Extra Network Interfaces

Croit makes it easy to configure your physical NICs, bonds, and VLANs. Any other special interface you may need (like a BGP anycast dummy interface) is up to you to create.

Because the croit server images are network-booted and immutable by default, manual terminal changes won't persist after a reboot. You need to create a PostNetworkConfig hook script under Config -> Hook Scripts instead, which also runs automatically on every boot.

Always pin the interface's MAC address in your script. Without a fixed MAC, Linux generates a random one on boot. An unpinned interface looks like a brand-new NIC after every reboot, cluttering your dashboard with stale entries.

#!/bin/bash
set -e
# Create the interface with a fixed MAC address, unless it already exists.
ip link show dummy0 >/dev/null 2>&1 || ip link add dummy0 address 02:00:00:00:00:01 type dummy
ip link set up dev dummy0
# Add the addresses. "replace" keeps the script safe to run again.
ip addr replace 10.0.0.1/32 dev dummy0

Pick the MAC from a locally administered range (the second hex digit is 2, 6, A or E, as in 02:00:00:00:00:01) and give each server its own, so no two nodes share a MAC.

Croit shows these as "Not managed by croit" on the NICs page, but leaves them alone.

Using the loopback interface instead

If you do not need to see the interface in the croit UI, put the addresses on lo instead:

#!/bin/bash
set -e
ip addr replace 10.0.0.1/32 dev lo