<html><body>
<h1>VMware ESX hypervisor driver</h1>
<ul id="toc"></ul>
<p>
The libvirt VMware ESX driver can manage VMware ESX/ESXi 3.5/4.x and
VMware GSX 2.0, also called VMware Server 2.0, and possibly later
versions. <span class="since">Since 0.8.3</span> the driver can also
connect to a VMware vCenter 2.5/4.x (VPX).
</p>
<h2><a name="project">Project Links</a></h2>
<ul>
<li>
The <a href="http://www.vmware.com/">VMware ESX and GSX</a>
hypervisors
</li>
</ul>
<h2><a name="prereq">Deployment pre-requisites</a></h2>
<p>
None. Any out-of-the-box installation of VPX/ESX(i)/GSX should work. No
preparations are required on the server side, no libvirtd must be
installed on the ESX server. The driver uses version 2.5 of the remote,
SOAP based
<a href="http://www.vmware.com/support/developer/vc-sdk/visdk25pubs/ReferenceGuide/">
VMware Virtual Infrastructure API</a> (VI API) to communicate with the
ESX server, like the VMware Virtual Infrastructure Client (VI client)
does. Since version 4.0 this API is called
<a href="http://www.vmware.com/support/developer/vc-sdk/visdk400pubs/ReferenceGuide/">
VMware vSphere API</a>.
</p>
<h2><a name="uri">Connections to the VMware ESX driver</a></h2>
<p>
Some example remote connection URIs for the driver are:
</p>
<pre>
vpx://example-vcenter.com/dc1/srv1 (VPX over HTTPS, select ESX server 'srv1' in datacenter 'dc1')
esx://example-esx.com (ESX over HTTPS)
gsx://example-gsx.com (GSX over HTTPS)
esx://example-esx.com/?transport=http (ESX over HTTP)
esx://example-esx.com/?no_verify=1 (ESX over HTTPS, but doesn't verify the server's SSL certificate)
</pre>
<p>
<strong>Note</strong>: In contrast to other drivers, the ESX driver is
a client-side-only driver. It connects to the ESX server using HTTP(S).
Therefore, the <a href="remote.html">remote transport mechanism</a>
provided by the remote driver and libvirtd will not work, and you
cannot use URIs like <code>esx+ssh://example.com</code>.
</p>
<h3><a name="uriformat">URI Format</a></h3>
<p>
URIs have this general form (<code>[...]</code> marks an optional part).
</p>
<pre>
type://[username@]hostname[:port]/[[folder/...]datacenter/[folder/...][cluster/]server][?extraparameters]
</pre>
<p>
The <code>type://</code> is either <code>esx://</code> or
<code>gsx://</code> or <code>vpx://</code> <span class="since">since 0.8.3</span>.
The driver selects the default port depending on the <code>type://</code>.
For <code>esx://</code> and <code>vpx://</code> the default HTTPS port
is 443, for <code>gsx://</code> it is 8333.
If the port parameter is given, it overrides the default port.
</p>
<p>
A <code>vpx://</code> connection is currently restricted to a single
ESX server. This might be relaxed in the future. The path part of the
URI is used to specify the datacenter and the ESX server in it. If the
ESX server is part of a cluster then the cluster has to be specified too.
</p>
<p>
An example: ESX server <code>example-esx.com</code> is managed by
vCenter <code>example-vcenter.com</code> and part of cluster
<code>cluster1</code>. This cluster is part of datacenter <code>dc1</code>.
</p>
<pre>
vpx://example-vcenter.com/dc1/cluster1/example-esx.com
</pre>
<p>
Datacenters and clusters can be organized in folders, those have to be
specified as well. The driver can handle folders
<span class="since">since 0.9.7</span>.
</p>
<pre>
vpx://example-vcenter.com/folder1/dc1/folder2/example-esx.com
</pre>
<h4><a name="extraparams">Extra parameters</a></h4>
<p>
Extra parameters can be added to a URI as part of the query string
(the part following <code>?</code>). A single parameter is formed by a
<code>name=value</code> pair. Multiple parameters are separated by
<code>&</code>.
