Abstract:
A hybrid cloud computing system having a private data center and a public cloud computing system is discussed. The private data center is managed by a first organization. The public cloud computing system is managed by a second organization, and the first organization is a tenant in the public cloud computing system. The hybrid cloud computing system is configured to generate a mapping that contextualizes virtual objects migrated between the private data center and the public cloud computing system based on the objects&#39; location. Such a mapping is maintained to expose the true hybridity of the hybrid cloud rather than present two distinct views of a private data center (or private cloud) and a public cloud.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/063,273, filed Oct. 13, 2014, the entire contents of which are incorporated by reference herein. 
    
    
     BACKGROUND 
     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. 
     SUMMARY 
     A method for managing a hybrid cloud computing system is provided. The method includes instantiating a first virtual object in a private data center managed by a first organization. The first virtual object is assigned a first identifier unique within the private data center. The method further includes instantiating a second virtual object in a public cloud computing system. The second virtual object is assigned a second identifier unique within the public cloud computing system. The first organization is a tenant in the public cloud computing system managed by a second organization. The method includes generating a mapping associated with the first virtual object, wherein the mapping comprises the first identifier having a context of the private data center and the second identifier having a context of the public cloud computing system. 
     Another method for managing a hybrid cloud computing system having a private data center and a public cloud computing system is provided. The private data center is managed by a first organization, and the first organization being a tenant in the public cloud computing system managed by a second organization. The method includes receiving a request to deploy a first virtual object in the public cloud computing system. The request comprises an indication that the first virtual object is associated with a second virtual object instantiated in the private data center. The method further includes instantiating the first virtual object in the public cloud computing system, assigning a first object identifier to the first virtual object, wherein the first object identifier is unique within the public cloud computing system, and updating, at the public cloud computing system. The mapping associates the first object identifier with the second virtual object and the first organization. 
     Further embodiments provide a non-transitory computer-readable medium that includes instructions that, when executed, enable one or more computer hosts to implement one or more aspects of the above method, and a cloud-based computing system that includes one or more computer hosts programmed to implement one or more aspects of the above method. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram that illustrates a computer system in which one or more embodiments may be utilized. 
         FIGS. 2A and 2B  are block diagrams depicting cross-cloud deployment operations of a hybrid cloud computing system, according to one embodiment of the present disclosure. 
         FIG. 3  is a flow diagram depicting a method for managing a hybrid cloud computing system, according to one embodiment of the present disclosure. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of a hybrid cloud computing system  100  in which one or more embodiments of the present disclosure may be utilized. Hybrid cloud computing system  100  includes a virtualized computing system  102  and a cloud computing system  150 , and is configured to provide a common platform for managing and executing virtual workloads seamlessly between virtualized computing system  102  and cloud computing system  150 . In one embodiment, virtualized computing system  102  may be a data center controlled and administrated by a particular enterprise or business organization, while cloud computing system  150  is operated by a cloud computing service provider and exposed as a service available to account holders, such as the particular enterprise in addition to other enterprises. As such, virtualized computing system  102  may sometimes be referred to as an on-premise data center(s), and cloud computing system  150  may be referred to as a “public” cloud service. In some embodiments, virtualized computing system  102  itself may be configured as a private cloud service provided by the enterprise. 
     As used herein, an internal cloud or “private” cloud is a cloud in which a tenant and a cloud service provider are part of the same organization, while an external or “public” cloud is a cloud that is provided by an organization that is separate from a tenant that accesses the external cloud. For example, the tenant may be part of an enterprise, and the external cloud may be part of a cloud service provider that is separate from the enterprise of the tenant and that provides cloud services to different enterprises and/or individuals. In embodiments disclosed herein, a hybrid cloud is a cloud architecture in which a tenant is provided with seamless access to both private cloud resources and public cloud resources. 
