3.1 Libvirt 的 python 模块提供了三种打开连接的方式：
conn = libvirt.open(name)
conn = libvirt.openReadonly(name)
conn = libvirt.openAuth(name, auth, flags)上面三种方式中，参数 name 表示 hypervisor 的 URI 。下面两小节讨论URI格式。
3.2 本地 URI 有四种格式：
driver:///system
driver:///session
driver+unix:///system
driver+unix:///session除了这四种格式，其他格式都是被认为是远程 URI，即使要连接的是本地 hypervisor。
截止2016年，支持的 driver 有以下类型，最常用的当然就是 qemu 了：
| Driver |
Description |
|---|---|
| qemu |
For managing qemu and KVM guests |
| xen |
For managing old-style (Xen 3.1 and older) Xen guests |
| xenapi |
For managing new-style Xen guests |
| uml |
For managing UML guests |
| lxc |
For managing Linux Containers |
| vbox |
For managing VirtualBox guests |
| openvz |
For managing OpenVZ containers |
| esx |
For managing VMware ESX guests |
| one |
For managing OpenNebula guests |
| phyp |
For managing Power Hypervisor guests |
下面做一个打开本地连接的例子，但是请注意权限，我是在 root 下执行的：
# example1.py
# open local connection
# coding: utf-8
from __future__ import print_function
import sys
import libvirt
conn = libvirt.open("qemu:///system")
if conn == None:
print("Failed to connect to qemu:///system", file=sys.stderr)
exit(1)
else:
print("Succeeded to connect to qemu:///system")
conn.close()
exit(0)
3.3 远程URI的格式如下：
driver[+transport]://[username@][hostname][:port]/[path][?extraparameters]各字段的含义如下：
| Component |
Description |
|---|---|
| driver |
The name of the libvirt hypervisor driver to connect to. This is the same as that used in a local URI. Some examples are |
| transport |
The name of one of the data transports described earlier in this section. Possible values include |
| username |
When using the SSH data transport this allows choice of a username that differs from the client's current login name. |
| hostname |
The fully qualified hostname of the remote machine. If using TLS with x509 certificates, or SASL with the GSSAPI/Keberos plug-in, it is critical that this hostname match the hostname used in the server's x509 certificates / Kerberos principle. Mis-matched hostnames will guarantee authentication failures. |
| port |
Rarely needed, unless SSH or libvirtd has been configured to run on a non-standard TCP port. Defaults to |
| path |
The path should be the same path used for the hypervisor driver's local URIs. For Xen, this is always just |
| extraparameters |
The URI query parameters provide the mean to fine tune some aspects of the remote connection, and are discussed in depth in the next section. |
根据上面的表格，举几个远程 URI 的例子：
# Connect to a remote Xen hypervisor on host node.example.com using ssh tunneled data transport and ssh username root:
xen+ssh://[email protected]/
# Connect to a remote QEMU hypervisor on host node.example.com using TLS with x509 certificates:
qemu://node.example.com/system
# Connect to a remote Xen hypervisor on host node.example.com using TLS, skipping verification of the server's x509 certificate (NB: this is compromising your security):
xen://node.example.com/?no_verify=1
# Connect to the local QEMU instances over a non-standard Unix socket (the full path to the Unix socket is supplied explicitly in this case):
qemu+unix:///system?socket=/opt/libvirt/run/libvirt/libvirt-sock
# Connect to a libvirtd daemon offering unencrypted TCP/IP connections on an alternative TCP port 5000 and use the test driver with default configuration:
test+tcp://node.example.com:5000/default同样，写一个远程连接的例子， 这里使用了 ssh 认证的方式 ：
# coding: utf-8
from __future__ import print_function
import sys
import libvirt
conn = libvirt.open('qemu+ssh://host2/system')
if conn == None:
print('Failed to open connection to qemu+ssh://host2/system', file=sys.stderr)
exit(1)
else:
print('Succeeded to open connection to qemu+ssh://host2/system')
conn.close()
exit(0)