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CloudSim Plus: A modern, highly extensible and easier-to-use Java 8 Framework for Modeling and Simulation of Cloud Computing Infrastructures and Services
/*
* Title: CloudSim Toolkit
* Description: CloudSim (Cloud Simulation) Toolkit for Modeling and Simulation of Clouds
* Licence: GPL - http://www.gnu.org/copyleft/gpl.html
*
* Copyright (c) 2009-2012, The University of Melbourne, Australia
*/
package org.cloudbus.cloudsim.provisioners;
import org.cloudbus.cloudsim.hosts.Host;
import org.cloudbus.cloudsim.resources.*;
import org.cloudbus.cloudsim.vms.Vm;
/**
* An interface that represents the provisioning policy used by a {@link Host}
* to provide a given physical resource to its {@link Vm}s.
*
* Each host must have its own instance of a ResourceProvisioner for each
* {@link Resource} it owns, such as {@link Ram}, {@link Bandwidth} (BW) and {@link Pe} (CPU).
*
* @author Rodrigo N. Calheiros
* @author Anton Beloglazov
* @author Manoel Campos da Silva Filho
* @since CloudSim Plus 1.0
* @todo There is a lot of confusion between Resource Allocation and Resource Provisioning.
* This article makes it clear: https://www.researchgate.net/post/what_is_the_difference_between_resource_allocation_and_resource_provisioning.
* Allocation is reservation, while Provisioning is actual usage of some part of the allocated resource.
* When a VM is created, the Host allocates resources, but the Host.allocateResourcesForVm
* uses ResourceProvisioners for that. More confusing yet, it calls vmScheduler.allocatePesForVm at the end.
* The terms allocation and provisioning sometimes are used in the same place.
* The Host.allocateResourcesForVm method has the word "allocate" in its name,
* while internally it uses ResourceProvisioners (quite confusing).
* VmScheduler is using the term "allocation", but since it's accountable for running a VM,
* it should perform resource provisioning (request the actual amount of the allocated resource to be used in that moment).
*/
public interface ResourceProvisioner {
/**
* An attribute that implements the Null Object Design Pattern for
* ResourceProvisioner objects.
*/
ResourceProvisioner NULL = new ResourceProvisionerNull();
/**
* Allocates an amount of the physical resource for a VM, changing the current capacity
* of the virtual resource to the given amount.
*
* @param vm the virtual machine for which the resource is being allocated
* @param newTotalVmResourceCapacity the new total amount of resource to allocate to the VM,
* changing the allocate resource to this new amount. It doesn't increase
* the current allocated VM resource by the given amount, instead,
* it changes the VM allocated resource to that specific amount
*
* @return $true if the resource could be allocated; $false otherwise
*/
boolean allocateResourceForVm(Vm vm, long newTotalVmResourceCapacity);
/**
* Allocates an amount of the physical resource for a VM, changing the current capacity
* of the virtual resource to the given amount.
*
* This method is just a shorthand to avoid explicitly converting
* a double to long.
*
* @param vm the virtual machine for which the resource is being allocated
* @param newTotalVmResource the new total amount of resource to allocate to the VM,
* changing the allocate resource to this new amount. It doesn't increase
* the current allocated VM resource by the given amount, instead,
* it changes the VM allocated resource to that specific amount
* @return $true if the resource could be allocated; $false otherwise
* @see #allocateResourceForVm(Vm, long)
*/
default boolean allocateResourceForVm(Vm vm, double newTotalVmResource){
return allocateResourceForVm(vm, (long)newTotalVmResource);
}
/**
* Gets the amount of resource allocated to a given VM from the physical resource
*
* @param vm the VM
*
* @return the allocated resource for the VM
*/
long getAllocatedResourceForVm(Vm vm);
/**
* Gets the total amount of resource allocated to all VMs from the physical resource
*
* @return the total allocated resource among all VMs
*/
long getTotalAllocatedResource();
/**
* Releases all the allocated amount of the resource used by a VM.
*
* @param vm the vm
* @return true if the resource was deallocated; false if the related resource
* has never been allocated to the given VM.
*/
boolean deallocateResourceForVm(Vm vm);
/**
* Releases all the allocated amount of the resource used by all VMs.
*/
void deallocateResourceForAllVms();
/**
* Checks if it is possible to change the current allocated resource for a given VM
* to a new amount, depending on the available physical resource remaining.
*
* @param vm the vm to check if there is enough available resource on the host to
* change the allocated amount for the VM
* @param newVmTotalAllocatedResource the new total amount of resource to allocate for the VM.
*
* @return true, if it is possible to allocate the new total VM resource; false otherwise
*/
boolean isSuitableForVm(Vm vm, long newVmTotalAllocatedResource);
/**
* Gets the resource being managed by the provisioner, such as {@link Ram}, {@link Pe}, {@link Bandwidth}, etc.
* @return the resource managed by this provisioner
*/
ResourceManageable getResource();
/**
* Sets the resource to be managed by the provisioner, such as {@link Ram}, {@link Pe}, {@link Bandwidth}, etc.
* @param resource the resource managed by this provisioner
*/
void setResource(ResourceManageable resource);
/**
* Gets the total capacity of the physical resource from the Host that the provisioner manages.
*
* @return the total physical resource capacity
*/
long getCapacity();
/**
* Gets the amount of free available physical resource from the host that the provisioner can allocate to VMs.
*
* @return the amount of free available physical resource
*/
long getAvailableResource();
/**
* Checks if the resource the provisioner manages is allocated to a given Vm.
* @param vm the VM to check if the resource is allocated to
* @return true if the resource is allocated to the VM, false otherwise
*/
boolean isResourceAllocatedToVm(Vm vm);
}