     Virtualized computing system  102  includes one or more host computer systems  104 . Hosts  104  may be constructed on a server grade hardware platform  106 , such as an x86 architecture platform, a desktop, and a laptop. As shown, hardware platform  106  of each host  104  may include conventional components of a computing device, such as one or more processors (CPUs)  108 , system memory  110 , a network interface  112 , storage  114 , and other I/O devices such as, for example, a mouse and keyboard (not shown). Processor  108  is configured to execute instructions, for example, executable instructions that perform one or more operations described herein and may be stored in memory  110  and in local storage. Memory  110  is a device allowing information, such as executable instructions, cryptographic keys, virtual disks, configurations, and other data, to be stored and retrieved. Memory  110  may include, for example, one or more random access memory (RAM) modules. Network interface  112  enables host  104  to communicate with another device via a communication medium, such as a network  122  within virtualized computing system  102 . Network interface  112  may be one or more network adapters, also referred to as a Network Interface Card (NIC). Storage  114  represents local storage devices (e.g., one or more hard disks, flash memory modules, solid state disks, and optical disks) and/or a storage interface that enables host  104  to communicate with one or more network data storage systems. Examples of a storage interface are a host bus adapter (HBA) that couples host  104  to one or more storage arrays, such as a storage area network (SAN) or a network-attached storage (NAS), as well as other network data storage systems. 
     Each host  104  is configured to provide a virtualization layer that abstracts processor, memory, storage, and networking resources of hardware platform  106  into multiple virtual machines  120   1  to  120   N  (collectively referred to as VMs  120 ) that run concurrently on the same hosts. VMs  120  run on top of a software interface layer, referred to herein as a hypervisor  116 , that enables sharing of the hardware resources of host  104  by VMs  120 . One example of hypervisor  116  that may be used in an embodiment described herein is a VMware ESXi hypervisor provided as part of the VMware vSphere solution made commercially available from VMware, Inc. Hypervisor  116  may run on top of the operating system of host  104  or directly on hardware components of host  104 . 
     Virtualized computing system  102  includes a virtualization management module (depicted in  FIG. 1  as virtualization manager  130 ) that may communicate to the plurality of hosts  104  via a network, sometimes referred to as a management network  126 . In one embodiment, virtualization manager  130  is a computer program that resides and executes in a central server, which may reside in virtualized computing system  102 , or alternatively, running as a VM in one of hosts  104 . One example of a virtualization management module is the vCenter® Server product made available from VMware, Inc. Virtualization manager  130  is configured to carry out administrative tasks for computing system  102 , including managing hosts  104 , managing VMs  120  running within each host  104 , provisioning VMs, migrating VMs from one host to another host, and load balancing between hosts  104 . 
     In one embodiment, virtualization manager  130  includes a hybrid cloud management module (depicted as hybrid cloud manager  132 ) configured to manage and integrate virtual computing resources provided by cloud computing system  150  with virtual computing resources of computing system  102  to form a unified “hybrid” computing platform. Hybrid cloud manager  132  is configured to deploy VMs in cloud computing system  150 , transfer VMs from virtualized computing system  102  to cloud computing system  150 , and perform other “cross-cloud” administrative task, as described in greater detail later. In one implementation, hybrid cloud manager  132  is a module or plug-in complement to virtualization manager  130 , although other implementations may be used, such as a separate computer program executing in a central server or running in a VM in one of hosts  104 . 
     In one embodiment, hybrid cloud manager  132  is configured to control network traffic into network  122  via a gateway component (depicted as a gateway  124 ). Gateway  124  (e.g., executing as a virtual appliance) is configured to provide VMs  120  and other components in virtualized computing system  102  with connectivity to an external network  140  (e.g., Internet). Gateway  124  may manage external public IP addresses for VMs  120  and route traffic incoming to and outgoing from virtualized computing system  102  and provide networking services, such as firewalls, network address translation (NAT), dynamic host configuration protocol (DHCP), load balancing, and virtual private network (VPN) connectivity over a network  140 . 
     In one or more embodiments, cloud computing system  150  is configured to dynamically provide an enterprise (or users of an enterprise) with one or more virtual data centers  180  in which a user may provision VMs  120 , deploy multi-tier applications on VMs  120 , and/or execute workloads. Cloud computing system  150  includes an infrastructure platform  154  upon which a cloud computing environment  170  may be executed. In the particular embodiment of  FIG. 1 , infrastructure platform  154  includes hardware resources  160  having computing resources (e.g., hosts  162   1  to  162   M ), storage resources (e.g., one or more storage array systems, such as SAN  164 ), and networking resources, which are configured in a manner to provide a virtualization environment  156  that supports the execution of a plurality of virtual machines  172  across hosts  162 . It is recognized that hardware resources  160  of cloud computing system  150  may in fact be distributed across multiple data centers in different locations. 