</p>
<pre>
?<span style="color: #E50000">no_verify=1</span>&<span style="color: #00B200">auto_answer=1</span>&<span style="color: #0000E5">proxy=socks://example-proxy.com:23456</span>
</pre>
<p>
The driver understands the extra parameters shown below.
</p>
<table class="top_table">
<tr>
<th>Name</th>
<th>Values</th>
<th>Meaning</th>
</tr>
<tr>
<td>
<code>transport</code>
</td>
<td>
<code>http</code> or <code>https</code>
</td>
<td>
Overrides the default HTTPS transport. For <code>esx://</code>
and <code>vpx://</code> the default HTTP port is 80, for
<code>gsx://</code> it is 8222.
</td>
</tr>
<tr>
<td>
<code>vcenter</code>
</td>
<td>
Hostname of a VMware vCenter or <code>*</code>
</td>
<td>
In order to perform a migration the driver needs to know the
VMware vCenter for the ESX server. If set to <code>*</code>,
the driver connects to the vCenter known to the ESX server.
This parameter in useful when connecting to an ESX server only.
</td>
</tr>
<tr>
<td>
<code>no_verify</code>
</td>
<td>
<code>0</code> or <code>1</code>
</td>
<td>
If set to 1, this disables libcurl client checks of the server's
SSL certificate. The default value it 0. See the
<a href="#certificates">Certificates for HTTPS</a> section for
details.
</td>
</tr>
<tr>
<td>
<code>auto_answer</code>
</td>
<td>
<code>0</code> or <code>1</code>
</td>
<td>
If set to 1, the driver answers all
<a href="#questions">questions</a> with the default answer.
If set to 0, questions are reported as errors. The default
value it 0. <span class="since">Since 0.7.5</span>.
</td>
</tr>
<tr>
<td>
<code>proxy</code>
</td>
<td>
<code>[type://]hostname[:port]</code>
</td>
<td>
Allows to specify a proxy for HTTP and HTTPS communication.
<span class="since">Since 0.8.2</span>.
The optional <code>type</code> part may be one of:
<code>http</code>, <code>socks</code>, <code>socks4</code>,
<code>socks4a</code> or <code>socks5</code>. The default is
<code>http</code> and <code>socks</code> is synonymous for
<code>socks5</code>. The optional <code>port</code> allows to
override the default port 1080.
</td>
</tr>
</table>
<h3><a name="auth">Authentication</a></h3>
<p>
In order to perform any useful operation the driver needs to log into
the ESX server. Therefore, only <code>virConnectOpenAuth</code> can be
used to connect to an ESX server, <code>virConnectOpen</code> and
<code>virConnectOpenReadOnly</code> don't work.
To log into an ESX server or vCenter the driver will request
credentials using the callback passed to the
<code>virConnectOpenAuth</code> function. The driver passes the
hostname as challenge parameter to the callback. This enables the
callback to distinguish between requests for ESX server and vCenter.
</p>
<p>
<strong>Note</strong>: During the ongoing driver development, testing
is done using an unrestricted <code>root</code> account. Problems may
occur if you use a restricted account. Detailed testing with restricted
accounts has not been done yet.
</p>
<h3><a name="certificates">Certificates for HTTPS</a></h3>
<p>
By default the ESX driver uses HTTPS to communicate with an ESX server.
Proper HTTPS communication requires correctly configured SSL
certificates. This certificates are different from the ones libvirt
uses for <a href="remote.html">secure communication over TLS</a> to a
libvirtd one a remote server.
</p>
<p>
By default the driver tries to verify the server's SSL certificate
using the CA certificate pool installed on your client computer. With
an out-of-the-box installed ESX server this won't work, because a newly
installed ESX server uses auto-generated self-signed certificates.
Those are singed by a CA certificate that is typically not known to your
client computer and libvirt will report an error like this one:
</p>
<pre>
error: internal error curl_easy_perform() returned an error: Peer certificate cannot be authenticated with known CA certificates (60)
</pre>
<p>
Where are two ways to solve this problem:
</p>
<ul>
<li>
Use the <code>no_verify=1</code> <a href="#extraparams">extra parameter</a>
to disable server certificate verification.
