0.9.6 - More elaborate IaaSService, VMSchedulers, DeferredEvents and ResourceConstraints

The third github release of the DISSECT-CF simulator

List of changes since 0.9.5:

Major changes:

• IaaSService improvements:
  • Initial implementation of IaaS energy meter as an aggregation of PM meters.
  • VM request termination possibility (allows a VM without a resource allocation to be dropped from the VM scheduler's queue)
  • VM listing now includes VMs that are only queued but not yet deployed on the system
• Major overhaul of VM schedulers
  • Introduction of PM Iterators
  • Allowing simplified implementations (by allowing to take more code from FirstFit)
  • Minimally improving scheduling performance
  • Introduction of RandomScheduler
  • When a schedule is done one can now report how much resources need to be freed up in order to fulfill the next queued item
  • In some heavily queued situations this approach improves performance significantly
  • The first fit scheduler implementation now calculates this value to demonstrate this behavior
• Introduction of the direct consumer in Physical Machines
  • Allows the simulation of VMM related operations
  • Provides better simulation of boot and shutdown procedures
• Resource constraints are not constant anymore
  • introduction of Alterable/Constant and Constraint propagators
  • It is now more apparent if a constraint cannot change
• DeferredEvents are now handled in batches
  • Improves performance for unrelated but simultaneous deferred events
  • Improves performance of serial unsubscrptions done by releasing resource allocations by the VM Schedulers
• Introduction of the StateDependentEventHandler
  • A new (time-independent) event handling mechanism
  • useful for PM/VM state change monitoring etc.

Minor changes:

• Repositories now allow storing from/to memory instead of only from/to other repositories
  • Allows better simulation of initial data deposits
• Introduction of the MultiPMController
  • if the VM queue suddenly becomes crowded, then this controller switches on many machines
• Bug fixes:
  • In some cases influence groups were created improperly causing exceptions in Timed (see the ResourceSpreadingTest.groupManagement() test case).
  • Class cast exception was thrown during resource consumption registration if the consumer was not a VirtualMachine but the producer was a PhysicalMachine. (see the more elaborate PhysicalMachine.isAcceptableConsumption function)
  • PM Switchoff handling (removing unnecessary delays caused by not yet dropped but finished resource consumptions)
  • The skipEventsTill function works correctly for 0 frequency events as well as for time jumps that would lead to the past
  • Floating point handling issues could lead the MaxMinFairSpreader to raise an IllegalStateException in the ResourceConsumption's realLimit handling procedures.
  • During the dependency group management references to some no longer used resource spreaders were unnecessarily held (causing some memory leakage)
  • Resource Allocations are now released even if the VM implementation does not do the release.
  • Several unnecessary references were kept to all VMs, these were dropped to reduce the memory pressure of the system.
  • The base VM scheduler was calling its subclasses for scheduling on every PM's addition despite there was no queued VM.
• Improved readme for new users
• Improved test coverage

New dependencies:

• trove (for efficient arrays and maps with primitive types)
• apache-commons-lang (for simple Array management)

0.9.5: focused on under provisioning and energy metering

The second github release of the DISSECT-CF simulator.

List of changes since 0.9.4:

Major changes:

• Improved EnergyMetering behaviour (better handling of metering start stop events, aggregated and indirect metering possibilities)
• Allowing the user of the simulator to use arbitrary length of time for time base (we are no longer using ms as the fixed base)
• Support for under provisioned VMs by introducing processing power independent resource constraints

Minor changes:

• Improved VM request queueing mechanisms to allow better VM schedulers
• Improved VM-PM scheduler interfacing
• New RoundRobin VM scheduler
• Performance optimizations
  • Including optimizations from @scsaba01
• Now includes minimal documentation. More to come.

The first github release - somewhat stable

Features:

• Basic IaaS functionalities
• VM and PM scheduling constructs and minimal working examples
• Resource sharing modeling (for network, disk and CPU with Max Min fairshare)
• Modelling of Physical and Virtual Machine interactions
• Complex VM state modelling
• Resource level power metering capabilities to allow complex consumption analysis
• Multi cloud simulation