Proxmox says my bridge is up but the VM's claim the network interface tied to the bridge is down. What did i screw up?

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anderstn

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Dec 22, 2020
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Hi
I recently installed a new 10gb nic in my server and wanted to run all VM's through it and keep the onboard interface for the proxmox web-ui only. To do this I added a new bridge and tied the VirtIO adapters my virtual machines were using to this new bridge. Proxmox says the bridge is up, the switch says tehre is a link, but all the VM's claim the interface is down. What did I do wrong?

Proxmox configuration:
1680215092476.png

The interface attached to one of my VM's:
1680215148826.png
The output from "nmcli device status" inside the VM (running Centos):
1680215197216.png
Verified that this is the correct interface:
1680215316215.png
 
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HI,
according to the nmcli output you posted there is a connection available. Have you tried to bring the connection up by running nmcli con up ens18, which will try to connect using the best available connection for that interface.
 
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Chris said:
HI,
according to the nmcli output you posted there is a connection available. Have you tried to bring the connection up by running nmcli con up ens18, which will try to connect using the best available connection for that interface.
Click to expand...
I'll give it a go when I get back home, but I think the system tried to bring up the connection before it went down. As I am new to virtual switches is it common if a connection is available but no IP is forthcoming via DHCP for the client, in this case CentOS, to essentially list a VirtIO adapter as down?
 
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anderstn said:
I'll give it a go when I get back home, but I think the system tried to bring up the connection before it went down. As I am new to virtual switches is it common if a connection is available but no IP is forthcoming via DHCP for the client, in this case CentOS, to essentially list a VirtIO adapter as down?
Click to expand...
If there is no DHCP server you will have to manually configure an IP address, yes. For how to do that with nmcli, i assume the redhat docs are a good reference, see https://access.redhat.com/documenta...uide/sec-configuring_ip_networking_with_nmcli
Otherwise you can use nmtui if available, which allows for a more interactive setup.
 
Chris said:
If there is no DHCP server you will have to manually configure an IP address, yes. For how to do that with nmcli, i assume the redhat docs are a good reference, see https://access.redhat.com/documenta...uide/sec-configuring_ip_networking_with_nmcli
Otherwise you can use nmtui if available, which allows for a more interactive setup.
Click to expand...
There is DHCP on the network. It works just fine through vmbr0 which is connected to the same switch via the 1gb nic integrated on the motherboard. That said if setting a static IP forces the interface to be up I can always try that as well =)
 
anderstn said:
There is DHCP on the network. It works just fine through vmbr0 which is connected to the same switch via the 1gb nic integrated on the motherboard. That said if setting a static IP forces the interface to be up I can always try that as well =)
Click to expand...
Well, setting a static IP will not "force" it to be active, you still need to bring up the interface in that case ;).
For a correct dhcp setup using nmcli, see https://access.redhat.com/documenta...sec-comparing_static_to_dynamic_ip_addressing
 
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