</li>
<li>
Generate new SSL certificates signed by a CA known to your client
computer and replace the original ones on your ESX server. See the
section <i>Replace a Default Certificate with a CA-Signed Certificate</i>
in the <a href="http://www.vmware.com/pdf/vsphere4/r40/vsp_40_esx_server_config.pdf">ESX Configuration Guide</a>
</li>
</ul>
<h3><a name="connproblems">Connection problems</a></h3>
<p>
There are also other causes for connection problems than the
<a href="#certificates">HTTPS certificate</a> related ones.
</p>
<ul>
<li>
As stated before the ESX driver doesn't need the
<a href="remote.html">remote transport mechanism</a>
provided by the remote driver and libvirtd, nor does the ESX driver
support it. Therefore, using an URI including a transport in the
scheme won't work. Only <a href="#uriformat">URIs as described</a>
are supported by the ESX driver. Here's a collection of possible
error messages:
<pre>
$ virsh -c esx+tcp://example.com/
error: unable to connect to libvirtd at 'example.com': Connection refused
</pre>
<pre>
$ virsh -c esx+tls://example.com/
error: Cannot access CA certificate '/etc/pki/CA/cacert.pem': No such file or directory
</pre>
<pre>
$ virsh -c esx+ssh://example.com/
error: cannot recv data: ssh: connect to host example.com port 22: Connection refused
</pre>
<pre>
$ virsh -c esx+ssh://example.com/
error: cannot recv data: Resource temporarily unavailable
</pre>
</li>
<li>
<span class="since">Since 0.7.0</span> libvirt contains the ESX
driver. Earlier versions of libvirt will report a misleading error
about missing certificates when you try to connect to an ESX server.
<pre>
$ virsh -c esx://example.com/
error: Cannot access CA certificate '/etc/pki/CA/cacert.pem': No such file or directory
</pre>
<p>
Don't let this error message confuse you. Setting up certificates
as described on the <a href="remote.html#Remote_certificates">remote transport mechanism</a> page
does not help, as this is not a certificate related problem.
</p>
<p>
To fix this problem you need to update your libvirt to 0.7.0 or newer.
You may also see this error when you use a libvirt version that
contains the ESX driver but you or your distro disabled the ESX
driver during compilation. <span class="since">Since 0.8.3</span>
the error message has been improved in this case:
</p>
<pre>
$ virsh -c esx://example.com/
error: invalid argument in libvirt was built without the 'esx' driver
</pre>
</li>
</ul>
<h2><a name="questions">Questions blocking tasks</a></h2>
<p>
Some methods of the VI API start tasks, for example
<code>PowerOnVM_Task()</code>. Such tasks may be blocked by questions
if the ESX server detects an issue with the domain that requires user
interaction. The ESX driver cannot prompt the user to answer a
question, libvirt doesn't have an API for something like this.
</p>
<p>
The VI API provides the <code>AnswerVM()</code> method to
programmatically answer a questions. So the driver has two options
how to handle such a situation: either answer the questions with the
default answer or report the question as an error and cancel the
blocked task if possible. The
<a href="#uriformat"><code>auto_answer</code></a> query parameter
controls the answering behavior.
</p>
<h2><a name="xmlspecial">Specialties in the domain XML config</a></h2>
<p>
There are several specialties in the domain XML config for ESX domains.
</p>
<h3><a name="restrictions">Restrictions</a></h3>
<p>
There are some restrictions for some values of the domain XML config.
The driver will complain if this restrictions are violated.
</p>
<ul>
<li>
Memory size has to be a multiple of 4096
</li>
<li>
Number of virtual CPU has to be 1 or a multiple of 2
</li>
<li>
Valid MAC address prefixes are <code>00:0c:29</code> and
<code>00:50:56</code>. <span class="since">Since 0.7.6</span>
arbitrary <a href="#macaddresses">MAC addresses</a> are supported.
