2014 OpenNebula Cloud Architecture Survey Results

Executive Summary

The results of this survey were collected during July and August of 2014 from the OpenNebula open source cloud management platform community with regards to the type of cloud deployment and its main architectural components. The aim of the survey is to acquire information in order to improve the support for the most demanded infrastructure platforms and deployments.

Since the foundation of the open-source project in November 2007, OpenNebula has been downloaded more than 200,000 times from the project site (120,000 times since our last survey in September 2012), not including other software repositories or third-party distributions.

Regarding the use of OpenNebula, the Survey shows that 42% of the deployments are in Industry and 14% in Research Centers. 74% of the organizations are in Europe, Russia or USA. 88% of the respondents use OpenNebula to build a private cloud. When asked about the type of workload, 62% said that they use OpenNebula for running production workloads.

Regarding the size of the clouds, 10% of the deployments have more 500 physical nodes. 44% of the deployments consist of more than one OpenNebula zone and 4% are running more than 10 zones. One of the companies reported a workload of 200,000 VMs. Among the advanced components offered by OpenNebula, High Availability, with 67%, is the most widely used or planned to use, which is closely aligned with the top usage of OpenNebula in production environments.

Regarding the building blocks of the cloud, KVM at 48% and VMware at 30% are the dominant hypervisors, and CentOS at 46% and Ubuntu at 36% are the most widely used linux distributions for OpenNebula clouds. The preferred choices for the storage back-ends are shared FS and SSH with a 52% and 36% ratio respectively. The most widely used Configuration Management Systems are Puppet and Ansible with a 37% and 14% respectively. Regarding networking, most of the deployments, a 49%, use the Standard Linux Bridge for network configuration, 38% use Open vSwitch, and 30% use 802.1Q.

In comparison to the previous survey findings in 2012, the relevant changes are that CentOS has displaced Ubuntu as the most widely linux distribution to build OpenNebula clouds, and a growth in the number of production deployments from 42% to 62% and in the number of public clouds that has doubled from 21% to 40%.

Although more than 2,000 users took part of the survey, we have only included in the analysis those respondents using OpenNebula 4.x (latest series) and who we deem reliable because they have provided identification details that allow us to verify the answers of the survey. This is important given that our main aim is to have accurate and useful information about OpenNebula deployments.

Last, but not least, when asked about what you like most about OpenNebula, most users, a 76%, answered because of its simplicity, and 69% and 65% answered because of its flexibility and openness. These results are aligned with our our mission — to become the simplest cloud enabling platform — and our purpose — to bring simplicity to the private and hybrid enterprise cloud. OpenNebula exists to help companies build simple, cost-effective, reliable, open enterprise clouds on existing IT infrastructure.

BIG THANKS to all the organizations that have contributed to the survey!

A. About the Organization

42% of the respondents indicated that they work for industry, while 14% work for research centers.

Type_of_OrganizationType of Organization

 

54% of the deployments are in Europe and Russia. This means a small increase compared with previous survey where the number of deployments in Europe and Russia was 49%. 80% of the respondents are located in Europe, Russia, North America, China, Japan or Korea.

2_Geographic_RegionGeographic Region

 

63% of the organizations are small companies with fewer than 100 employees, and only 5% has more than 10,000 employees.

3_EmployeesNumber of Employees in the Organization

B. About the Cloud

88% of the respondents are running a private cloud for internal operations, while 40% are running a public cloud to offer utility services. Compared with 2012, the number of public clouds has doubled from 21%. This is aligned with the quickly growing number of hosting companies that are adopting OpenNebula to offer cloud services.

4_Cloud_TypeType of Cloud (people may select more than one checkbox)

 

76% of the respondents are running a non-critical environment or peripheral installations for running testing or development applications, while 62% are using the cloud for running production workloads. The number of production deployments has grown from 42% in 2012.

5_Workload_TypeType of Workload (people may select more than one checkbox)

 

The number of users in most of the clouds, a 71%, is fewer than 100. Many of these deployments use OpenNebula as virtual data center infrastructure manager and not as a cloud provisioning platform.

6_Number_of_UsersNumber of Users

C. About the Cloud Architecture

52% of the OpenNebula deployments have more than 10 nodes, and 10% of the deployments have more than 500 physical nodes. The number of very large-scale deployments has slightly fallen from 13% achieved in 2012.

