LiXS: Lightweight XenStore

LiXS is a C++ implementation of Xen's xenstore server. It focus on performance and efficiency while keeping compatibility with the upstream xenstore protocol.

Motivation

The major goal of LiXS is to provide an efficient and extremely scalable implementation of a xenstore daemon. It scales well to support up to thousands of concurrently running domains while still consuming a low amount of resources. It is therefore suitable to resource constrained devices like recent single board computers.

LiXS was designed to be extensible and configurable. While initialy focusing on creating an upstream xenstore replacement it is intended to be easily extensible in two major aspects:

• Protocol: it should be fairly easy to design and integrate a new version of the xenstore protocol into LiXS.

• Communication channels: it should be straight forward to support new mechanisms to communicate with the xenstore like TCP sockets, shared memory, etc.

Install

Currently LiXS is only available from source so you need to build it first. The process is fairly straightforward though.

Dependencies

To build LiXS you need:

• A modern C++ compiler. Tested and works with clang-3.6 and gcc-4.8, but should be possible to use older versions as far as C++11 is supported.
• Xen and xenstore development headers.

LiXS doesn't really depend on any "non-standard" libraries, besides Xen libs of course. You also need xenstore utilities from upstream to interact with it given LiXS currently doesn't provide any replacement.

Build from source

Building LiXS is fairly straight forward, you basically need:

make

There is a small quirk if you're building for Xen 4.4. On this Xen version the header xenctrl.h uses the GNU C extensions "Incomplete enum Types" that is not supported on C++. Therefore you need to patch this file before building. To do so:

patch -p1 <path_to_xenctrl.h> < extra/xen-4.4-xenctrl.h.patch

The patch basically changes the location of a typedef to appear after the respective enum declaration.

Instalation and configuration

LiXS is comprised of a single binary. To install:

sudo make install

This will basically install app/lixs under /usr/local/sbin/lixs. Finally you need to configure Xen to use this xenstore. For that you must add the following lines to /etc/default/xencommons:

XENSTORED=/usr/local/sbin/lixs
XENSTORED_ARGS="-D --xenbus --unix-socket --virq-dom-exc"

Usage

Under Instal above you basically setup lixs as an upstream xenstore replacement. To configure advance options please read lixs --help.