</li>
</ul>
<h3><a name="datastore">Datastore references</a></h3>
<p>
Storage is managed in datastores. VMware uses a special path format to
reference files in a datastore. Basically, the datastore name is put
into squared braces in front of the path.
</p>
<pre>
[datastore] directory/filename
</pre>
<p>
To define a new domain the driver converts the domain XML into a
VMware VMX file and uploads it to a datastore known to the ESX server.
Because multiple datastores may be known to an ESX server the driver
needs to decide to which datastore the VMX file should be uploaded.
The driver deduces this information from the path of the source of the
first file-based harddisk listed in the domain XML.
</p>
<h3><a name="macaddresses">MAC addresses</a></h3>
<p>
VMware has registered two MAC address prefixes for domains:
<code>00:0c:29</code> and <code>00:50:56</code>. These prefixes are
split into ranges for different purposes.
</p>
<table class="top_table">
<tr>
<th>Range</th>
<th>Purpose</th>
</tr>
<tr>
<td>
<code>00:0c:29:00:00:00</code> - <code>00:0c:29:ff:ff:ff</code>
</td>
<td>
An ESX server autogenerates MAC addresses from this range if
the VMX file doesn't contain a MAC address when trying to start
a domain.
</td>
</tr>
<tr>
<td>
<code>00:50:56:00:00:00</code> - <code>00:50:56:3f:ff:ff</code>
</td>
<td>
MAC addresses from this range can by manually assigned by the
user in the VI client.
</td>
</tr>
<tr>
<td>
<code>00:50:56:80:00:00</code> - <code>00:50:56:bf:ff:ff</code>
</td>
<td>
A VI client autogenerates MAC addresses from this range for
newly defined domains.
</td>
</tr>
</table>
<p>
The VMX files generated by the ESX driver always contain a MAC address,
because libvirt generates a random one if an interface element in the
domain XML file lacks a MAC address.
<span class="since">Since 0.7.6</span> the ESX driver sets the prefix
for generated MAC addresses to <code>00:0c:29</code>. Before 0.7.6
the <code>00:50:56</code> prefix was used. Sometimes this resulted in
the generation of out-of-range MAC address that were rejected by the
ESX server.
</p>
<p>
Also <span class="since">since 0.7.6</span> every MAC address outside
this ranges can be used. For such MAC addresses the ESX server-side
check is disabled in the VMX file to stop the ESX server from rejecting
out-of-predefined-range MAC addresses.
</p>
<pre>
ethernet0.checkMACAddress = "false"
</pre>
<h3><a name="hardware">Available hardware</a></h3>
<p>
VMware ESX supports different models of SCSI controllers and network
cards.
</p>
<h4>SCSI controller models</h4>
<dl>
<dt><code>auto</code></dt>
<dd>
This isn't a actual controller model. If specified the ESX driver
tries to detect the SCSI controller model referenced in the
<code>.vmdk</code> file and use it. Autodetection fails when a
SCSI controller has multiple disks attached and the SCSI controller
models referenced in the <code>.vmdk</code> files are inconsistent.
<span class="since">Since 0.8.3</span>
</dd>
<dt><code>buslogic</code></dt>
<dd>
BusLogic SCSI controller for older guests.
</dd>
<dt><code>lsilogic</code></dt>
<dd>
LSI Logic SCSI controller for recent guests.
</dd>
<dt><code>lsisas1068</code></dt>
<dd>
LSI Logic SAS 1068 controller. <span class="since">Since 0.8.0</span>
</dd>
<dt><code>vmpvscsi</code></dt>
<dd>
Special VMware Paravirtual SCSI controller, requires VMware tools inside
the guest. See <a href="http://kb.vmware.com/kb/1010398">VMware KB1010398</a>
for details. <span class="since">Since 0.8.3</span>
</dd>
</dl>
<p>
Here a domain XML snippet:
</p>
<pre>
...
<disk type='file' device='disk'>
<source file='[local-storage] Fedora11/Fedora11.vmdk'/>
<target dev='sda' bus='scsi'/>
<address type='drive' controller='0' bus='0' unit='0'/>
</disk>
<controller type='scsi' index='0' model='<strong>lsilogic</strong>'/>
...
