org.libvirt

Class Domain

public class Domain extends Object

A virtual machine defined within libvirt.

Field Summary
protected Libvirt	libvirt The libvirt connection from the hypervisor

Method Summary
void	attachDevice(String xmlDesc) Creates a virtual device attachment to backend.
DomainBlockStats	blockStats(String path) Returns block device (disk) stats for block devices attached to this domain.
void	coreDump(String to, int flags) Dumps the core of this domain on a given file for analysis.
int	cpuMapLength(int maxCpus) It returns the length (in bytes) required to store the complete CPU map between a single virtual & all physical CPUs of a domain.
void	create() Launches this defined domain.
void	destroy() Destroys this domain object.
void	detachDevice(String xmlDesc) Destroys a virtual device attachment to backend.
int	free() Frees this domain object.
boolean	getAutostart() Provides a boolean value indicating whether the network is configured to be automatically started when the host machine boots.
Connect	getConnect() Provides the connection object associated with a domain.
int	getID() Gets the hypervisor ID number for the domain
DomainInfo	getInfo() Extract information about a domain.
long	getMaxMemory() Retrieve the maximum amount of physical memory allocated to a domain.
int	getMaxVcpus() Provides the maximum number of virtual CPUs supported for the guest VM.
String	getName() Gets the public name for this domain
String	getOSType() Gets the type of domain operation system.
SchedParameter[]	getSchedulerParameters() Gets the scheduler parameters.
String[]	getSchedulerType() Gets the scheduler type.
int[]	getUUID() Get the UUID for this domain.
String	getUUIDString() Gets the UUID for this domain as string.
int[]	getVcpusCpuMaps() Returns the cpumaps for this domain Only the lower 8 bits of each int in the array contain information.
VcpuInfo[]	getVcpusInfo() Extracts information about virtual CPUs of this domain
String	getXMLDesc(int flags) Provides an XML description of the domain.
DomainInterfaceStats	interfaceStats(String path) Returns network interface stats for interfaces attached to this domain.
Domain	migrate(Connect dconn, long flags, String dname, String uri, long bandwidth) Migrate this domain object from its current host to the destination host given by dconn (a connection to the destination host).
void	pinVcpu(int vcpu, int[] cpumap) Dynamically changes the real CPUs which can be allocated to a virtual CPU.
protected void	processError() Error handling logic to throw errors.
void	reboot(int flags) Reboot this domain, the domain object is still usable there after but the domain OS is being stopped for a restart.
void	resume() Resume this suspended domain, the process is restarted from the state where it was frozen by calling virSuspendDomain().
void	save(String to) Suspends this domain and saves its memory contents to a file on disk.
void	setAutostart(boolean autostart) Configures the network to be automatically started when the host machine boots.
void	setMaxMemory(long memory) * Dynamically change the maximum amount of physical memory allocated to a domain.
void	setMemory(long memory) Dynamically changes the target amount of physical memory allocated to this domain.
void	setSchedulerParameters(SchedParameter[] params) Changes the scheduler parameters
void	setVcpus(int nvcpus) Dynamically changes the number of virtual CPUs used by this domain.
void	shutdown() Shuts down this domain, the domain object is still usable there after but the domain OS is being stopped.
void	suspend() Suspends this active domain, the process is frozen without further access to CPU resources and I/O but the memory used by the domain at the hypervisor level will stay allocated.
void	undefine() undefines this domain but does not stop it if it is running

Field Detail

libvirt

protected Libvirt libvirt

The libvirt connection from the hypervisor

Method Detail

attachDevice

public void attachDevice(String xmlDesc)

Creates a virtual device attachment to backend.

Parameters: xmlDesc XML description of one device

Throws: LibvirtException

blockStats

public DomainBlockStats blockStats(String path)

Returns block device (disk) stats for block devices attached to this domain. The path parameter is the name of the block device. Get this by calling virDomainGetXMLDesc and finding the attribute within //domain/devices/disk. (For example, "xvda"). Domains may have more than one block device. To get stats for each you should make multiple calls to this function. Individual fields within the DomainBlockStats object may be returned as -1, which indicates that the hypervisor does not support that particular statistic.

Parameters: path path to the block device

Returns: the statistics in a DomainBlockStats object

Throws: LibvirtException

coreDump

public void coreDump(String to, int flags)

Dumps the core of this domain on a given file for analysis. Note that for remote Xen Daemon the file path will be interpreted in the remote host.