     Each cloud computing environment  170  is associated with a particular tenant of cloud computing system  150 , such as the enterprise providing virtualized computing system  102 . In one embodiment, cloud computing environment  170  may be configured as a dedicated cloud service for a single tenant comprised of dedicated hardware resources  160  (i.e., physically isolated from hardware resources used by other users of cloud computing system  150 ). In other embodiments, cloud computing environment  170  may be configured as part of a multi-tenant cloud service with logically isolated virtual computing resources on a shared physical infrastructure. As shown in  FIG. 1 , cloud computing system  150  may support multiple cloud computing environments  170 , available to multiple enterprises in single-tenant and multi-tenant configurations. 
     In one embodiment, virtualization environment  156  includes an orchestration component  158  (e.g., implemented as a process running in a VM) that provides infrastructure resources to cloud computing environment  170  responsive to provisioning requests. For example, if enterprise required a specified number of virtual machines to deploy a web applications or to modify (e.g., scale) a currently running web application to support peak demands, orchestration component  158  can initiate and manage the instantiation of virtual machines (e.g., VMs  172 ) on hosts  162  to support such requests. In one embodiment, orchestration component  158  instantiates virtual machines according to a requested template that defines one or more virtual machines having specified virtual computing resources (e.g., compute, networking, storage resources). Further, orchestration component  158  monitors the infrastructure resource consumption levels and requirements of cloud computing environment  170  and provides additional infrastructure resources to cloud computing environment  170  as needed or desired. In one example, similar to virtualized computing system  102 , virtualization environment  156  may be implemented by running on hosts  162  VMware ESX™-based hypervisor technologies provided by VMware, Inc. of Palo Alto, Calif. (although it should be recognized that any other virtualization technologies, including Xen® and Microsoft Hyper-V virtualization technologies may be utilized consistent with the teachings herein). 
     In one embodiment, cloud computing system  150  may include a cloud director  152  (e.g., run in one or more virtual machines) that manages allocation of virtual computing resources to an enterprise for deploying applications. Cloud director  152  may be accessible to users via a REST (Representational State Transfer) API (Application Programming Interface) or any other client-server communication protocol. Cloud director  152  may authenticate connection attempts from the enterprise using credentials issued by the cloud computing provider. Cloud director  152  maintains and publishes a catalog  166  of available virtual machine templates and packaged virtual machine applications that represent virtual machines that may be provisioned in cloud computing environment  170 . A virtual machine template is a virtual machine image that is loaded with a pre-installed guest operating system, applications, and data, and is typically used to repeatedly create a VM having the pre-defined configuration. A packaged virtual machine application is a logical container of pre-configured virtual machines having software components and parameters that define operational details of the packaged application. An example of a packaged VM application is vApp™ technology made available by VMware, Inc., of Palo Alto, Calif., although other technologies may be utilized. Cloud director  152  receives provisioning requests submitted (e.g., via REST API calls) and may propagates such requests to orchestration component  158  to instantiate the requested virtual machines (e.g., VMs  172 ). 
     In the embodiment of  FIG. 1 , cloud computing environment  170  supports the creation of a virtual data center  180  having a plurality of virtual machines  172  instantiated to, for example, host deployed multi-tier applications. A virtual data center  180  is a logical construct that provides compute, network, and storage resources to an organization. Virtual data centers  180  provide an environment where VM  172  can be created, stored, and operated, enabling complete abstraction between the consumption of infrastructure service and underlying resources. VMs  172  may be configured similarly to VMs  120 , as abstractions of processor, memory, storage, and networking resources of hardware resources  160 . 
