Proxmox 5.3, DHCP for vmbr0

[tommoyer]

I've done a fresh install of Proxmox 5.3 and in my network setup, static IPs are difficult to setup and the recommended solution from my network admins is to use DHCP for everything, and setup DNS entries dynamically when clients connect, based on the hostname the client provides in the DHCP discover.

Given that setup, I am trying to reconfigure Proxmox to use DHCP for the vmbr0 interface that is created by default but after I make the appropriate changes in /etc/network/interfaces, when I reboot, none of the Proxmox services start and I see an error about a missing SSL key (/etc/pve/local/pve-ssl.key) for all of the services.

Is there an easy way to allow vmbr0 to obtain an IP via an external DHCP server and ensure that all the Proxmox services start correctly?

 

[t.lamprecht]

You also need to ensure the IP stays static, i.e., your DHCP server reserves it for your nodes (hostname or MAC), at best you set it to the same you initially configured for it when it was static, then a simple

auto vmbr0
iface vmbr0 inet dhcp
        bridge_ports eth0
        bridge_stp off
        bridge_fd 0

in network/interfaces should do it. If the IP changes you always need to ensure that at least the entries in /etc/hosts changes too, and in a cluster this will bring you only problems. So DHCP can work, as long as it's setup to be completely static regarding PVE nodes...

 

[sshaikh]

For anyone else who finds this, don't do what I did and replace everything vmbr0 with the above. You'll lose network access. Make sure you keep the bridge lines, so perhaps something like:

auto vmbr0
iface vmbr0 inet dhcp
        bridge_ports eth0
        bridge_stp off
        bridge_fd 0

Reference: https://forum.proxmox.com/threads/problems-with-network-configuration.23552/post-117917

 

[t.lamprecht]

Sure, I only meant to replace the first two lines, but thanks for clarifying - I edited my original post to avoid further confusion.