Dynamic Placement of Virtual Machines with Both Deterministic and Stochastic Demands for Green Cloud Computing

Algorithm 1

The procedures to judge whether a PM ℎ_𝑖 is a candidate for server consolidation.

Procedure MigPlan = JudgeMigratable (ℎ_𝑖)

(1) Initialize 𝑆_𝑡(ℎ_𝑖) as the set of VMs on server ℎ_𝑖 at time instant 𝑡

(2) 𝑛←𝑆_𝑡(ℎ_𝑖). size

(3) for  𝑘=1 to 𝑛  do

(4)   According to MEAGLE, search for the Host(𝑣_𝑘) for 𝑣_𝑘, where 𝑣_𝑘∈𝑆_𝑡(ℎ_𝑖).

(5)   if  Host(𝑣_𝑘)∈𝑃₁⧵{ℎ_𝑖}

(6)      MigPlan = [MigPlan; 𝑣_𝑘ℎ_𝑖 Host(𝑣_𝑘)]

(7)      Update the usage state of Host(𝑣_𝑘) after 𝑣_𝑘 is placed on it.

(8)  else

(9)      𝑙←𝑘;

(10)      𝑛count←𝑛count+1

(11)      if  𝑛count>1

(12)       /*In 𝑆_𝑡(ℎ_𝑖), there exists more than one VM without directly-deployed servers.

(13)        MigPlan=[];

(14)        return  MigPlan

(15)       end  if

(16)  end  if

(17) end  for

(18) if  𝑛count==1

(19)  /*In 𝑆_𝑡(ℎ_𝑖), there is only one VM 𝑣_𝑙 without directly-deployed servers.

(20)   if  ∃ℎ₁, ℎ₂∈𝑃₁⧵{ℎ_𝑖}, 𝑣_𝑙 can be placed on ℎ₁

    after an original VM on ℎ₁ is migrated into ℎ₂, then

(21)      Update MigPlan

(22)  else  if  ∃ℎ₁, ℎ₂, ℎ₃∈𝑃₁⧵{ℎ_𝑖}, 𝑣_𝑙 can be placed on ℎ₁

   after two original VMs on ℎ₁ are respectively migrated into ℎ₂ and ℎ₃, then

(23)     Update MigPlan

(24)   else  if  ∃ℎ₁, ℎ₂∈𝑃₁⧵{ℎ_𝑖}, 𝑣_𝑙 can be placed on ℎ₁

    after an original VM on ℎ₁ is exchanged with a VM on ℎ₂, then

(25)    Update MigPlan

(26)   else

(27)    MigPlan=[]

(28)    return MigPlan

(29)   end  if

(30) end  if

(31) return  MigPlan