Parameters: to path for the core file flags extra flags, currently unused

Throws: LibvirtException

cpuMapLength

public int cpuMapLength(int maxCpus)

It returns the length (in bytes) required to store the complete CPU map between a single virtual & all physical CPUs of a domain.

create

public void create()

Launches this defined domain. If the call succeed the domain moves from the defined to the running domains pools.

Throws: LibvirtException

destroy

public void destroy()

Destroys this domain object. The running instance is shutdown if not down already and all resources used by it are given back to the hypervisor. The data structure is freed and should not be used thereafter if the call does not return an error. This function may requires priviledged access

Throws: LibvirtException

detachDevice

public void detachDevice(String xmlDesc)

Destroys a virtual device attachment to backend.

Parameters: xmlDesc XML description of one device

Throws: LibvirtException

free

public int free()

Frees this domain object. The running instance is kept alive. The data structure is freed and should not be used thereafter.

Throws: LibvirtException

UNKNOWN: 0 for success, -1 for failure.

getAutostart

public boolean getAutostart()

Provides a boolean value indicating whether the network is configured to be automatically started when the host machine boots.

Returns: the result

Throws: LibvirtException

getConnect

public Connect getConnect()

Provides the connection object associated with a domain.

Returns: the Connect object

getID

public int getID()

Gets the hypervisor ID number for the domain

Returns: the hypervisor ID

Throws: LibvirtException

getInfo

public DomainInfo getInfo()

Extract information about a domain. Note that if the connection used to get the domain is limited only a partial set of the information can be extracted.

Returns: a DomainInfo object describing this domain

Throws: LibvirtException

getMaxMemory

public long getMaxMemory()

Retrieve the maximum amount of physical memory allocated to a domain.

Returns: the memory in kilobytes

Throws: LibvirtException

getMaxVcpus

public int getMaxVcpus()

Provides the maximum number of virtual CPUs supported for the guest VM. If the guest is inactive, this is basically the same as virConnectGetMaxVcpus. If the guest is running this will reflect the maximum number of virtual CPUs the guest was booted with.

Returns: the number of VCPUs

Throws: LibvirtException

getName

public String getName()

Gets the public name for this domain

Returns: the name

Throws: LibvirtException

getOSType

public String getOSType()

Gets the type of domain operation system.

Returns: the type

Throws: LibvirtException

getSchedulerParameters

public SchedParameter[] getSchedulerParameters()

Gets the scheduler parameters.

Returns: an array of SchedParameter objects

Throws: LibvirtException

getSchedulerType

public String[] getSchedulerType()

Gets the scheduler type.

Returns: the type of the scheduler

Throws: LibvirtException

getUUID

public int[] getUUID()

Get the UUID for this domain.

Returns: the UUID as an unpacked int array

Throws: LibvirtException

getUUIDString

public String getUUIDString()

Gets the UUID for this domain as string.

Returns: the UUID in canonical String format

Throws: LibvirtException

getVcpusCpuMaps

public int[] getVcpusCpuMaps()

Returns the cpumaps for this domain Only the lower 8 bits of each int in the array contain information.

Returns: a bitmap of real CPUs for all vcpus of this domain

Throws: LibvirtException

getVcpusInfo

public VcpuInfo[] getVcpusInfo()

Extracts information about virtual CPUs of this domain

Returns: an array of VcpuInfo object describing the VCPUs

Throws: LibvirtException

getXMLDesc

public String getXMLDesc(int flags)

Provides an XML description of the domain. The description may be reused later to relaunch the domain with createLinux().

Parameters: flags not used

Returns: the XML description String

Throws: LibvirtException

interfaceStats

public DomainInterfaceStats interfaceStats(String path)

Returns network interface stats for interfaces attached to this domain. The path parameter is the name of the network interface. Domains may have more than network interface. To get stats for each you should make multiple calls to this function. Individual fields within the DomainInterfaceStats object may be returned as -1, which indicates that the hypervisor does not support that particular statistic.