6_Number_of_UsersNumber of Nodes

 

44% of the deployments consist of more than one OpenNebula zone, and 4% are running more than 10 zones.

8_Number_of_ZonesNumber of Zones

 

KVM at 48% and VMware at 28% are the most widely used hypervisors. Next one is Xen at 11%. Hyper-V and Xen Cloud Platform usage has fallen from a 11% in 2012 to a 4%, mostly because these two hypervisors are not supported by the OpenNebula distribution. They can be used through community plugins.

9_HypervisorsHypervisor  (people may select more than one checkbox)

 

52% of the OpenNebula deployments use a shared file system; 36% of users use the ssh datastore; 30% use VMware FS; and 42% of the users use a block device architecture based on LVM or iSCSI. GlusterFS and Ceph are used by 18% and 17% of the organizations respectively.

10_StorageStorage Configuration  (people may select more than one checkbox)

 

Most of the deployments, a 49%, use the Standard Linux Bridge for network configuration; 38% uses Open vSwitch; and 30% uses 802.1Q.

11_NetworkNetwork Configuration  (people may select more than one checkbox)

 

92% of the clouds use the monitoring system provided by OpenNebula, and 37% use a third-party monitoring system.

12_MonitoringMonitoring Configuration  (people may select more than one checkbox)

 

Regarding authentication, most of the organizations, a 65%, are using the built-in user/password system, while SSH and LDAP, with 43% and 27%, are the more popular external authentication systems.

13_AuthenticationAuthentication Configuration  (people may select more than one checkbox)

 

CentOS at 46% and Ubuntu at 36% are the most widely used linux distributions for building OpenNebula clouds. In the previous survey in 2012, Ubuntu was the most widely used with a 31%. Notice that in this last survey we allowed respondents to select more than one operating system.

14_Operating_SystemOperating System  (people may select more than one checkbox)

 

Puppet is used by 37% of the OpenNebula users. 37% have reported that they do not use any Configuration Management Systems (CMS) as the existing OpenNebula contextualization system and cloud-init support meet their needs. Ansible ,with a 14%, is the next popular CMS within the OpenNebula community.

15_CMS

Configuration Management System  (people may select more than one checkbox)

 

Among the advanced components offered by OpenNebula, High Availability, with a 67%, is the most widely used or planned to use. Flow multi-VM and DC federation are the next features with a 46%.

16_Advanced_ComponentsAdvanced Components (people may select more than one checkbox)

D. Why OpenNebula

Basically OpenNebula is used for its simplicity, flexibility, and openness.

17_Why_OpenNebulaWhy OpenNebula (people may select more than one checkbox)

 

OpenNebula Integrates with Azure to Build Hybrid Clouds

Today we are sharing exciting news about the expansion of the number of public clouds supported by OpenNebula to build hybrid cloud deployments. As a result of the collaboration between OpenNebula and Microsoft, a new set of plug-ins to support Microsoft Azure has been included in OpenNebula. This partnership has been announced today by Microsoft Open Technologies at the O’Reilly Open Source Convention (OSCON).

“With this set of plug-ins, IT pros and system integrations can use OpenNebula’s rich set of infrastructure management tools to manage cloud deployments across Microsoft’s private, public and hosted cloud platforms.”

The Beta version of  OpenNebula 4.8 bringing the new drivers was released today and is available for testing. The integration has been carried out using the Microsoft Azure SDK for Ruby, which interacts with the Azure REST API, enabling a complete control of the lifecycle of Virtual Machines in a transparent way within an OpenNebula cloud. Thanks to these new plug-ins, private resources can be easily supplemented with resources from Azure to meet fluctuating demands.

So far the only public cloud officially supported by OpenNebula to build hybrid cloud deployments was Amazon AWS. Supporting multiple public cloud providers opens the possibility of defining pre-determined schedule or performance-based policies for the execution of applications in different clouds, that can be fine tuned to achieve an optimal placement in terms of performance and cost. This new support also enables the ability to meet services constraints regarding special functionality offered by a subset of the supported public cloud providers, like for instance high availability.

Need more information? You are welcome to use the OpenNebula community instruments to ask around (for instance, the users mailing list is a good place to pose your questions).

As always, we value your feedback and contributions to this new feature!

New User Survey: Please Help Us Meet Your Needs!

