Accessing XCP through libvirt API

Libvirt has enhanced its accesability to XCP or XenServer via its API. Inorder to use this feature you must compile libvirt from source with this feature enables. below are the steps to compile libvirt and its dependencies.

Step 1: There are two modes of accessing XCP via libvirt.
            * From the same machine where XCP is installed
            * On a remote machine

            But i would advice you to install libvirt on the same machine where XCP is installed as some native codes might require direct or local access.

Now,

Log in to the machine where you want to install libvirt.

Step 2: First you need to download and install xenapi package. Download xenapi package (libxenserver) from the following URL

ftp://193.166.3.2/pub/NetBSD/packages/distfiles/libxenserver-5.6.100-1-src.tar.bz2

Step 3: Open a terminal and extract the source

# cd <directory where it is downloaded>
# tar jxvf libxenserver-5.6.100-1-src.tar.bz2
# cd libxenserver

Step 4: Compile libxenserver. To compile you must have installed the following dependencies

* libxml2-dev
* libcurl3-dev
* zlib1g

in a debian/ubuntu based machine you can install like this

# apt-get install libxml2-dev
# apt-get install libcurl3-dev
# apt-get install zlib1g

There is a small change you have to make in the 'Makefile'

# vi Makefile

find the line (line no: 65)

$(TEST_PROGRAMS): test/%: test/%.o libxenserver.so
        $(CC) $(LDFLAGS) -o $@ $< -L . -lxenserver

and replace it as

$(TEST_PROGRAMS): test/%: test/%.o libxenserver.so
        $(CC) -o $@ $< -L . -lxenserver $(LDFLAGS)

Also find (line no: 73)


$(INSTALL_PROG) libxenserver.so.$(MAJOR).$(MINOR) $(DESTDIR)/usr/$(LIBDIR)

replace with

$(INSTALL_DATA) libxenserver.so.$(MAJOR).$(MINOR) $(DESTDIR)/usr/$(LIBDIR)

and then compile

# make LIBDIR=lib/
# ar rcs libxenserver.a
# make install LIBDIR=lib/

Step 5: Download libvirt from

http://libvirt.org/sources/libvirt-0.10.2.tar.gz

Step 6: Configure and compile libvirt

# cd <directory where it is downloaded>
# tar zxvf libvirt-0.10.2.tar.gz
# cd libvirt-0.10.2
# ./configure --with-esx --with-xenapi=<path to libxenserver that you installed earlier>  --prefix=/opt/libvirt

Here --prefix=/opt/libvirt is optional if you dont want it to install in system folders like /usr /bin ,etc

At the end of the above step, we must be able to identify that if libxenserver is included or not, from the output

NOTE:

1. While configuring if you find some errors that some package is missing, then install that package and reconfigure again.

eg:

configure: error: You must install device-mapper-devel/libdevmapper >= 1.0.0 to compile libvirt

Here you must install the package

libdevmapper-dev

Installation always require a development version, even though if it does not point it

2. Even though we have already installed libxenserver, sometimes the compiler cannot find LINK to libxenserver files

you can try the following solutions

# ldconfig

If this does not work, change the following code in "configure" file

# vi configure

Search for the line

        LIBXENSERVER_LIBS="$LIBXENSERVER_LIBS -lxenserver"

Scroll below to find "else" part like this

        if test "$with_xenapi" = "yes"; then
            fail=1
        fi
            with_xenapi=no

Replace it with

        with_xenapi=yes

        LIBXENSERVER_LIBS="$LIBXENSERVER_LIBS -lxenserver"

And then run the above command again.

Next to compile,

# make
# make install

You can also check the api capabilities with respect to xenapi from the following URL.

http://libvirt.org/hvsupport.html

This concludes our step by step installation of libvirt with xenapi support. :)