Multi-hosted IP Addresses with Zeus Software

One of the new features in Zeus 6.0 is the ability for traffic managers in a cluster to share an IP address, and have its incoming connections evenly processed by each machine. This article explains how to get the Linux kernel module required for it to work.

The following only applies to customers and evaluators running Zeus 6.0 or later on a supported Linux system (kernels 2.6.8.1 to 2.6.31). The multi-hosted IP kernel module is already included with Zeus Appliances (both physical and virtual).

Why use the Multi-hosted IP module?

The multi-hosted IP module shares the incoming data for an IP address across multiple hosts in a cluster. This means that you do not need an IP address for each machine in the cluster (like when using normal, single-hosted traffic IPs), thus reducing the amount of public IP addresses you need.

It also has the advantage that load is distributed evenly across every active machine, even when some machines have failed. Single-hosted traffic IPs often end up with an un-even distribution of load when failure occurs, as an entire IPs load is transferred to a single machine when the original host fails.

Obtaining the Multi-hosted IP module

Configuration

Configuration of the module is completely handled by the Zeus software. You will need to configure your Traffic IP groups to use multi-hosted mode, and give them a valid multicast address to share traffic with. See the User Manual for full details.

Switch Compatibility Issues

The multi-hosted IP module makes a unicast IP address act like a multicast address. This can cause issues with some switches, and thus they may require additional configuration in order for multi-hosted IPs to work correctly. See the FAQ article Why can't users connect to my Multi-host IPs.

Changes

2.1 - 13th January 2010

• Support kernels 2.6.8 -> 2.6.31

2.0 - 19th October 2009

• Initial release with 'zcluster' support
• Support kernels 2.6.8 -> 2.6.28

Matt H [Zeus Dev Team] 19 October 2009 1 comment