Changing IP on Proxmox 6 with bonds and bridges

Posted on
proxmox tech

I am running Proxmox 6 as my virtualization server, an HP Proliant DL380 G6.
It is working just fine, apart from that RAID card… and I still haven’t figured out how use go around it to using ZFS… but that is another discussion.

I am restructuring my network to make it more logical and neat.
I save the best for last, my VM server.

Hardware-wise the server has 4 NIC’s, five to be exact but the last is for ILO.

So inside Proxmox all 4 is discovered, and I have created two bond, with two NIC’s each and ontop of that two vmbtidges.

So now you know were I stood this morning (lets just say it is not morning any longer..).

I jumped around on the net before doing anything, but what do you know it didn’t make me any wiser, so I took the bull by the horns and started to try to wrestle it, as you might guess and can see on both the Proxmox forums and Reddit it failed.
What I did was to ssh to the server, edit the hosts file and interfaces file and rebooted.
Then the service that handles the webgui didn’t start… the IPs worked just fine but not the server so to say.

After hours of trying to fix it, with the help of fellow reddit ppl I gave up and redo what I just made, rebooted the machine and voila, it worked again.

Sigh. What the. This is what happened when I tried to edit the IP in the gui.

interface ‘vmbr1’ - mtu 1500 is lower than ‘bond1’ - mtu 9000 (500)

This I fixed by removing the mtu settings in the interfaces file so then I was able to remove one bridge, and when I try to add a new one, this error:
Parameter verification failed. (400)gateway: Default gateway already exists on interface ‘vmbr0’

Say what? I cannot add a gateway on the second bridge? How what… I did have the gateway on both bridges earlier and now I can’t?

Oh well that was a relic from Proxmox 5 so well ok…

Now I was able to remove one bridge and reconfigure it with it’s new IP and all, rebooted to activate it and accessed to gui from that bridge to redo the other one and reboot.

Now the server is up on the new IPs and I have just added the itu setting in the interface file again.

Lets hope I can help someone else how to do this or am I just showing how stupid I am, because I felt kinda stupid all day to be honest.