We have created a new user survey that will take you only 5 minutes to complete. As an open-source community, it is very important for us to have information about your deployment. Doing so you will have influence over the project and software direction, and will help us improve the support for most demanded infrastructure platforms and configurations.

All of the information you provide is confidential. We will not share organization-specific or personal information. We will only report aggregate, non-personally identifiable data.

The results from our last survey  (2012) are available here. Do not hesitate to contact us if you have questions.

 

Thanks for completing the survey!

About Simplicity, Openness, Reliability and Flexibility in Private Cloud Computing

We feel it’s time to remind our vision of a world that won’t be dominated by a single cloud management platform. We’re moving into a world of open cloud — where each organization can find the right cloud for its unique needs. A single cloud management platform can not be all things to all people, there will be a cloud space with several offerings focused on different environments and/or industries. This is the natural evolution, same happened in other markets like relational databases or the web servers.

Our commitment to the open cloud flows directly out of our mission — to become the simplest cloud enabling platform — and our purpose — to bring simplicity to the private and hybrid enterprise cloud. OpenNebula exists to help companies build simple, cost-effective, reliable, open enterprise clouds on existing IT infrastructure, where:

Simplicity means …

… you do not need an army of administrators to build and maintain your cloud.

Openness means …

… you will run production-ready software that is fully open-source without proprietary extensions that lock you in.

Reliability means …

… your cloud will run for years with little maintain.

Flexibility means …

… you can easily build a cloud to fit into your data center and policies.

 

Looking for Alternatives to vCloud for your VMware Infrastructure?

Many companies contact us because they are looking for alternatives to VMware vCloud. They usually report that:

  • vCloud is not an easy to use solution
  • vCloud is mostly suited for vSphere and public clouds running VMware
  • vCloud can no be adapted to their needs
  • Last, but not least, VMware announced in september 2013 that vCloud Director was approaching end of life for enterprises with its functionality being split into vCenter and vCloud Automation Center

Because it is completely hypervisor agnostic, fully supports VMware, and is easy to install, maintain and use within existing VMware environments, OpenNebula is widely used as an open alternative to VMware vCloud at significantly lower costs. Some of our users also see OpenNebula as a migration tool that allows them to perform a smooth transition from VMware to more open hypervisor alternatives like KVM. In other words OpenNebula leverages existing VMware infrastructure, protecting IT investments, and at the same time avoids future vendor lock-in, strengthening the negotiating position of the enterprise.

Companies usually evaluate other alternatives, like some of the OpenStack-based products, Red Hat’s mainly. In these cases, we suggest the company to:

  • Compare features and see which product is closer to vCloud in terms of enterprise cloud features
  • Ask the other providers if they offer enterprise support for both VMware and KVM (or any other open-source hypervisor)
  • Check if the other products are really open-source or a proprietary extension of a open-source software

Finally, companies need to develop a hybrid cloud strategy. We understand private cloud as a complement to public cloud, and this is why we provide unique features to build hybrid cloud deployments. OpenNebula offers a single management interface for internal and remote cloud resources.

So before starting the migration from vCloud to vCAC, why do not you give a try to OpenNebula to manage your cloud platform?. Our community is willing to help you.

OpenNebula Collaborates with IBM Softlayer in Hybrid Cloud Computing

OpenNebula features unique functionality for virtualization of the datacenter. Among them, it is worth highlighting its support to build cloud bursting architectures where private cloud resources can be easily supplemented with resources from a remote public cloud to meet fluctuating demands. The reason behind this uniqueness is the transparency to use and maintain the cloud bursting functionality for both end users and cloud administrators.

The latest version of OpenNebula, Carina, offers a simple but comprehensive framework that enables resource allocation to different groups of users in federated data centers and hybrid cloud deployments. OpenNebula offers a single management point for both local private and remote public cloud resources, with an end user self-service portal (Cloud View) that enables the consumption of hybrid virtual machine templates. These hybrid templates are intended to define identical virtual machines -in terms of provided service- whether they get deployed in the local infrastructure using local resources, or if the scheduler decides to deploy them remotely in a public cloud provider.