</pre>
<p>
The controller element is supported <span class="since">since 0.8.2</span>.
Prior to this <code><driver name='lsilogic'/></code> was abused to
specify the SCSI controller model. This attribute usage is deprecated now.
</p>
<pre>
...
<disk type='file' device='disk'>
<driver name='<strong>lsilogic</strong>'/>
<source file='[local-storage] Fedora11/Fedora11.vmdk'/>
<target dev='sda' bus='scsi'/>
</disk>
...
</pre>
<h4>Network card models</h4>
<dl>
<dt><code>vlance</code></dt>
<dd>
AMD PCnet32 network card for older guests.
</dd>
<dt><code>vmxnet</code>, <code>vmxnet2</code>, <code>vmxnet3</code></dt>
<dd>
Special VMware VMXnet network card, requires VMware tools inside
the guest. See <a href="http://kb.vmware.com/kb/1001805">VMware KB1001805</a>
for details.
</dd>
<dt><code>e1000</code></dt>
<dd>
Intel E1000 network card for recent guests.
</dd>
</dl>
<p>
Here a domain XML snippet:
</p>
<pre>
...
<interface type='bridge'>
<mac address='00:50:56:25:48:c7'/>
<source bridge='VM Network'/>
<model type='<strong>e1000</strong>'/>
</interface>
...
</pre>
<h2><a name="importexport">Import and export of domain XML configs</a></h2>
<p>
The ESX driver currently supports a native config format known as
<code>vmware-vmx</code> to handle VMware VMX configs.
</p>
<h3><a name="xmlimport">Converting from VMware VMX config to domain XML config</a></h3>
<p>
The <code>virsh domxml-from-native</code> provides a way to convert an
existing VMware VMX config into a domain XML config that can then be
used by libvirt.
</p>
<pre>
$ cat > demo.vmx << EOF
#!/usr/bin/vmware
config.version = "8"
virtualHW.version = "4"
floppy0.present = "false"
nvram = "Fedora11.nvram"
deploymentPlatform = "windows"
virtualHW.productCompatibility = "hosted"
tools.upgrade.policy = "useGlobal"
powerType.powerOff = "default"
powerType.powerOn = "default"
powerType.suspend = "default"
powerType.reset = "default"
displayName = "Fedora11"
extendedConfigFile = "Fedora11.vmxf"
scsi0.present = "true"
scsi0.sharedBus = "none"
scsi0.virtualDev = "lsilogic"
memsize = "1024"
scsi0:0.present = "true"
scsi0:0.fileName = "/vmfs/volumes/498076b2-02796c1a-ef5b-000ae484a6a3/Fedora11/Fedora11.vmdk"
scsi0:0.deviceType = "scsi-hardDisk"
ide0:0.present = "true"
ide0:0.clientDevice = "true"
ide0:0.deviceType = "cdrom-raw"
ide0:0.startConnected = "false"
ethernet0.present = "true"
ethernet0.networkName = "VM Network"
ethernet0.addressType = "vpx"
ethernet0.generatedAddress = "00:50:56:91:48:c7"
chipset.onlineStandby = "false"
guestOSAltName = "Red Hat Enterprise Linux 5 (32-Bit)"
guestOS = "rhel5"
uuid.bios = "50 11 5e 16 9b dc 49 d7-f1 71 53 c4 d7 f9 17 10"
snapshot.action = "keep"
sched.cpu.min = "0"
sched.cpu.units = "mhz"
sched.cpu.shares = "normal"
sched.mem.minsize = "0"
sched.mem.shares = "normal"
toolScripts.afterPowerOn = "true"
toolScripts.afterResume = "true"
toolScripts.beforeSuspend = "true"
toolScripts.beforePowerOff = "true"
scsi0:0.redo = ""
tools.syncTime = "false"
uuid.location = "56 4d b5 06 a2 bd fb eb-ae 86 f7 d8 49 27 d0 c4"
sched.cpu.max = "unlimited"
sched.swap.derivedName = "/vmfs/volumes/498076b2-02796c1a-ef5b-000ae484a6a3/Fedora11/Fedora11-7de040d8.vswp"
tools.remindInstall = "TRUE"
EOF
$ virsh -c esx://example.com domxml-from-native vmware-vmx demo.vmx
Enter username for example.com [root]:
Enter root password for example.com:
