Building Xenopsd

Xenopsd is the "domain management" component within the XCP toolstack.

Prerequisites

You will need:

1. the normal build tools (on Debian install "build-essential git rsync wget")
2. the Xen development headers (on Debian install "libxen-dev")
3. the OCaml compiler (at least version 3.12.1)
4. the OCaml package manager, OPAM

Assuming a Debian wheezy system (other systems may differ), first install the system packages:

 $ sudo apt-get install build-essential git rsync wget libxen-dev ocaml

Then install the OPAM tool:

 $ wget http://github.com/OCamlPro/opam/archive/0.8.2.tar.gz
 $ tar -xvzf 0.8.2.tar.gz
 $ cd opam-0.8.2
 $ ./configure
 $ make
 $ sudo make install

NB the current release fails to build because it tries to download a dependency from a broken URL: https://github.com/OCamlPro/opam/issues/356

Next initialise OPAM, this will read in the definitions of common OCaml packages.

 $ opam init

Since OPAM packages are installed by default into a custom directory in $HOME/.opam, it's necessary to update some paths. The instructions will be printed to your terminal and typically look like the following:

To update $PATH, $MANPATH, $OCAML_TOPLEVEL_PATH, $CAML_LD_LIBRARY_PATH; you can now run:
           
   $ which opam && eval `opam config -env`

and add this in your ~/.profile

Building xenopsd (and associated tools)

To make building easy, the development versions of xenopsd (and associated tools) are packaged into OPAM packages in a custom repository. To build, first add this repository as a remote:

 $ opam remote -add xen-dev git://github.com/xen-org/opam-repo-dev

The new packages found in this remote will be listed on your terminal and may be queried via "opam list". At the time of writing this list looked like:

The following NEW packages are available:
- fd-send-recv.1.0.0
- forkexecd.1.0.0
- message_switch.1.0.0
- shared-memory-ring.1.0.0
- xcp.1.0.0
- xen-api-client.1.0.0
- xenctrl.4.1.0
- xenops-cli.1.0.0
- xenopsd.1.0.0
- xenstore.2.0.0
- xenstore_transport.1.0.0

Finally, to build xenopsd (and its CLI) and all their dependencies, use the following command:

 $ opam install xenopsd xenops-cli

The xenospd binary will end up in .opam/system/bin and should be on your $PATH (if you followed the earlier instructions to update your environment)

Running xenopsd

The build process also creates a basic configuration file. It can be started using:

 $ sudo ./.opam/system/bin/xenopsd -config ./.opam/system/etc/xenopsd.conf

by default it will not daemonize and continue writing debug messages to the terminal.

To read the CLI help, try:

 $ xenops-cli
 $ xenops-cli add --help

Starting a simple VM

The xenops-cli is able to read and write VM config files in xm/xl syntax. First create a file with contents like: