FreeBSD CARP Lab

Overview

Join us for a hands-on workshop exploring high availability (HA) at the router level and blue/green deployment strategies using shared IP addresses.

We'll focus on FreeBSD's built-in HA support via the Common Address Redundancy Protocol (CARP) and test it with GRE tunnels and OVH IPFO setups.

Goals

• Provide HA at the router level
• Enable smooth blue/green deployment with a shared IP address
• Explore strategies for integrating CARP with our network setup

Context

The Nasqueron Operations SIG is considering to create several router servers for their network. The idea is to allow easy OS updates without disrupting traffic while maintaining HA.

While we initially thought about creating a custom solution (like Keepalived) with scripts for virtual IP and MAC address management, FreeBSD offers CARP out of the box. CARP allows multiple hosts on the same network to share IPv4/IPv6 addresses, taking over almost instantly if one server fails (down to ~4 ms delay).

What we'll do

1. Pick two FreeBSD machines for the setup
2. Enable CARP on all machines
3. Configure CARP for the main gateway
4. Configure CARP for GRE tunnels
5. Test FreeBSD bug [[1]] (optional)
   1. Install Quagga
   2. Configure OSPF
   3. Run `ospfd`
6. Verify CARP works with OVH IPFO and links the IPFO to the virtual MAC address
7. Handle CARP status change events with devd rules
8. Brainstorm and document best strategies for blue/green deployment

Special Notes

• FreeBSD Bug 166462:* This bug was reported before the FreeBSD 10 CARP rewrite. Testing it usually requires a full GRE + OSPF + IPsec setup, but our environment may allow us to reproduce it easily.

• OVH IPFO Considerations:* OVH routes traffic for an IPFO to a known MAC attached to a specific server. This means we need to generate a dedicated MAC at the OVH level for the virtual interface.

References

• CARP manual
• FreeBSD and OSPFd
• Quagga OSPF Documentation

Who should attend

Network enthusiasts, FreeBSD users, and anyone interested in high availability and advanced deployment strategies. Prior networking experience is recommended.

Logistics

This workshop is part of a Nasqueron lab x Wolfplex labworkshop series. Bring your laptop if you want to participate actively, or observe and learn from the setup.

Plan is do that workshop both in a physical location and online.