No communication between two VMs connected to the same VLAN - OpenShift Virtualization

[ark1984]

Dear All,

I am using OpenShift virtulization to run 2 x Windows VMs and 2 x Fedora VMs. All these VMs are connected to a VLAN subinterface configured on a linux bridge.  I used NNCP and NAD create the bridge and subinterfaces. All VMs are able to communicate outside (like google, 8.8.8.8). I can reach all VMs from my external network.  But they cannot ping each other. Firewalls are disabled on all VMs

[Wasim_Raja]

@ark1984 Thanks for reaching out.

The below doc can be handy.

https://www.redhat.com/en/blog/connecting-to-vms-in-red-hat-openshift-virtualization

Let me know if it helps you.

[ark1984]

Hello Wasim,

I have used the same article and connected my VMs to NAD with VLANs on linux bridge (defined using NNCP). Those VMs can reach external services without any issues and I can reach those VMs from external network. 

The problem is that they cann't ping to each other even if they are on the same worker node. 

[Chetan_Tiwary_]

@ark1984  what does the tcpdump see - where is it getting dropped ?

[ark1984]

Hi @Chetan_Tiwary_ ,

I am running this on a VMware setup to test it out. 

I captured the packets it show arp request is getting timed out. I done the capture on the vNIC of the VMs where I am running the nested VM inside it. 

This is what i have done: 

1. Configured the NNCP to enable the second interface on the and create a bridge using it. I name the bridge wl-br01. 
2. Then I used NAD define linux bride with VLAN associated. 

VMs are getting IP address from an external DHCP server and able to reach the internet destinations as well. But they can't reach each other. 

[ark1984]

Hi @Chetan_Tiwary_  @Wasim_Raja ,

I have tried the configuration with OVS-Bridge. And now the communication is okay betweem VMs and externally. Still unable to identify why linux bridge doesn't work. 

[ark1984]

Please, can anyone provide an insight here? 

[Wasim_Raja]

@ark1984 Thanks for reaching out.

The below doc can be handy.

https://www.redhat.com/en/blog/connecting-to-vms-in-red-hat-openshift-virtualization

Let me know if it helps you.