<domain type='vmware'>
<name>Fedora11</name>
<uuid>50115e16-9bdc-49d7-f171-53c4d7f91710</uuid>
<memory>1048576</memory>
<currentMemory>1048576</currentMemory>
<vcpu>1</vcpu>
<os>
<type arch='i686'>hvm</type>
</os>
<clock offset='utc'/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<devices>
<disk type='file' device='disk'>
<source file='[local-storage] Fedora11/Fedora11.vmdk'/>
<target dev='sda' bus='scsi'/>
<address type='drive' controller='0' bus='0' unit='0'/>
</disk>
<controller type='scsi' index='0' model='lsilogic'/>
<interface type='bridge'>
<mac address='00:50:56:91:48:c7'/>
<source bridge='VM Network'/>
</interface>
</devices>
</domain>
</pre>
<h3><a name="xmlexport">Converting from domain XML config to VMware VMX config</a></h3>
<p>
The <code>virsh domxml-to-native</code> provides a way to convert a
domain XML config into a VMware VMX config.
</p>
<pre>
$ cat > demo.xml << EOF
<domain type='vmware'>
<name>Fedora11</name>
<uuid>50115e16-9bdc-49d7-f171-53c4d7f91710</uuid>
<memory>1048576</memory>
<currentMemory>1048576</currentMemory>
<vcpu>1</vcpu>
<os>
<type arch='x86_64'>hvm</type>
</os>
<devices>
<disk type='file' device='disk'>
<source file='[local-storage] Fedora11/Fedora11.vmdk'/>
<target dev='sda' bus='scsi'/>
<address type='drive' controller='0' bus='0' unit='0'/>
</disk>
<controller type='scsi' index='0' model='lsilogic'/>
<interface type='bridge'>
<mac address='00:50:56:25:48:c7'/>
<source bridge='VM Network'/>
</interface>
</devices>
</domain>
EOF
$ virsh -c esx://example.com domxml-to-native vmware-vmx demo.xml
Enter username for example.com [root]:
Enter root password for example.com:
config.version = "8"
virtualHW.version = "4"
guestOS = "other-64"
uuid.bios = "50 11 5e 16 9b dc 49 d7-f1 71 53 c4 d7 f9 17 10"
displayName = "Fedora11"
memsize = "1024"
numvcpus = "1"
scsi0.present = "true"
scsi0.virtualDev = "lsilogic"
scsi0:0.present = "true"
scsi0:0.deviceType = "scsi-hardDisk"
scsi0:0.fileName = "/vmfs/volumes/local-storage/Fedora11/Fedora11.vmdk"
ethernet0.present = "true"
ethernet0.networkName = "VM Network"
ethernet0.connectionType = "bridged"
ethernet0.addressType = "static"
ethernet0.address = "00:50:56:25:48:C7"
</pre>
<h2><a name="xmlconfig">Example domain XML configs</a></h2>
<h3>Fedora11 on x86_64</h3>
<pre>
<domain type='vmware'>
<name>Fedora11</name>
<uuid>50115e16-9bdc-49d7-f171-53c4d7f91710</uuid>
<memory>1048576</memory>
<currentMemory>1048576</currentMemory>
<vcpu>1</vcpu>
<os>
<type arch='x86_64'>hvm</type>
</os>
<devices>
<disk type='file' device='disk'>
<source file='[local-storage] Fedora11/Fedora11.vmdk'/>
<target dev='sda' bus='scsi'/>
<address type='drive' controller='0' bus='0' unit='0'/>
</disk>
<controller type='scsi' index='0'/>
<interface type='bridge'>
<mac address='00:50:56:25:48:c7'/>
<source bridge='VM Network'/>
</interface>
</devices>
</domain>
</pre>
<h2><a name="migration">Migration</a></h2>
<p>
A migration cannot be initiated on an ESX server directly, a VMware
vCenter is necessary for this. The <code>vcenter</code> query
parameter must be set either to the hostname or IP address of the
vCenter managing the ESX server or to <code>*</code>. Setting it
to <code>*</code> causes the driver to connect to the vCenter known to
the ESX server. If the ESX server is not managed by a vCenter an error
is reported.
