Linux interface networking bride configuration to test KVM nested VM

Question

Linux interface networking bride configuration to test KVM nested VM

William TP 20

For testing purposes, I'm setting up an Azure VM Oracle Linux to test KVM. I attach 2 NIC. One primary with a single ipconfig, and a secon one NIC with a 10 ipconfigs. When I start the VM I see the 2 interfaces with the IPs configured.

Are we able to manage the Azure VM network configuration. It seems the network configuration is managed by cloud-init but changes on cloud-init VM regarding network doesn't take effect.
Also, if I manually add the configuration bridge in /etc/sysconfig/network-scripts, IP's remains in eth1 when I set the specific IP's for the bridge. I can see the same IP's on the eth1 and on the related bridge.
Is it possible to have VM inside VM's?

Thanks!

Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-23T01:43:55.58+00:00

Hi @William TP,

Hope you are having a great day.

Just checking in to see if you have got a chance to see my response to your question in resolving the issue.

If you are still facing any further issues, please don't hesitate to reach out to us. We are happy to assist you.

Looking forward to your response and appreciate your time on this.

Regards,

Sai Prasanna.
William TP 20 Reputation points

2024-10-23T10:20:24.01+00:00
Thank you @Sai Prasanna Sinde ,

Regarding your answers:

Thanks

Let me give more details at the bottom.

Thanks for confirming

About the use case. We want to test a virtualization software CloudStack. We're doing on our hardware but we want to test also on cloud VM's. To do this, we need to have a VM with nested virtualization and KVM + libvirt. To do this we need to have at least one NIC with a linux bridge. Something like the following:
William TP 20 Reputation points

2024-10-23T10:21:07.7866667+00:00
In the ifcfg-eth0

DEVICE=eth0 HWADDR=XXX ONBOOT=yes HOTPLUG=no BOOTPROTO=none TYPE=Ethernet BRIDGE=cloudbr0

In the ifcfg-cloudbr0

DEVICE=cloudbr0 TYPE=Bridge ONBOOT=yes BOOTPROTO=none IPV6INIT=no IPV6_AUTOCONF=no DELAY=5 IPADDR=<NIC DHCP> GATEWAY=<AZURE NETWORK GW> NETMASK=<AZURE NETWORK MASK> STP=yes

The new nested VM inside this host will take this bridge cloudbr0 as the network interface from the KVM network. This means that the CloudStack will create a KVM VM assigning an Azure network IP and network should work.

To summarize, I'm aware that I can have a NIC with multiple IP's from Azure network, but I couldn't find a way to define a network bridge to overlap the Azure default configuration to make this kind of definition.

Thanks
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-24T17:52:11.8366667+00:00
Hi @William TP,

Thanks for getting back.

As these things looks to be non-Microsoft related and whatever configuration which you have done so far needs to be investigated by the third-party KVM.

Create a KVM VM and Cloud stack, this looks like OS level virtualization, so please check with the distros.

Whatever the virtualization you are trying to run, it looks like it needs an investigation by third-party as or to the distros. Kindly let us know if the above helps or you need further assistance on this issue.

Thanks,

Sai Prasanna.
William TP 20 Reputation points

2024-10-25T05:37:58.06+00:00

Hello @Sai Prasanna Sinde ,

Understood. Thanks. Only one doubt about VM and Azure. Which is the way in Azure to make custom changes in the VM networking and persist them? If we edit the network inside it every restarts cloud init reconfigures it. And if we add the "network:" section in cloud init this is ignored.

Thanks
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-28T08:40:13.9566667+00:00

Hi @William TP,

Thanks for getting back.

Please disable the Cloud-Init Networking and manually configure the network interfaces and after making changes, restart the networking service to apply you can also use the Custom Script Extension to run configuration scripts that applies to your networking settings post-deployment.

Kindly let us know if the above helps or you need further assistance on this issue.

Regards,

Sai Prasanna.
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-29T01:43:02.2433333+00:00

Hi @William TP,

Greetings,

I would like to follow up with the thread.

Just checking in to see if you have got a chance to see my response to your question in resolving the issue.

If you are still facing any further issues, please don't hesitate to reach out to us. We are happy to assist you.

Looking forward to your response and appreciate your time on this.

Regards,

Sai Prasanna.
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-30T00:57:50.98+00:00

Hi @William TP,

Greetings,

I would like to follow up with the thread.

Just checking in to see if you have got a chance to see my response to your question in resolving the issue.

If you are still facing any further issues, please don't hesitate to reach out to us. We are happy to assist you.

Looking forward to your response and appreciate your time on this.

Regards,

Sai Prasanna.
William TP 20 Reputation points

2024-10-30T06:08:57.31+00:00

Hi @Sai Prasanna Sinde ,I didn't have the chance to try it, but I'll do when I can. If I've more issues I will ask. In the meantime I think we can close the ticket.

Thanks!
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-30T06:20:58.7533333+00:00

Hi @William TP,

Thanks for the confirmation.

I have converted my comment into an answer.

To close this thread, please click **Accept Answer** and **Yes** for was this answer helpful so that other community members facing the same issue can find the right answers.

And, if you have any further query do let us know. We are pleased to assist you.

Your contribution is highly appreciated.

Regards,

Sai Prasanna.

Accepted answer

0 additional answers

Your answer

Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-23T01:43:55.58+00:00

Hi @William TP,

Hope you are having a great day.

Just checking in to see if you have got a chance to see my response to your question in resolving the issue.

If you are still facing any further issues, please don't hesitate to reach out to us. We are happy to assist you.

Looking forward to your response and appreciate your time on this.

