Proxmox Node IP Address Change with Ceph

Overview

This guide explains how to change a Proxmox node’s IP address, including updates to networking, Corosync, and Ceph configuration, all in one process.

In this example, the IP addresses are being changed from the 10.10.20.0/24 subnet to the 10.10.0.0/24 subnet.

Step 1: Update Network Configuration

Edit the network interfaces file to set the new IP address and gateway:

nano /etc/network/interfaces

Edit the hosts file and update any entries with the new IP:

nano /etc/hosts

Change the DNS server if needed:

nano /etc/resolv.conf

Step 2: Update Corosync Configuration

Update the Corosync config file and replace only the IP address of the current node:

nano /etc/pve/corosync.conf

Step 3: Update Known Hosts (if Master Node IP is Changing)

If you are changing the master node’s IP address, update:

nano /etc/pve/priv/known_hosts

Insert the new IP of the master node.

Step 4: Update Ceph Configuration (If Using Ceph)

Edit the Ceph configuration to reflect the new networks:

nano /etc/ceph/ceph.conf

Modify these lines:

cluster_network = 10.10.20.0/24,10.10.0.0/24
public_network  = 10.10.20.0/24,10.10.0.0/24

Step 5: Reboot the Node

Reboot to apply network and service changes:

reboot

Step 6: Remove Old Monitor (MON) via GUI

In the Proxmox web interface, delete the MON of the node you changed.

Step 7: Temporarily Edit ceph.conf Again

Before recreating the MON, temporarily restrict public_network:

nano /etc/pve/ceph.conf

Modify:

public_network = 10.10.0.0/24

Step 8: Create the New Monitor (MON)

Use the following command:

pveceph mon create

Step 9: Restore Original ceph.conf

Edit ceph.conf again:

nano /etc/pve/ceph.conf

Restore:

public_network = 10.10.20.0/24,10.10.0.0/24

Make sure the [mon.<hostname>] section contains:

[mon.work]
public_addr = 10.10.0.12

Replace work and 10.10.0.12 with your actual hostname and new IP.

Repeat for Other Nodes

Repeat the whole process on any additional nodes (e.g. 3 total).

After completing the change on the last node, you can simplify the network configuration to only:

public_network  = 10.10.0.0/24
cluster_network = 10.10.0.0/24

 Final Reboot

Reboot the final node:

reboot