So far the only public cloud officially supported by OpenNebula to build hybrid cloud deployments is Amazon AWS. During the last months, several of our main users have demanded support for other commercial providers to be able to manage workloads across different clouds. Driven by this user demand, we have started discussions with the main public cloud providers in order to collaborate with them in their integration with OpenNebula. Supporting multiple public cloud providers would open the possibility of defining pre-determined schedule or performance-based policies for the execution of applications in different clouds, that can be fine tuned to achieve an optimal placement in terms of performance and cost. This support will also enable the ability to meet services constraints regarding special functionality offered by a subset of the supported public cloud providers, like for instance high availability.

 

Hybrid Cloud Computing with OpenNebula and SoftLayer

Hybrid Cloud Computing with OpenNebula and SoftLayer

We are really excited to announce that C12G Labs has started a collaboration with IBM in order to develop a new hybrid plugin for the Softlayer cloud. IBM Softlayer is providing support and technical guidance to OpenNebula open-source project to add and maintain Softlayer in the list of officially supported public clouds. Softlayer adoption is rising fast and its support to build OpenNebula-based hybrid clouds is highly demanded by some of our biggest users. The results of this collaboration will be incorporated into the OpenNebula distribution under the Apache license and, as such, it will be available freely to the public. The OpenNebula team will start forging the integration in a few days and are planning to incorporate a first version of the integration in the next release of OpenNebula scheduled for July 2014.

This collaboration consolidates OpenNebula’s position as the open-source platform of choice in the converged data centre, providing a simple, albeit flexible and powerful, cloud manager that supports traditional IT features such as fault tolerance and failover; the dynamic provisioning, elasticity and multi-tenancy of modern enterprise clouds; and connectors for external clouds.

Need more information? You are welcome to use the OpenNebula community instruments to ask around (for instance, the users mailing list is a good place to pose your questions). Moreover, if you are in the US this June, you can register in the upcoming OpenNebula TechDay events in Boca Raton, Florida, on June 19th, hosted by TransUnion|TLOxp -global leader in information and risk management- and in Fremont, California, on June 24th, hosted by Hyve Solutions, a leader in providing large scale deployments and an original Open Compute solutions provider.

This is excellent news for the community!

Eucalyptus and OpenNebula: Pioneers in Private Cloud Technology

The IEEE Transactions on Cloud Computing Journal is publishing a paper entitled “A Scientometric Analysis of Cloud Computing Literature” that presents an analysis of publication patterns, research impact and research productivity in the field of Cloud Computing. The following 2009 articles, which presented the original internal design and architecture of the Eucalyptus and OpenNebula cloud management platforms,

  • “Nurmi D., Wolski R., Grzegorczyk C., Obertelli G., Soman S., Youseff L., Zagorodnov D. (2009) The eucalyptus open-source cloud-computing system. In: 9th IEEE/ACM International Symposium on Cluster Computing and the Grid, CCGRID 2009, pp. 124-131”, and
  • “Sotomayor B., Montero R.S., Llorente I.M., Foster I. (2009) Virtual infrastructure management in private and hybrid clouds. IEEE Internet Computing 13(5):14-22.”

are in fourth and seventh position, respectively, of the top cited publications in cloud computing. This demonstrates the pioneering work done by these two well-known and widely-used open-source projects and the maturity of their open-source products.

About How OpenNebula is Enabling Business in the Cloud

This week we gave an invited talk in the open-source cloud session at Future Internet Assembly 2014. Its aim was to show how OpenNebula is driving innovation in cloud computing, impacting the adoption of private cloud, and enabling business in the cloud.

We covered the following scenarios:

  • First, most organizations adopt cloud to optimize their IT investment, to improve existing services or to support new business and service models. In this scenario, OpenNebula lowers the barriers for new organizations to build their private cloud.
  • Second, many organizations like the fact that open source allows great customization to meet individual requirements. They can build a differentiated cloud service to meet customers needs or to offer new cloud provision models for a specific market segment or geography.
  • Third, open-source also encourages and supports innovation in the development of new cloud products. We have seen many examples of how its use lowers the barriers for new ICT players to create their own cloud offerings.

We wanted to present experiences from users, so we included some details about how OpenNebula is being used by four Europe companies. Big thanks to Armin Deliomini (Runtastic), Stefan Kooman (BIT.nl), Carlo Daffara (CloudWeabers) and Bernd Erk (Netways)!.
IMAG0432

Balance between User Base and Community in OpenStack and OpenNebula

In our last post “OpenNebula vs. OpenStack: User Needs vs. Vendor Driven” we stated that “OpenStack penetration in the market is relatively small compared with the investment made by vendors and VCs”. We have received several emails from people asking for the numbers that support this statement. This conclusion arises from the comparison between OpenNebula and OpenStack user base, a well as between the resources invested in development and marketing by each of them.

