Package org.cloudbus.cloudsim.allocationpolicies

Class VmAllocationPolicyFirstFit

java.lang.Object

org.cloudbus.cloudsim.allocationpolicies.VmAllocationPolicyAbstract

org.cloudbus.cloudsim.allocationpolicies.VmAllocationPolicyFirstFit

All Implemented Interfaces:

VmAllocationPolicy

public class VmAllocationPolicyFirstFit
extends VmAllocationPolicyAbstract
implements VmAllocationPolicy

A First Fit VM allocation policy which finds the first Host having suitable resources to place a given VM. This is a high time-efficient policy with a best-case complexity O(1) and a worst-case complexity O(N), where N is the number of Hosts. Additionally, such a policy is resource efficient, because it performs server consolidation by trying to place the maximum number of VMs into the same Host in order to increase Host's resource usage.

NOTES:

• This policy doesn't perform optimization of VM allocation by means of VM migration.
• It has a low computational complexity but may return and inactive Host that will be activated, while there may be active Hosts suitable for the VM.

Since:

CloudSim Plus 1.0.0

Author:

Manoel Campos da Silva Filho

See Also:

• VmAllocationPolicyBestFit
• VmAllocationPolicySimple

Field Summary

Fields inherited from interface org.cloudbus.cloudsim.allocationpolicies.VmAllocationPolicy

DEF_HOST_COUNT_PARALLEL_SEARCH, LOGGER, NULL

Constructor Summary

Constructors

Constructor	Description
VmAllocationPolicyFirstFit()

Method Summary

Modifier and Type	Method	Description
protected Optional<Host>	defaultFindHostForVm(Vm vm)	Provides the default implementation of the policy to find a suitable Host for a given VM.
protected int	getLastHostIndex()	Gets the index of the last host where a VM was placed.
protected void	incLastHostIndex()	Increment the index to move to the next Host.

Methods inherited from class org.cloudbus.cloudsim.allocationpolicies.VmAllocationPolicyAbstract

allocateHostForVm, allocateHostForVm, allocateHostForVm, deallocateHostForVm, findHostForVm, getDatacenter, getHostCountForParallelSearch, getHostList, getOptimizedAllocationMap, isVmMigrationSupported, scaleVmVertically, setDatacenter, setFindHostForVmFunction, setHostCountForParallelSearch

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.cloudbus.cloudsim.allocationpolicies.VmAllocationPolicy

allocateHostForVm, allocateHostForVm, allocateHostForVm, deallocateHostForVm, findHostForVm, getDatacenter, getHostCountForParallelSearch, getHostList, getOptimizedAllocationMap, isParallelHostSearchEnabled, isVmMigrationSupported, scaleVmVertically, setDatacenter, setFindHostForVmFunction, setHostCountForParallelSearch

Constructor Details

VmAllocationPolicyFirstFit

public VmAllocationPolicyFirstFit()

Method Details

defaultFindHostForVm

protected Optional<Host> defaultFindHostForVm(Vm vm)

Description copied from class: VmAllocationPolicyAbstract

Provides the default implementation of the policy to find a suitable Host for a given VM.

Specified by:

defaultFindHostForVm in class VmAllocationPolicyAbstract

Parameters:

vm - the VM to find a suitable Host to

Returns:

an Optional containing a suitable Host to place the VM or an empty Optional if no suitable Host was found

See Also:

• VmAllocationPolicyAbstract.setFindHostForVmFunction(BiFunction)

getLastHostIndex

protected int getLastHostIndex()

Gets the index of the last host where a VM was placed.

incLastHostIndex

protected void incLastHostIndex()

Increment the index to move to the next Host. If the end of the Host list is reached, starts from the beginning.