Schedule virtual machines

1. A computer-implemented method comprising:

receiving virtual machine (VM) requests;

establishing a baseline resources that fall within a variance limit;

determining at least one irregular VM request in the VM requests, responsive to comparing the at least one irregular VM request to a baseline VM request, the baseline VM request being associated with the baseline resources;

finding a combination of the at least one irregular VM request and one or more VM requests of the VM requests that optimizes available resources of a candidate host machine to combine requested resources of the at least one irregular VM request and the one or more VM requests; and

allocating the at least one irregular VM request and the one or more VM requests to the candidate host machine.

2. The computer-implemented method of claim 1 , wherein the finding is configured to match the combined requested resources of the at least one irregular VM request and the one or more VM requests with the available resources of the candidate host machine while ensuring that any unused resources in the candidate host machine satisfy a possibility of allocating at least one future VM request to the candidate host machine.

3. The computer-implemented method of claim 2 , wherein future requested resources of the at least one future VM request are based on the baseline VM request.

4. The computer-implemented method of claim 1 , wherein the finding is configured to match the combined requested resources with the available resources of the candidate host machine while ensuring that either no unused resources remain on the candidate host machine or that any unused resources in the candidate host machine satisfy a possibility of allocating at least one future VM request to the candidate host machine.

5. The computer-implemented method of claim 1 , wherein the finding comprises using a global optimization to find a best matched host machine from a plurality of candidate host machines.

6. The computer-implemented method of claim 1 , further comprising determining irregular VM requests in the VM requests based on a comparison to the baseline VM request;

finding a combination of the irregular VM requests that optimizes available resources of a potential host machine and requested resources of the irregular VM requests; and

allocating the combination of the irregular VM requests to the potential host machine.

7. The computer-implemented method of claim 6 , wherein the finding is configured to match the requested resources of the combination of the irregular VM requests with the available resources of the potential host machine while ensuring that any unused resources in the potential host machine satisfy a possibility of allocating at least one future VM request to the potential host machine; and

wherein the requested resources of an irregular VM request in the irregular VM requests differ from baseline requested resources associated with the baseline VM request.

8. The computer-implemented method of claim 1 , further comprising determining available resource ratios for types of available resources in a group of two or more host machines;

determining differences among the available resource ratios for the group; and

determining whether or not to migrate one or more VMs in the group based on the differences.

9. A system comprising:

a memory having computer readable instructions; and

one or more processors for executing the computer readable instructions, the computer readable instructions controlling the one or more processors to perform operations comprising:

receiving virtual machine (VM) requests;

establishing a baseline resources that fall within a variance limit;

determining at least one irregular VM request in the VM requests, responsive to comparing the at least one irregular VM request to a baseline VM request, the baseline VM request being associated with the baseline resources;

finding a combination of the at least one irregular VM request and one or more VM requests of the VM requests that optimizes available resources of a candidate host machine to combine requested resources of the at least one irregular VM request and the one or more VM requests; and

allocating the at least one irregular VM request and the one or more VM requests to the candidate host machine.

10. The system of claim 9 , wherein the finding is configured to match the combined requested resources of the at least one irregular VM request and the one or more VM requests with the available resources of the candidate host machine while ensuring that any unused resources in the candidate host machine satisfy a possibility of allocating at least one future VM request to the candidate host machine.

11. The system of claim 10 , wherein future requested resources of the at least one future VM request are based on the baseline VM request.

12. The system of claim 9 , wherein the finding is configured to match the combined requested resources with the available resources of the candidate host machine while ensuring that either no unused resources remain on the candidate host machine or that any unused resources in the candidate host machine satisfy a possibility of allocating at least one future VM request to the candidate host machine.

13. The system of claim 9 , wherein the finding comprises using a global optimization to find a best matched host machine from a plurality of candidate host machines.

14. The system of claim 9 , further comprising determining irregular VM requests in the VM requests based on a historical profilea comparison to the baseline VM request;

finding a combination of the irregular VM requests that optimizes available resources of a potential host machine while seeking to minimize differences between the combination and requested resources of the irregular VM requests and the potential host machine; and

allocating the combination of the irregular VM requests to the potential host machine.

15. The system of claim 14 , wherein the finding is configured to match the requested resources of the combination of the irregular VM requests with the available resources of the potential host machine while ensuring that any unused resources in the potential host machine satisfy a possibility of allocating the at least one future VM request to the potential host machine; and

wherein the requested resources of an irregular VM request in the irregular VM requests differ from baseline requested resources associated with the baseline VM request.

16. The system of claim 9 , further comprising determining available resource ratios for types of available resources in a group of two or more host machines;

determining differences among the available resource ratios for the group; and

determining whether or not to migrate one or more VMs in the group based on the differences.

17. A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to perform operations comprising:

receiving virtual machine (VM) requests;

establishing a baseline resources that fall within a variance limit;

determining at least one irregular VM request in the VM requests, responsive to comparing the at least one irregular VM request to a baseline VM request, the baseline VM request being associated with the baseline resources;

finding a combination of the at least one irregular VM request and one or more VM requests of the VM requests that optimizes available resources of a candidate host machine while accounting for possible allocation of a least one future VM request to the candidate host machine based on the baseline VM request; and allocating the at least one irregular VM request and the one or more VM requests

to the candidate host machine.

18. The computer program product of claim 17 , wherein the finding is configured to match combined requested resources of the at least one irregular VM request and the one or more VM requests with the available resources of the candidate host machine while ensuring that any unused resources in the candidate host machine satisfy a possibility of the at least one future VM request.