     Virtual data center  180  includes one or more virtual networks  182  used to communicate between VMs  172  and managed by at least one networking gateway component (e.g., gateway  184 ), as well as one or more isolated internal networks  186  not connected to gateway  184 . Gateway  184  (e.g., executing as a virtual appliance) is configured to provide VMs  172  and other components in cloud computing environment  170  with connectivity to external network  140  (e.g., Internet). Gateway  184  manages external public IP addresses for virtual data center  180  and one or more private internal networks interconnecting VMs  172 . Gateway  184  is configured to route traffic incoming to and outgoing from virtual data center  180  and provide networking services, such as firewalls, network address translation (NAT), dynamic host configuration protocol (DHCP), and load balancing. Gateway  184  may be configured to provide virtual private network (VPN) connectivity over a network  140  with another VPN endpoint, such as a gateway  124  within virtualized computing system  102 . In other embodiments, gateway  184  may be configured to connect to communicate with virtualized computing system  102  using a high-throughput, dedicated link (depicted as a direct connect  142 ) between virtualized computing system  102  and cloud computing system  150 . In one or more embodiments, gateways  124  and  184  are configured to provide a “stretched” layer-2 (L2) network that spans virtualized computing system  102  and virtual data center  180 , as shown in  FIG. 1 . 
     While  FIG. 1  depicts a single connection between on-premise gateway  124  and cloud-side gateway  184  for illustration purposes, it should be recognized that multiple connections between multiple on-premise gateways  124  and cloud-side gateways  184  may be used. Furthermore, while  FIG. 1  depicts a single instance of a gateway  184 , it is recognized that gateway  184  may represent multiple gateway components within cloud computing system  150 . In some embodiments, a separate gateway  184  may be deployed for each virtual data center, or alternatively, for each tenant. In some embodiments, a gateway instance may be deployed that manages traffic with a specific tenant, while a separate gateway instance manages public-facing traffic to the Internet. In yet other embodiments, one or more gateway instances that are shared among all the tenants of cloud computing system  150  may be used to manage all public-facing traffic incoming and outgoing from cloud computing system  150 . 
     In one embodiment, each virtual data center  180  includes a “hybridity” director module (depicted as hybridity director  174 ) configured to communicate with the corresponding hybrid cloud manager  132  in virtualized computing system  102  to enable a common virtualized computing platform between virtualized computing system  102  and cloud computing system  150 . Hybridity director  174  (e.g., executing as a virtual appliance) may communicate with hybrid cloud manager  132  using Internet-based traffic via a VPN tunnel established between gateways  124  and  184 , or alternatively, using direct connect  142 . In one embodiment, hybridity director  174  may control gateway  184  to control network traffic into virtual data center  180 . In some embodiments, hybridity director  174  may control VMs  172  and hosts  162  of cloud computing system  150  via infrastructure platform  154 . 
       FIGS. 2A and 2B  are block diagrams depicting cross-cloud deployment operations of a hybrid cloud computing system  200 , according to one embodiment of the present disclosure. Hybrid cloud computing system  200  is configured to provide a common platform for executing virtual workloads seamlessly between a private data center  202 , which may configured similar to virtualized computing system  102 , and a public cloud computing system  250 , which may be configured similar to cloud computing system  150  in  FIG. 1 . Private data center  202  may be managed by an enterprise (first organization), and the enterprise may be a tenant in public cloud computing system  250 , which is managed by a cloud provider (second organization). For example, a virtual data center  220  within public cloud computing system  250  may be allocated to the enterprise as one tenant, while other virtual data centers  222  having other VMs  224  associated other tenants may be allocated in public cloud computing system  250 . 
     In the embodiment shown in  FIG. 2A , an instance  206  of a packaged virtual machine application has been deployed and instantiated in private data center  202 . Application instance  206  is comprised of a plurality of VMs  208 ,  210 , and  212  interconnected by a virtual network  214 . For sake of illustration purposes, the application instance  206  is a multi-tier application having a web tier implemented by VM  208  executing as a web server, an application tier implemented by VM  210  executing as an application server, and a database tier implemented by VM  212  executing as a database server. It should be recognized that other types of applications and virtual machine application packages may be used. 