User Base

OpenStack is experiencing explosive growth in the number of developers, with more than 200 companies contributing code, 15,000 people and 850 companies involved according to its web site, and almost 1,000 developers involved in its latest release. However, the number of users and the size of the deployments are not that impressive, at least compared with this software development force.

Let us compare the user base of OpenNebula and OpenStack by using their latest surveys:

  • According to the most recent OpenStack user survey (November 2013), they received 827 responses, and 387 were deployments. In the 80% of these deployments the number of nodes was below 100, and only 11 deployments with more than 1,000 nodes (hypervisors).
  • On the other hand, in the latest OpenNebula survey (November 2012), OpenNebula received 2,500 responses, 820 of these were deployments. In the 70% of these deployments the number of nodes was below 100 nodes, and 99 deployments have more than 500 nodes (hypervisors).

nodes

We avoid giving references to featured users, both projects could put on the table good references of large-scale cloud deployments. The surveys show that OpenNebula and OpenStack are achieving a similar level of deployment. However, OpenStack presents a ratio 1/40 between deployments in the survey and number of people involved, a ratio 1/3 between deployments and developers, and a ratio 1/2 between deployments and companies involved. Not every company contributed to the survey?.

We could also use the volume of web searches according to Google Trends to compare the impact of both projects. The ratio in the number of searchers between OpenNebula and OpenStack during the last 12 years is 1/20. This mainly reflects the successful marketing of OpenStack. OpenNebula mainly invests its resources in developing technology and serving its users, being really vendor agnostic and free of marketing.

There is also a quarterly comparative analysis of the community activity (mailing lists traffic mostly) of the four main open-source cloud management platforms: OpenStack, OpenNebula, Eucalyptus and CloudStack. The number of threads and participants in OpenStack is one order of magnitude higher than in OpenNebula. This mostly reflects a higher number of developers. Moreover, it is also worth noting that development coordination in OpenNebula is done through a redmine portal and not through a mailing list.

Resources Invested

We conservatively estimate the investment in OpenStack is approximately $300 million per year:

  • OpenStack Havana involved 950 developers almost completely hired by vendors. This is approximately $150 Million per year
  • OpenStack Foundation budget is approximately $10 Million per year
  • Marketing costs, i.e. marketing staff and external marketing programs, can be estimated in tens of millions per year
  • Just seven of the many start-ups involved in OpenStack have raised $120 million from VC. Assuming this is for 3 years. This is approximately $40 million per year
  • There are other direct costs from other many companies, there are almost 1,000 companies involved, that are also allocating resources to development, training, documentation,…, a big overhead in indirect costs, and of course opportunity costs

So $300 million per year is a good conservative estimate. We have seen other estimations above $0.5 billion per year, some reaching to $1 billion per year. In any case, over a few years, it’s billions. Will these companies ever get their money back?. I see VC’s starting to ask “Where’s our future money?”. Summarizing, a relatively small user base, and so penetration in the market, compared with the investment made by vendors and VCs. OpenNebula, with a budget at least two orders of magnitude lower, is achieving a similar user base. You can draw your own conclusions.

A New Cloud Provisioning Model: vDCs as a Service

Three years ago, driven by the needs of some of our larger users, we incorporated support for Virtual Data Centers (vDCs) and multiple Zones into OpenNebula 3.0. Since that time, this innovative vDC functionality has helped many IT organizations to make the transition towards the next generation of cloud infrastructures supporting on-demand provisioning of multiple fully-isolated vDCs. Thanks to the feedback received by many of these organizations during the last years, we have improved this functionality and its integration with the rest of subsystems. This post describes the new cloud provisioning model based on vDCs that is brought by OpenNebula 4.6. The new model offers an integrated and comprehensive framework for resource allocation and isolation in federated data centers and hybrid cloud deployments.