Parameters: path path to the interface

Returns: the statistics in a DomainInterfaceStats object

Throws: LibvirtException

migrate

public Domain migrate(Connect dconn, long flags, String dname, String uri, long bandwidth)

Migrate this domain object from its current host to the destination host given by dconn (a connection to the destination host). Flags may be one of more of the following: Domain.VIR_MIGRATE_LIVE Attempt a live migration. If a hypervisor supports renaming domains during migration, then you may set the dname parameter to the new name (otherwise it keeps the same name). If this is not supported by the hypervisor, dname must be NULL or else you will get an error. Since typically the two hypervisors connect directly to each other in order to perform the migration, you may need to specify a path from the source to the destination. This is the purpose of the uri parameter.If uri is NULL, then libvirt will try to find the best method. Uri may specify the hostname or IP address of the destination host as seen from the source, or uri may be a URI giving transport, hostname, user, port, etc. in the usual form. Uri should only be specified if you want to migrate over a specific interface on the remote host. For Qemu/KVM, the uri should be of the form "tcp://hostname[:port]". This does not require TCP auth to be setup between the connections, since migrate uses a straight TCP connection (unless using the PEER2PEER flag, in which case URI should be a full fledged libvirt URI). Refer also to driver documentation for the particular URIs supported. If set to 0, libvirt will choose a suitable default. Some hypervisors do not support this feature and will return an error if bandwidth is not 0. To see which features are supported by the current hypervisor, see Connect.getCapabilities, /capabilities/host/migration_features. There are many limitations on migration imposed by the underlying technology - for example it may not be possible to migrate between different processors even with the same architecture, or between different types of hypervisor.

Parameters: dconn destination host (a Connect object) flags flags dname (optional) rename domain to this at destination uri (optional) dest hostname/URI as seen from the source host bandwidth optional) specify migration bandwidth limit in Mbps

Returns: the new domain object if the migration was successful, or NULL in case of error. Note that the new domain object exists in the scope of the destination connection (dconn).

Throws: LibvirtException

pinVcpu

public void pinVcpu(int vcpu, int[] cpumap)

Dynamically changes the real CPUs which can be allocated to a virtual CPU. This function requires priviledged access to the hypervisor.

Parameters: vcpu virtual cpu number cpumap bit map of real CPUs represented by the the lower 8 bits of each int in the array. Each bit set to 1 means that corresponding CPU is usable. Bytes are stored in little-endian order: CPU0-7, 8-15... In each byte, lowest CPU number is least significant bit.

Throws: LibvirtException

processError

protected void processError()

Error handling logic to throw errors. Must be called after every libvirt call.

reboot

public void reboot(int flags)

Reboot this domain, the domain object is still usable there after but the domain OS is being stopped for a restart. Note that the guest OS may ignore the request.

Parameters: flags extra flags for the reboot operation, not used yet

Throws: LibvirtException

resume

public void resume()

Resume this suspended domain, the process is restarted from the state where it was frozen by calling virSuspendDomain(). This function may requires privileged access

Throws: LibvirtException

save

public void save(String to)

Suspends this domain and saves its memory contents to a file on disk. After the call, if successful, the domain is not listed as running anymore (this may be a problem). Use Connect.virDomainRestore() to restore a domain after saving.

Parameters: to path for the output file

Throws: LibvirtException

setAutostart

public void setAutostart(boolean autostart)

Configures the network to be automatically started when the host machine boots.

Parameters: autostart

Throws: LibvirtException

setMaxMemory

public void setMaxMemory(long memory)

* Dynamically change the maximum amount of physical memory allocated to a domain. This function requires priviledged access to the hypervisor.

Parameters: memory the amount memory in kilobytes

Throws: LibvirtException

setMemory

public void setMemory(long memory)

Dynamically changes the target amount of physical memory allocated to this domain. This function may requires priviledged access to the hypervisor.

Parameters: memory in kilobytes

Throws: LibvirtException

setSchedulerParameters

public void setSchedulerParameters(SchedParameter[] params)

Changes the scheduler parameters

Parameters: params an array of SchedParameter objects to be changed

Throws: LibvirtException

setVcpus

public void setVcpus(int nvcpus)

Dynamically changes the number of virtual CPUs used by this domain. Note that this call may fail if the underlying virtualization hypervisor does not support it or if growing the number is arbitrary limited. This function requires priviledged access to the hypervisor.

Parameters: nvcpus the new number of virtual CPUs for this domain

Throws: LibvirtException

shutdown

public void shutdown()

Shuts down this domain, the domain object is still usable there after but the domain OS is being stopped. Note that the guest OS may ignore the request. TODO: should we add an option for reboot, knowing it may not be doable in the general case ?

Throws: LibvirtException

suspend

public void suspend()

Suspends this active domain, the process is frozen without further access to CPU resources and I/O but the memory used by the domain at the hypervisor level will stay allocated. Use Domain.resume() to reactivate the domain. This function requires priviledged access.

Throws: LibvirtException

undefine

public void undefine()

undefines this domain but does not stop it if it is running

Throws: LibvirtException