Since we are installing Ceph on the same Proxmox node, we will set up the network interfaces for a separate network for Ceph traffic only. We will set up three of our example Proxmox nodes—pmx-01, pmx-02, and pmx-03—with Ceph. On all of the three nodes, we will add the following interfaces section to /etc/network/interfaces. You can use any IP address that suits your network environment. We are going to run the following command from the Proxmox node pmx-01:

# nano /etc/network/interfaces

Configure all network interfaces according to IP addresses based on your environment. The following is the content of the network configuration for our example cluster after Proxmox and the Ceph network have been configured:

# Node pmx-01
# Proxmox Network
auto vmbr0
iface vmbr0 inet static
    address 172.16.2.1
    netmask 255.255.252.0
    gateway 172.16.3.254
    bridge_ports ens18
    bridge_stp off
    bridge_fd 0

# Ceph Public Network
auto ens19
 iface ens19 inet static
   address 192.168.20.1
   netmask 255.255.255.0

# Ceph Sync Network
auto ens20
 iface ens20 inet static
 address 192.168.30.1
 netmask 255.255.255.0

The network interfaces can also be configured through Proxmox GUI. Reboot the node or run the following command to make the new interface active:

# ifup eth2

Follow the previous steps and add additional network interfaces with the IP addresses 192.168.10.2 and 192.168.10.3, respectively.