编译和安装

  1、（1）准备好libvirt-1.3.5安装包，用MobaXterm工具将准备好的libvirt上传到/usr/local/目录下

    （2）将libvirt-1.3.5.tar解压到/usr/local/目录下

         cd /usr/local/

         tar -zxf libvirt-1.3.5.tar.gz

  2、配置libvirt

    (1)配置libvirt时，需运行libvirt目录下的configure脚本文件。

        进入libvirt解压目录下

        cd libvirt-1.3.5

        [root@localhost libvirt-1.3.5]#./configure

  3、编译libvirt

    (1)配置。/configure成功后，在libvirt安装目录下执行“make”命令编译。

       cd libvirt-1.3.5

       [root@localhost libvirt-1.3.5]#make

  4、安装libvirt，libvirt 安装会默认安装libvirtd和virsh等可执行程序。

     (1)编译完成后执行“make install”安装libvirt

[root@localhost libvirt-1.3.5]# make install

     (2)查看libvirtd位置命令：

[root@localhost libvirt-1.3.5]# which libvirtd

     (3)查看libvirtd版本号：libvirtd -version

      (4) 查看virsh位置命令：

           [root@localhost libvirt-1.3.5]# which virsh

       (5)查看virsh版本号:

         [root@localhost libvirt-1.3.5]# virsh -version

      (6)查看libvirtd和virsh的头文件和库文件：

         [root@localhost libvirt-1.3.5]# ls /usr/local/include/libvirt

        [root@localhost libvirt-1.3.5]# ls /usr/local/lib/libvirt*

   5、查看已经安装的libvirt

      查看libvirt是否启动，实质是查看libvirt的libvirtd这个守护进程是否启动。

      (1) [root@localhost libvirt-1.3.5]# ps -le |grep libvirtd

      (2)启动libvirt

[root@localhost libvirt-1.3.5]# service libvirtd start

[root@localhost libvirt-1.3.5]# service libvirtd status

• libvirt的配置文件

    1、libvirt文件配置

（1）libvirt的配置文件一般在/etc/libvirt/目录下

       [root@localhost ~]# cd /etc/libvirt

       [root@localhost libvirt]# ls

    2、libvirt中域的XML配置文件格式

 <domain type='kvm'>

     <!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->

     <name>libvirt</name>

     <uuid>32b95fab-6d78-4e28-beca-2d3988ff8c8e</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/local/bin/qemu-system-x86_64</emulator>

      <!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->

      <disk type='file' device='disk'>

        <driver name='qemu' type='qcow2'/>

        <source file='/tmp/ubuntu.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='/tmp/ubuntu-18.04.5-desktop-amd64.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>

    3、libvirt API使用示例

      (1)[root@localhost qemu]#virsh create /etc/libvirt/qemu/demo.xml

         [root@localhost qemu]#virsh -c qemu:///session

     (2)使用API查询某个域的信息，C语言示例如下：

      #include<stdio.h>

#include<stdlib.h>

#include<libvirt/libvirt.h>

virConnectPtr conn=NULL;

virConnectPtr getConn()

{

          conn=virConnectOpenReadOnly(NULL);

          if(conn==NULL)

          {

             printf("error,cann't connect!");

             exit(1);

           }

           return conn;

}

int getInfo(int id)

{

          virDomainPtr dom=NULL;

          virDomainInfo info;

          conn=getConn();

          dom=virDomainLookupByID(conn,id);

          if(dom==NULL)

          {

             printf("error,cann't find domain!'");

             virConnectClose(conn);

             exit(1);

           }

          if (virDomainGetInfo(dom,&info)<0)

          {

              printf("error,cann't get info!");

              virDomainFree(dom);

              exit(1);

           }

           printf("the Domain state is:%c\n",info.state);

           printf("the Domain allowed max memory is:%ld KB\n",info.maxMem);

           printf("the Domain used memory is:%ld KB\n",info.memory);

           printf("the Domain vCPU number is:%d\n",info.nrVirtCpu);

           if(dom!=NULL)

           {

             virDomainFree(dom);

           }

           if(conn!=NULL)

          {

             virConnectClose(conn);

           }

          return 0;

}

int main()

{

          getInfo(1);

          return 0;

}

    (3)编译运行libvirt-conn.c并使用virsh查看当前节点情况

      [root@localhost ~]#virsh

virsh#define /etc/libvirt/qemu/demo.xml

virsh#start libvirt

virsh#list

    [root@localhost qemu]#ln -s /usr/local/var/run/libvirt /var/run/libvirt

    virsh#domname1

virsh#dominfo 1

       virsh#list

       [root@localhost ~]#vncviewer 172.0.0.1:0

问题解决：

一、问题：

   1、问题一：configure: error: You must install the libyajl library & headers to compile libvirt

       解决方案：yum install yajl-devel

2、问题：You must install the pciaccess module to build with udev

    解决方案：yum install libpciaccess-devel

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

   解决方案：yum install device-mapper-devel

4、出现问题：checking libxml2 xml2-config >= 2.6.0 ... configure: error: Could not find libxml2 anywhere (see config.log for details).

解决方案：yum install libxml2-devel

5、问题：configure: error: libnl-devel >= 1.1 is required for macvtap support
解决方案： yum -y install libnl-devel

6、问题：启动Libvirt出现问题：libvirtd: error: Unable to obtain pidfile. Check /var/log/messages or run without --daemon for more

解决方案：

（1）查找到libvirtd.pid文件，根据libvirt的安装不同，位置可能不同：

$ sudo find / -name libvirtd.pid

[sudo] password for cloud:

/usr/local/var/run/libvirtd.pid

（2）删除：$sudo rm /usr/local/var/run/libvirtd.pid

（3）启动：$sudo libvirtd -d