Virtual machine placement for minimizing connection cost in data center networks

Virtualization is a key technology for the efficient operation of massive data centers. To minimize the communication costs among virtual machines (VMs) in a data center network, we formulate an optimization problem for finding efficient VM placements. In this problem, a set of requests is received from customers, where each request is defined as the required number of VMs. The problem seeks to determine those physical machines in the network that host the requested VMs under a capacity constraint such that the number of VMs placed on each physical machine does not exceed that of the available slots. To minimize the load of the networks, for each request, we consider the connection cost of the VM placements, which is defined as the minimum length of networks connecting all physical host machines and the root node. The objective in the problem is to minimize the total connection costs. We present an approximation algorithm for this optimization problem.