用C++编程调用libvirt的API来创建KVM虚拟机

1. 如果已经写好了创建kvm的配置文件（stand.xml）格式，那么创建kvm虚拟机只要使用命令即可：

virsh define ./conf/stand.xml                                                                                                                                  virsh start rheltest3

2. 如果直接编程调用libvirt创建kvm虚拟机，则可用以下程序

/*************************************************************************** * create_vm.cpp  *  create kvm machine(domain) based on conf.xml *  the first parameter is the conf xml files' name *  Note: the .xml must has two boot types (cdrom/hd) by any order *  compile command: 'g++ create_vm.cpp -o createvm -lvirt' *  running command: './createvm  /path/to/xml/example.xml' *  author  : Aborn Jiang *  date    : Aug.17, 2013 *  version : v0.1 ***************************************************************************/#include <iostream>#include <cstdio>#include <string>#include <fstream>#include <sstream>#include <libvirt/libvirt.h>#include <libvirt/virterror.h>#include <memory.h>using namespace std;int main(int argc, char* argv[]){if ( 1 == argc ) {cout << "must and only need an argument, this is, configure .xml file name." << endl;return -1;} if ( 3 <= argc ) {cout << "too many arguments. must and only need one, that is, .xml file name." << endl;return -1;}string xmlfile=argv[1];cout << "*************************" << endl;cout << "begin to build vm ..." << endl;cout << "xmlfile path:" << xmlfile <<endl;ifstream file(xmlfile.c_str());if (!file) {cout << "Cannot open file, permission denied." << xmlfile << endl;return -1;}stringstream buffer;buffer << file.rdbuf();string xmlcontents = buffer.str();file.close();/*************************************************************************************  * deal with the original xml configuration file * initxmlconts for transient guest domain(install os) configure (boot from cdrom) * xmlcontents  for persistent guest domain configure (boot from hd) ************************************************************************************/int pos_boot  = xmlcontents.find("boot");int pos_hd    = xmlcontents.find("hd", pos_boot);int pos_cdrom = xmlcontents.find("cdrom", pos_boot);cout << "pos_hd=" << pos_hd << "  pos_cdrom=" << pos_cdrom << endl;string initxmlconts(xmlcontents);if ( pos_hd > pos_cdrom ) {    // cdrom apears in first ordercout << "cdrom apears in first order" << endl;xmlcontents.replace(pos_cdrom, 5 ,"hd");pos_hd=xmlcontents.find("hd", pos_cdrom + 2);xmlcontents.replace(pos_hd, 2, "cdrom");} else {                     // hd apears in first ordercout << "hd apears in first order" << endl;initxmlconts.replace(pos_hd, 2, "cdrom");pos_cdrom=initxmlconts.find("cdrom", pos_hd + 5);initxmlconts.replace(pos_cdrom, 5, "hd");}// create and boot a transient initial domain, for vm os installationvirConnectPtr conn = virConnectOpen("qemu:///system");if (NULL == conn ) {virErrorPtr error = virGetLastError();cout << error->message << endl;return -1;}virDomainPtr vmpi = virDomainCreateXML(conn, initxmlconts.c_str(), VIR_DOMAIN_START_AUTODESTROY);if (NULL == vmpi) {virErrorPtr error = virGetLastError();cout << error->message << endl;return -1;}cout << "os installation ongoing, it will spend some time..." << endl;while ( 1 == virDomainIsActive(vmpi) );                // waiting until installation finish.cout << "os installation finished..." << endl;if (NULL == conn)virConnectPtr conn = virConnectOpen("qemu:///system");cout << "start boot the vm machine..." << endl;// store xmlcontents configuration for a persistent guest domain and boot it.virDomainPtr vmp = virDomainDefineXML(conn, xmlcontents.c_str());if (NULL == vmp) {virErrorPtr error = virGetLastError();cout << error->message << endl;return -1;} else {cout << "define persistent domain success." << endl;if (virDomainCreate(vmp) < 0) {                   // boot the vm.cout << "Unable to boot guest configuration." << endl;} else {cout << "Boot the persistent defined guest ..." << endl;}cout << "build vm finished." << endl;cout << "*************************" << endl;return 0;}}

3. 附stand.xml文件内容

<domain type='kvm'><name>rheltest3</name><uuid>32b95fab-6d78-4e28-beca-2d3988ff8c8f</uuid><memory unit='KiB'>1048576</memory><currentMemory unit='KiB'>1048576</currentMemory><vcpu placement='static'>1</vcpu><os><type arch='x86_64' machine='pc-1.2'>hvm</type><boot dev='hd'/><boot dev='cdrom'/></os><features><acpi/><apic/><pae/></features><clock offset='utc'/><on_poweroff>destroy</on_poweroff><on_reboot>restart</on_reboot><on_crash>restart</on_crash><devices><emulator>/usr/bin/qemu</emulator><disk type='file' device='disk'><driver name='qemu' type='qcow2'/><source file='/home/lisp/code/auto-rhel/virt/rheltest3.img'/><target dev='hda' bus='ide'/><address type='drive' controller='0' buss='0' target='0' unit='0'/></disk><disk type='file' device='cdrom'><driver name='qemu' type='raw'/><source file='/home/lisp/code/auto-rhel/rhelcustom.iso'/><target dev='hdc' bus='ide'/><readonly/></disk><controller type='usb' index='0'><address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/></controller><controller type='ide' index='0'><address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/></controller><interface type='bridge'><mac address='52:54:00:78:f9:98'/><source bridge='virbr0'/><model type='virtio'/><address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/></interface><input type='mouse' bus='ps2'/><graphics type='vnc' port='-1' autoprot='yes'/><memballoon model='virtio'><address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/></memballoon></devices></domain>