The Infrastructure Perspective

Common large IT shops have multiple Data Centers (DCs), each one of them consisting of several physical Clusters of infrastructure resources (hosts, networks and storage). These Clusters could present different architectures and software/hardware execution environments to fulfill the needs of different workload profiles. Moreover, many organizations have access to external public clouds to build hybrid cloud scenarios where the private capacity of the Data Centers is supplemented with resources from external clouds to address peaks of demand. Sysadmins need a single comprehensive framework to dynamically allocate all these available resources to the multiple groups of users.

For example, you could have two Data Centers in different geographic locations, Europe and USA West Coast, and an agreement for cloudbursting with two cloud providers, Amazon and SoftLayer. Each Data Center runs its own full OpenNebula deployment.

Resources
The Organizational Perspective

Users are organized in Groups (also called Projects, Domains, Tenants…). A Group is an authorization boundary that can be seen as a business unit if you are considering it as private cloud or as a complete new company if it is public cloud. A powerful, configurable ACL system is needed to enable different authorization scenarios, from the definition of group Admins to the privileges of the users that can deploy virtual machines. Each Group can execute different types of workload profiles with different performance and security requirements.

For example, you can think Web Development, Human Resources, and Big Data Analysis as business units represented by Groups in OpenNebula.

Groups

The following are common enterprise use cases in large cloud computing deployments:

  • On-premise Private Clouds Serving Multiple Projects, Departments, Units or Organizations. On-premise private clouds in large organizations require powerful and flexible mechanisms to manage the access privileges to the virtual and physical infrastructure and to dynamically allocate the available resources. In these scenarios, the Cloud Administrator would define a Group for each Department, dynamically allocating resources according to their needs, and delegating the internal administration of the Group to the Department IT Administrator.
  • Cloud Providers Offering Virtual Private Cloud Computing. Cloud providers providing customers with a fully-configurable and isolated environment where they have full control and capacity to administer its users and resources. This combines a public cloud with the control usually seen in a personal private cloud system.

A New Cloud Provisioning Model Based on vDCs

A Group is simply a boundary, you need to populate resources into the Group which can be consumed by the users of the Group. These resources are obtained from Resource Providers that can be located in different Data Centers, ending up with the creation of a vDC. A Resource Provider is a Cluster of infrastructure resources (physical hosts, networks, datastores and external clouds).

For example, you could create three different vDCs:

  • BLUE: Allocation of (ClusterA@DC_West_Coast + Cloudbursting) to Web Development
  • RED: Allocation of (ClusterB@DC_West_Coast + ClusterA@DC_Europe + Cloudbursting) to Human Resources
  • GREEN: Allocation of (ClusterC@DC_West_Coast + ClusterB@DC_Europe) to Big Data Analysis

vdcs
A vDC is a fully-isolated virtual infrastructure environment where a Group of users, under the control of the vDC admin, can create and manage compute, storage and networking capacity. The users in the vDC, including the vDC administrator, would only see the virtual resources and not the underlying physical infrastructure. The physical resources allocated by the cloud administrator to the vDC can be completely dedicated to the vDC, providing isolation at the physical level too.

The privileges of the vDC users and the administrator regarding the operations over the virtual resources created by other users can be configured. In a typical scenario the vDC administrator can create virtual networks, upload and create images and templates, and monitor other users virtual resources, while the users can only instantiate virtual machines and virtual networks to create their services. The administrators of the vDC have full control over resources and can also create new users in the vDC.

UsersVDCs
Users can then access their vDC through any of the existing OpenNebula interfaces, such as the CLI, Sunstone, OCA, or the OCCI and AWS APIs. vDC administrators can manage their vDCs through the CLI or the vDC admin view in Sunstone. Cloud Administrators can manage the vDCs through the CLI or Sunstone.

The Cloud provisioning model based on vDCs enables an integrated, comprehensive framework to dynamically provision the infrastructure resources in large multi-datacenter environments to different customers, business units or groups. This brings several benefits:

  • Partitioning of cloud physical resources between Groups of users
  • Complete isolation of users, organizations or workloads
  • Allocation of Clusters with different levels of security, performance or high availability
  • Containers for the execution of software-defined data centers
  • Way of hiding physical resources from Group members
  • Simple federation, scalability and cloudbursting of private cloud infrastructures beyond a single cloud instance and data center

Want to Try?

The Beta release of OpenNebula 4.6 will be available in few days. In the meantime you can enjoy this screencast about partitioning clouds with vDCs.

We are looking forward to your feedback!.