Virtual machine placement (VMP) problem has been a key issue in IaaS/PaaS cloud infrastructures. Many recent works on VMP prove that inter-VM relations such as memory share, traffic dependency and resource competition should be seriously considered to save energy, increase the performance of infrastructure, reduce service level agreement violation rates and provide better administrative capabilities to the cloud provider. However, most existing works consider the inter-VM relations without taking the heterogeneity of cloud data centers into account. In practice, heterogeneous physical machines (PM) in a heterogeneous data center are often partitioned into logical groups for load balancing and specific services, cloud users always assigned their VMs with specific PM requirements, which make the inter-VM relations far more complex. In this paper, we propose an efficient solution for VMP with inter-VM relation constraints in a heterogeneous data center. The experimental results prove that our solution can efficiently solve the complex problem with an acceptable runtime.

Mobile virtualization has emerged fairly recently and is considered a valuable way to mitigate security risks on Android devices. However, major challenges in mobile virtualization include runtime, hardware, resource overhead, and compatibility. In this paper, we propose a lightweight Android virtualization solution named Condroid, which is based on container technology. Condroid utilizes resource isolation based on namespaces feature and resource control based on cgroups feature. By leveraging them, Condroid can host multiple independent Android virtual machines on a single kernel to support mutilple Android containers. Furthermore, our implementation presents both a system service sharing mechanism to reduce memory utilization and a filesystem sharing mechanism to reduce storage usage. The evaluation results on Google Nexus 5 demonstrate that Condroid is feasible in terms of runtime, hardware resource overhead, and compatibility. Therefore, we find that Condroid has a higher performance than other virtualization solutions.