Although Cloud computing itself has many open problems, researchers in the field have already made the leap to envision Inter-Cloud computing. Their goal is to achieve better overall Quality of Service QoS, reliability and cost efficiency by utilizing multiple clouds. Inter-Cloud research is still in its infancy, and the body of knowledge in the area has not been well defined yet. In this work, we propose and motivate taxonomies for Inter-Cloud architectures and application brokering mechanisms. We present a detailed survey of the state of the art in terms of both academic and industry developments 20 projects, and we fit each project onto the discussed taxonomies. We discuss how the current Inter-Cloud environments facilitate brokering of distributed applications across clouds considering their nonfunctional requirements. Finally, we analyse the existing works and identify open challenges and trends in the area of Inter-Cloud application brokering. Copyright © 2012 John Wiley & Sons, Ltd.

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Inter-Cloud architectures and application brokering: taxonomy and survey

https://pureadmin.qub.ac.uk/ws/files/134629726/paper_v2.pdf

Next generation cloud computing

The landscape of cloud computing has significantly changed over the last decade. Not only have more providers and service offerings crowded the space, but also cloud infrastructure that was traditionally limited to single provider data centers is now evolving. In this paper, we firstly discuss the changing cloud infrastructure and consider the use of infrastructure from multiple providers and the benefit of decentralising computing away from data centers. These trends have resulted in the need for a variety of new computing architectures that will be offered by future cloud infrastructure. These architectures are anticipated to impact areas, such as connecting people and devices, data-intensive computing, the service space and self-learning systems. Finally, we lay out a roadmap of challenges that will need to be addressed for realising the potential of next generation cloud systems.

Next Generation Cloud Computing: New Trends and Research Directions

A brief review of the Internet history reveals the fact that the Internet evolved after the formation of primarily independent networks. Similarly, interconnected clouds, also called Inter-cloud, can be viewed as a natural evolution of cloud computing. Recent studies show the benefits in utilizing multiple clouds and present attempts for the realization of an Inter-cloud or federated cloud environment. However, cloud vendors have not taken into account cloud interoperability issues, and each cloud comes with its own solution and interfaces for services. This survey initially discusses all the relevant aspects motivating cloud interoperability. Furthermore, it categorizes and identifies possible cloud interoperability scenarios and architectures. The spectrum of challenges and obstacles that the Inter-cloud realization is faced with are covered, a taxonomy of them is provided, and fitting enablers that tackle each challenge are identified. All these aspects require a comprehensive review of the state of the art, including ongoing projects and studies in the area. We conclude by discussing future directions and trends toward the holistic approach in this regard.

http://romisatriawahono.net/lecture/rm/survey/network%20security/Toosi%20-%20Interconnected%20Cloud%20Computing%20Environments%20-%202014.pdf

Interconnected Cloud Computing Environments: Challenges, Taxonomy, and Survey

We study the virtual machine live migration (LM) and disaster recovery (DR) from a networking perspective, considering long-distance networks, for example, between data centers. These networks are usually constrained by limited available bandwidth, increased latency and congestion, or high cost of use when dedicated network resources are used, while their exact characteristics cannot be controlled. LM and DR present several challenges due to the large amounts of data that need to be transferred over long-distance networks, which increase with the number of migrated or protected resources. In this context, our work presents the way LM and DR are currently being performed and their operation in long-distance networking environments, discussing related issues and bottlenecks and surveying other works. We also present the way networks are evolving today and the new technologies and protocols (e.g., software-defined networking, or SDN, and flexible optical networks) that can be used to boost the efficiency of LM and DR over long distances. Traffic redirection in a long-distance environment is also an important part of the whole equation, since it directly affects the transparency of LM and DR. Related works and solutions both from academia and the industry are presented.

Survey: Live Migration and Disaster Recovery over Long-Distance Networks

http://srijith.net/publications/confs/UCC_2010.pdf

OPTIMIS: A holistic approach to cloud service provisioning

Despite the widespread support for live migration of Virtual Machines (VMs) in current hypervisors, these have significant shortcomings when it comes to migration of certain types of VMs. More specifically, with existing algorithms, there is a high risk of service interruption when migrating VMs with high workloads and/or over low-bandwidth networks. In these cases, VM memory pages are dirtied faster than they can be transferred over the network, which leads to extended migration downtime. In this contribution, we study the application of delta compression during the transfer of memory pages in order to increase migration throughput and thus reduce downtime. The delta compression live migration algorithm is implemented as a modification to the KVM hypervisor. Its performance is evaluated by migrating VMs running different type of workloads and the evaluation demonstrates a significant decrease in migration downtime in all test cases. In a benchmark scenario the downtime is reduced by a factor of 100. In another scenario a streaming video server is live migrated with no perceivable downtime to the clients while the picture is frozen for eight seconds using standard approaches. Finally, in an enterprise application scenario, the delta compression algorithm successfully live migrates a very large system that fails after migration using the standard algorithm. Finally, we discuss some general effects of delta compression on live migration and analyze when it is beneficial to use this technique.

Evaluation of delta compression techniques for efficient live migration of large virtual machines

Recent developments in virtualisation technology have resulted in its proliferation of usage across datacentres. Ultimately, the goal of this technology is to more efficiently utilise server resources to reduce Total Cost of Ownership (TCO) by abstracting hardware and consolidating servers. This results in lower equipment costs and less electrical consumption for server power and cooling. However, the TCO benefits of holistic virtualisation extend beyond server assets. One of these aspects relates to the ability of being able to migrate Virtual Machines (VM) across distinct physical hosts over a network. However, limitations of the current migration technology start to appear when they are applied on larger application systems such as SAP ERP or SAP ByDesign. Such systems consume a large amount of memory and cannot be transferred as seamlessly as smaller ones, creating service interruption. Limiting the impact and optimising migration becomes even more important with the generalisation of Service Level Agreement (SLA). In this document we present our design and evaluation of a system that enables live migration of VMs running large enterprise applications without severely disrupting their live services, even across the Internet. By combining well-known techniques and innovative ones we can reduce system down-time and resource impact for migrating live, large Virtual Execution Environments.

Improving the live migration process of large enterprise applications

Virtualization technology provides a means for server consolidation, reducing the number of physical servers required for running a given workload. Virtual Machine (VM) live migration facilitates the transfer of a running (VM) between physical hosts while appearing transparent to the running application. Memory intensive applications tend to obstruct the original pre-copy live migration process and may result in the failure of the migration process due to its inability to transfer memory faster than memory is dirtied by the running application. The focus of this paper is to present several techniques that can be applied to both pre-copy live migration and post-copy live migration to better support migration of memory intensive applications.

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Pre-Copy and post-copy VM live migration for memory intensive applications

Operating parameters of one or more software appliances may be set at a configuration manager. Compliance of the one or more software appliances with license terms may be maintained at a license manager. Communications may be executed between the license manager and the configuration manager to maintain compliance of the operating parameters with the license terms. A user interface may be provided for administration of the one or more software appliances therewith, the administration including deployment of the one or more software appliances, the license manager, the configuration manager, and a deployment manager within a system landscape. Communication may be executed between the license manager and the deployment manager to maintain compliance of the administration of the one or more software appliances with the license terms. Communication may be executed between the deployment manager and the configuration manager to manage the deployment relative to the operating parameters.

Benoit Hudzia

Papers

OPTIMIS: A holistic approach to cloud service provisioning

Evaluation of delta compression techniques for efficient live migration of large virtual machines

Improving the live migration process of large enterprise applications

Pre-Copy and post-copy VM live migration for memory intensive applications

Flexible appliance hosting with coordination of deployment, licensing and configuration