[SOLVED] request help changing main Ethernet port

R

ReenigneArcher

Member
Mar 20, 2022
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My proxmox host has 2 ethernet ports on the motherboard.

I have been using eth0, but since 2 days ago it seems the port is dead (I think there was power surge that killed it). It no longer lights up at all, though it may not be completely dead as my Plex vm was still working until I tried rebooting the Proxmox server. I couldn't access any web gui's on my proxmox host (proxmox itself or from any services on my VMs, other than Plex).

I'd like to switch it over to eth1, but not having much luck. I thought changing the bridge on `iface vmbr0` to `eth1` in `/etc/network/interfaces` and restarting would be enough, but sadly the host still doesn't have network. Any ideas what I am missing?
 
Hey,

yes, changing the bridge-ports of vmbr0 and ifreload -a is enough. But "only one VM reachable" is not a thing that happens if the NIC is fried. Could you post the output of cat /etc/network/interfaces and ip a? Also, does ifreload -avvv exit with 0? Does it show any warnings/errors?
 
I don't know why, but the Plex VM often stays connected even when proxmox itself has no connection anymore. Maybe because it's a Windows VM?

`ifreload -avvv` exits with code 1

I'm having difficulty seeing the full output due to the default resolution. I will look up how to change that and report back.
 
So, I decided to try something.

Instead of just rebooting, I physically unplugged the power cable from the host for about a minute. After reconnecting eth0 started to have an active link again and it seems everything is working.

Edit: It would be nice if I didn't have to always use the same ethernet port (since they are not labeled). I don't know if there's a way to allow eth0 or eth1 in the vmbr0. Other than that, all good.
 
Last edited:
Hey,

you can create an active-backup bond[1], there are different types of bonds but for this active-backup is what you want. It'll basically use the other if one is not working. Config is pretty straight forward and looks something like this
Code: 
auto bond0
iface bond0 inet manual
    bond-slaves eth1 eth2
    bond-mode active-backup
      
auto vmbr0
iface vmbr0 inet static
    ...
    bridge-ports bond0
    ...
so just use the created bond0 as port on the vmbr0


`ifreload -avvv` exits with code 1
Click to expand...
that is not very good, and should be checked out. This usually points to something being off in /etc/network/interfaces. You can use
Code: 
ifreload -avvv > $(hostname)_ifreload.txt 2>&1
and then
Code: 
less $(hostname)_ifreload.txt
like this you can scroll through the output.

[1] https://pve.proxmox.com/wiki/Network_Configuration#sysadmin_network_bond
 
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