Regards,

Sai Prasanna.
William TP 20 Reputation points

2024-10-23T10:20:24.01+00:00

Thank you @Sai Prasanna Sinde ,

Regarding your answers:

Thanks

Let me give more details at the bottom.

Thanks for confirming

About the use case. We want to test a virtualization software CloudStack. We're doing on our hardware but we want to test also on cloud VM's. To do this, we need to have a VM with nested virtualization and KVM + libvirt. To do this we need to have at least one NIC with a linux bridge. Something like the following:
William TP 20 Reputation points

2024-10-23T10:21:07.7866667+00:00

In the ifcfg-eth0

DEVICE=eth0 HWADDR=XXX ONBOOT=yes HOTPLUG=no BOOTPROTO=none TYPE=Ethernet BRIDGE=cloudbr0

In the ifcfg-cloudbr0

DEVICE=cloudbr0 TYPE=Bridge ONBOOT=yes BOOTPROTO=none IPV6INIT=no IPV6_AUTOCONF=no DELAY=5 IPADDR=<NIC DHCP> GATEWAY=<AZURE NETWORK GW> NETMASK=<AZURE NETWORK MASK> STP=yes

The new nested VM inside this host will take this bridge cloudbr0 as the network interface from the KVM network. This means that the CloudStack will create a KVM VM assigning an Azure network IP and network should work.

To summarize, I'm aware that I can have a NIC with multiple IP's from Azure network, but I couldn't find a way to define a network bridge to overlap the Azure default configuration to make this kind of definition.

Thanks
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-24T17:52:11.8366667+00:00

Hi @William TP,

Thanks for getting back.

As these things looks to be non-Microsoft related and whatever configuration which you have done so far needs to be investigated by the third-party KVM.

Create a KVM VM and Cloud stack, this looks like OS level virtualization, so please check with the distros.

Whatever the virtualization you are trying to run, it looks like it needs an investigation by third-party as or to the distros. Kindly let us know if the above helps or you need further assistance on this issue.

Thanks,

Sai Prasanna.
William TP 20 Reputation points

2024-10-25T05:37:58.06+00:00

Hello @Sai Prasanna Sinde ,

Understood. Thanks. Only one doubt about VM and Azure. Which is the way in Azure to make custom changes in the VM networking and persist them? If we edit the network inside it every restarts cloud init reconfigures it. And if we add the "network:" section in cloud init this is ignored.

Thanks
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-28T08:40:13.9566667+00:00

Hi @William TP,

Thanks for getting back.

Please disable the Cloud-Init Networking and manually configure the network interfaces and after making changes, restart the networking service to apply you can also use the Custom Script Extension to run configuration scripts that applies to your networking settings post-deployment.

Kindly let us know if the above helps or you need further assistance on this issue.

Regards,

Sai Prasanna.
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-29T01:43:02.2433333+00:00

Hi @William TP,

Greetings,

I would like to follow up with the thread.

Just checking in to see if you have got a chance to see my response to your question in resolving the issue.

If you are still facing any further issues, please don't hesitate to reach out to us. We are happy to assist you.

Looking forward to your response and appreciate your time on this.

Regards,

Sai Prasanna.
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-30T00:57:50.98+00:00

Hi @William TP,

Greetings,

I would like to follow up with the thread.

Just checking in to see if you have got a chance to see my response to your question in resolving the issue.

If you are still facing any further issues, please don't hesitate to reach out to us. We are happy to assist you.

Looking forward to your response and appreciate your time on this.

Regards,

Sai Prasanna.
William TP 20 Reputation points

2024-10-30T06:08:57.31+00:00

Hi @Sai Prasanna Sinde ,I didn't have the chance to try it, but I'll do when I can. If I've more issues I will ask. In the meantime I think we can close the ticket.

Thanks!
Sai Prasanna Sinde 6,645 Reputation points Microsoft External Staff Moderator

2024-10-30T06:20:58.7533333+00:00

Hi @William TP,

Thanks for the confirmation.

I have converted my comment into an answer.

To close this thread, please click **Accept Answer** and **Yes** for was this answer helpful so that other community members facing the same issue can find the right answers.

And, if you have any further query do let us know. We are pleased to assist you.

Your contribution is highly appreciated.

Regards,

Sai Prasanna.

Answer 1

Hi @William TP,

Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.

Answering your questions,

Whatever network configuration you want to do, please do it by using Azure Portal/PowerShell/CLI, please don't do it with in the OS. You can have multiple IP addresses to a VM but if you want to do it, please make sure you need to configure a guest OS to support it. For your reference: https://learn.microsoft.com/en-us/azure/virtual-machines/linux/multiple-nics#configure-guest-os-for-multiple-nics https://learn.microsoft.com/en-us/azure/virtual-network/ip-services/virtual-network-multiple-ip-addresses-portal#os-config
As these things looks to be non-Microsoft related and whatever configuration which you have done so far needs to be investigated by the third-party KVM.
Create a KVM VM and Cloud stack, this looks like OS level virtualization, so please check with the distros.
Whatever the virtualization you are trying to run, it looks like it needs an investigation by third-party as or to the distros. Kindly let us know if the above helps or you need further assistance on this issue.

Yes. It is possible to have a VM inside a VM. It's called Nested Virtualization.

For your reference: https://azure.microsoft.com/en-us/blog/nested-virtualization-in-azure/

https://learn.microsoft.com/en-us/answers/questions/813416/how-do-i-know-what-size-azure-vm-supports-nested-v
https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/user-guide/enable-nested-virtualization

Please click **Accept Answer** and **Yes** for was this answer helpful so that other community members facing the same issue can find the right answers.

Kindly let us know if the above helps or you need further assistance on this issue.

Thanks,

Sai Prasanna.

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Linux interface networking bride configuration to test KVM nested VM

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