</p>
<pre>
esx://example.com/?vcenter=example-vcenter.com
</pre>
<p>
Here's an example how to migrate the domain <code>Fedora11</code> from
ESX server <code>example-src.com</code> to ESX server
<code>example-dst.com</code> implicitly involving vCenter
<code>example-vcenter.com</code> using <code>virsh</code>.
</p>
<pre>
$ virsh -c esx://example-src.com/?vcenter=* migrate Fedora11 esx://example-dst.com/?vcenter=*
Enter username for example-src.com [root]:
Enter root password for example-src.com:
Enter username for example-vcenter.com [administrator]:
Enter administrator password for example-vcenter.com:
Enter username for example-dst.com [root]:
Enter root password for example-dst.com:
Enter username for example-vcenter.com [administrator]:
Enter administrator password for example-vcenter.com:
</pre>
<p>
<span class="since">Since 0.8.3</span> you can directly connect to a vCenter.
This simplifies migration a bit. Here's the same migration as above but
using <code>vpx://</code> connections and assuming both ESX server are in
datacenter <code>dc1</code> and aren't part of a cluster.
</p>
<pre>
$ virsh -c vpx://example-vcenter.com/dc1/example-src.com migrate Fedora11 vpx://example-vcenter.com/dc1/example-dst.com
Enter username for example-vcenter.com [administrator]:
Enter administrator password for example-vcenter.com:
Enter username for example-vcenter.com [administrator]:
Enter administrator password for example-vcenter.com:
</pre>
<h2><a name="scheduler">Scheduler configuration</a></h2>
<p>
The driver exposes the ESX CPU scheduler. The parameters listed below
are available to control the scheduler.
</p>
<dl>
<dt><code>reservation</code></dt>
<dd>
The amount of CPU resource in MHz that is guaranteed to be
available to the domain. Valid values are 0 and greater.
</dd>
<dt><code>limit</code></dt>
<dd>
The CPU utilization of the domain will be
limited to this value in MHz, even if more CPU resources are
available. If the limit is set to -1, the CPU utilization of the
domain is unlimited. If the limit is not set to -1, it must be
greater than or equal to the reservation.
</dd>
<dt><code>shares</code></dt>
<dd>
Shares are used to determine relative CPU
allocation between domains. In general, a domain with more shares
gets proportionally more of the CPU resource. Valid values are 0
and greater. The special values -1, -2 and -3 represent the
predefined shares level <code>low</code>, <code>normal</code> and
<code>high</code>.
</dd>
</dl>
<h2><a name="tools">VMware tools</a></h2>
<p>
Some actions require installed VMware tools. If the VMware tools are
not installed in the guest and one of the actions below is to be
performed the ESX server raises an error and the driver reports it.
</p>
<ul>
<li>
<code>virDomainReboot</code>
</li>
<li>
<code>virDomainShutdown</code>
</li>
</ul>
<h2><a name="links">Links</a></h2>
<ul>
<li>
<a href="http://www.vmware.com/support/developer/vc-sdk/">
VMware vSphere Web Services SDK Documentation
</a>
</li>
<li>
<a href="http://www.vmware.com/pdf/esx3_memory.pdf">
The Role of Memory in VMware ESX Server 3
</a>
</li>
<li>
<a href="http://www.sanbarrow.com/vmx.html">
VMware VMX config parameters
</a>
</li>
<li>
<a href="http://www.vmware.com/pdf/vsp_4_pvscsi_perf.pdf">
VMware ESX 4.0 PVSCSI Storage Performance
</a>
</li>
</ul>
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