Dynamic application instance placement in data center environments

1. A method for new application instance placement in a set of machines under one or more resource constraints, the method comprising the steps of:

computing an estimate of a value of a first metric associated with a current application instance placement and a current application load distribution; and

determining the new application instance placement and a new application load distribution that optimizes the first metric, wherein the determining step further comprises:

the new application instance placement improving upon the first metric and the new application load distribution improving upon a second metric;

shifting an application load;

changing the current application instance placement without pinning to determine a first candidate placement;

changing the current application instance placement with pinning to determine a second candidate placement; and

selecting a best placement from the first candidate placement and the second candidate placement as the new application instance placement;

wherein the computing and determining steps are performed at least in part by a processor coupled to a memory.

2. The method of claim 1 , wherein the determining step is performed multiple times.

3. The method of claim 1 , further comprising the step of balancing an application load across the set of machines.

4. The method of claim 1 , wherein the first metric comprises a total number of satisfied demands.

5. The method of claim 1 , wherein the first metric comprises a total number of placement changes.

6. The method of claim 1 , wherein the first metric comprises an extent to which an application load is balanced across the set of machines.

7. The method of claim 1 , wherein one of the one or more resource constraints comprises a processing capacity.

8. The method of claim 1 , wherein one of the one or more resource constraints comprises a memory capacity.

9. The method of claim 1 , wherein the second metric comprises a degree of correlation between residual resources on each machine of the set of machines.

10. The method of claim 1 , wherein the second metric comprises a number of underutilized application instances.

11. Apparatus for new application instance placement in a set of machines under one or more resource constraints, the apparatus comprising:

a memory; and

at least one processor coupled to the memory and operative to: (i) compute an estimate of a value of a first metric associated with a current application instance placement and a current application load distribution; and (ii) determine the new application instance placement and a new application load distribution that optimizes the first metric, wherein the determining operation further comprises:

the new application instance placement improving upon the first metric and the new application load distribution improving upon a second metric;

shifting an application load;

changing the current application instance placement without pinning to determine a first candidate placement;

changing the current application instance placement with pinning to determine a second candidate placement; and

selecting a best placement from the first candidate placement and the second candidate placement as the new application instance placement.

12. An article of manufacture for new application instance placement in a set of machines under one or more resource constraints, comprising a non-transitory machine readable medium containing one or more programs which when executed implement the steps of:

computing an estimate of a value of a first metric associated with a current application instance placement and a current application load distribution; and

determining the new application instance placement and a new application load distribution that optimizes the first metric, wherein the determining step further comprises:

the new application instance placement improving upon the first metric and the new application load distribution improving upon a second metric

shifting an application load;

changing the current application instance placement without pinning to determine a first candidate placement;

changing the current application instance placement with pinning to determine a second candidate placement; and

selecting a best placement from the first candidate placement and the second candidate placement as the new application instance placement.