/229425
>
> Status: Open => Expired
>
> Launchpad Janitor expired the question:
> This question was expired because it remained in the 'Open' state
> without activity for the last 15 days.
>
> --
> If you're still having this problem, you can reopen your question either
> by replying to this email or by going to the following page and
> entering more information about your problem:
> https://answers.launchpad.net/neutron/+question/229425
>
> You received this question notification because you asked the question.
>

Revision history for this message
Launchpad Janitor (janitor) said : 		#8

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Revision history for this message
Zak Estrada (zestrada) said : 		#9

Not sure how to get traction on this
On Jul 14, 2013 4:26 AM, "Launchpad Janitor" <
<email address hidden>> wrote:

> Your question #229425 on neutron changed:
> https://answers.launchpad.net/neutron/+question/229425
>
> Status: Open => Expired
>
> Launchpad Janitor expired the question:
> This question was expired because it remained in the 'Open' state
> without activity for the last 15 days.
>
> --
> If you're still having this problem, you can reopen your question either
> by replying to this email or by going to the following page and
> entering more information about your problem:
> https://answers.launchpad.net/neutron/+question/229425
>
> You received this question notification because you asked the question.
>

Revision history for this message
Edgar Magana (emagana) said : 		#10

Did you try creating network and subnet with NO DHCP?
You can do the following:
quantum subnet-create network-name 192.168.0.0/24 --enable_dhcp False

Revision history for this message
Zak Estrada (zestrada) said : 		#11

That does work, but then I'm 'assigning' an IP in neutron (even though I'm
not using it).

Thanks!
--Zak
On Jul 14, 2013 6:21 PM, "Edgar Magana" <
<email address hidden>> wrote:

> Your question #229425 on neutron changed:
> https://answers.launchpad.net/neutron/+question/229425
>
> Status: Open => Answered
>
> Edgar Magana proposed the following answer:
> Did you try creating network and subnet with NO DHCP?
> You can do the following:
> quantum subnet-create network-name 192.168.0.0/24 --enable_dhcp False
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
> https://answers.launchpad.net/neutron/+question/229425/+confirm?answer_id=9
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/neutron/+question/229425
>
> You received this question notification because you asked the question.
>

Revision history for this message
Launchpad Janitor (janitor) said : 		#12

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Revision history for this message
Zak Estrada (zestrada) said : 		#13

Reopening
On Jul 31, 2013 4:31 AM, "Launchpad Janitor" <
<email address hidden>> wrote:

> Your question #229425 on neutron changed:
> https://answers.launchpad.net/neutron/+question/229425
>
> Status: Open => Expired
>
> Launchpad Janitor expired the question:
> This question was expired because it remained in the 'Open' state
> without activity for the last 15 days.
>
> --
> If you're still having this problem, you can reopen your question either
> by replying to this email or by going to the following page and
> entering more information about your problem:
> https://answers.launchpad.net/neutron/+question/229425
>
> You received this question notification because you asked the question.
>

Revision history for this message
Salvatore Orlando (salvatore-orlando) said : 		#14

Hi Zak,

this is unfortunately the way nova works.
If you're using security groups, then you need a subnet, otherwise nova will raise when booting a VM.
If not, you can try and boot the VM passing a pre-created neutron port with:

nova boot .... --nic port-id=<neutron_port_id>

If that does not work either we'll see whether it is worth opening a bug for allowing this use case.

Revision history for this message
Zak Estrada (zestrada) said : 		#15

Unfortunately, when I create a a port on a network with no subnet/IP associated with it, no network device is created on the instance. Namely, "ifconfig -a" only returns the loopback device. After allocating a subnet, nova will plumb a network device.

It seems like this is how nova works, as you've pointed out. Should I reopen this as a bug?

Revision history for this message
Salvatore Orlando (salvatore-orlando) said : 		#16

I think you can either ask the saame question in nova - or transform this in a bug, targeting both nova and neutron (even if I think no change might be required on the neutron side).

This will probably get some nova developers too in the discussion.

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