Cloud architectures are used in cloud computing and cloud storage systems for offering infrastructure-as-a-service (IaaS) cloud services. Examples of cloud architectures include the VMware vCloud™ Director cloud architecture software, Amazon EC2™ web service, and OpenStack™ open source cloud computing service. IaaS cloud service is a type of cloud service that provides access to physical and/or virtual resources in a cloud environment. These services provide a tenant application programming interface (API) that supports operations for manipulating IaaS constructs such as virtual machines (VMs) and logical networks. However, the use of such public cloud services is typically kept separate from the use of existing computing resources in data centers managed by an enterprise.
Hybrid cloud infrastructures combine public cloud services with privately maintained computing infrastructures, where the combined infrastructure is accessible to end users according to a standard interface. That is, the end user need not know what resources are maintained or stored in the private infrastructure and what resources are maintained or stored in the public cloud.
Hybrid cloud infrastructures are used to deploy multi-tiered applications to end users. Multi-tiered applications often comprise a plurality of components (for example, VMs), each of which performs one or more discrete functions for the overall application. When application components are deployed to a hybrid cloud, some (or all) components communicate regularly and frequently with one another. Thus, it is advantageous to deploy these components on a single host, or on a single cluster or set of co-located hosts, whether that host is on the privately maintained infrastructure or in the public cloud. However, for a variety of reasons, a system administrator may deploy such components (which are referred to as being in heavy communication with one another) to different host systems in the hybrid cloud computing system. For example, communication patterns between components may not be predictable prior to deploying the components. Further, it may be the case that the components are deployed to different hosts (or to different cloud infrastructures) as a result of administrator error. Finally, some multi-tiered applications perform “auto-scaling” when the application is utilized beyond some threshold of activity. When an application is auto-scaled, virtual machines are automatically created to handle increased system load. However, typical auto-scaling solutions are usually unconcerned with keeping application components that frequently communicate with one another together on a common host. As a result, application components that frequently communicate with one another may be deployed to hosts that are remote from each other. Thus, the application components are required to communicate over a network link between hosts. Since network links introduce latency due to network utilization and distance between end points, and unreliability due to network outages, such a deployment of frequently communicating application components results in certain inefficiencies that would have been avoided had the components been deployed to the same host.