     As part of the deployment of application instance  206 , virtualization manager  130  assigns an object identifier to each of the “virtual objects” created, including an object identifier that refers to application instance  206  as a whole, but also individual object identifiers to each of VMs  208 ,  210 ,  212 , and virtual network  214 . Each assigned identifier may be unique within private data center  202 . In other words, the identifier may be unique within a management domain comprised of the hosts and virtual computing resources overseen by virtualization manager  130 . In the example shown in  FIG. 2A , application instance  206  is assigned an object identifier “ab-12-cd”, VMs  208 ,  210 ,  212  are assigned the object identifiers “aa-11-bb”, “bb-22-cc”, “cc-33-dd”, respectively, and virtual network  214  is assigned the object identifier “88-aa-88.” In some implementations, identifiers assigned to virtual objects may have a format made of an object type and an auto-incremented numeral. For example, the identifier for a VM may be “vm-092,” where “vm” is the virtual machine object type and “092” is the counter. In other implementations, an identifier assigned to a virtual object may be a multi-bit value (e.g., 128-bit integer) derived from other metadata related to the virtual object, such as BIOS information from the physical host on which a VM is executing, or by hashing the path to a virtual machine configuration file. Similarly, cloud computing system  250  assigns object identifiers to virtual objects for tracking the virtual objects created and owned within the management domain overseen by infrastructure platform  154 . 
     In one or more embodiments, private data center  202  may have its own identifier. That is, the management domain defined by private data center  202  may be assigned a unique identifier (e.g., “datacenter-001”). Private data center  202  may be associated with a tenant identifier (e.g., “tenant-001”) specifying the organization managing the private data center, i.e., the enterprise. 
     During operation, hybrid cloud manager  132  (e.g., in response to user input) may deploy a portion, or all, of application instance  206  to virtual data center  220 . In some embodiments, hybrid cloud manager  132  may transfer one or more existing virtual computing resources (e.g., VM  208 ) from private data center  202  to virtual data center  220  (the operation being depicted by arrow  230  in  FIG. 2A ). In other embodiments, hybrid cloud manager  132  may simply deploy additional virtual computing resources, such as VMs, virtual networks, and virtual storage, in virtual data center  220  for use by application instance  206 . In some cases, this cross-cloud deployment may be performed to handle a surge in workload that requires additional virtual computing resources, or alternatively, may be performed as part of the initial deployment of application instance. In one scenario depicted in  FIG. 2B , the web tier of a multi-tier application may be scaled out within virtual data center  220  in response to increased user traffic to the multi-tier application. As such, hybridity director  174  instantiates within virtual data center  220  a plurality of VMs  208 ,  252 ,  254 , and  256 , which are part of application instance  206 , and a virtual network  258 , which is a component of a stretched network combining with virtual network  214 . As shown in  FIG. 2B , VMs  208 ,  252 ,  254 ,  256  and virtual network  258  are assigned the object identifiers “aa-11-bc,” “aa-11-bd,” “aa-11-be,” “aa-11-bf,” and “dd-00-dd”, respectively. 
     However, cloud computing system  250  typically assigns object identifiers to the instantiated virtual objects without any correlation to object identifiers assigned by private data center  202 . That is, the object identifiers assigned to virtual objects within cloud computing system  250  are designed to be unique only within the management domain overseen by infrastructure platform  154 . The same object identifiers assigned to a VM might not be usable when that VM is migrated from private data center  202  to cloud computing system  250 , as the object identifier might have already been assigned to another virtual object within cloud computing system  250 , including virtual objects allocated to other tenants. For example, as shown in  FIG. 2B , the object identifier “aa-11-bb” associated with VM  208  on the private data center side has already been assigned to a VM  224  allocated to another tenant within cloud computing system  250 , resulting in duplicate and conflicting identifiers. Instead, the migrated VM  208  is assigned a different object identifier “aa-11-bc.” Furthermore, applications, virtual machines, or policies in private data center  202  may refer to specific object identifiers (assigned by private data center  202 ), but would otherwise be linked to an unrelated set of virtual objects if applied to cloud computing system  250 . For example, an object identifier “1” on a tenant instance “A” may be represented by an identifier “app-54” as its local identifier connected with an e-mail server application policy, such as an Microsoft® Exchange® policy. 
     Accordingly, embodiments of the present disclosure provide a mechanism to re-contextualize a specific set of object identifiers from a private data center to the corresponding virtual data center in a public cloud computing system. In this way, an object identifier referring to a particular application instance may still refer to that application instance when being migrated from a private data center to the public cloud, and vice versa, from the public cloud back to the private data center. 
     In one or more embodiments, hybrid cloud manager  132  is configured to generate a mapping  240  associating virtual objects with a local object identifier contextualized by the virtual object&#39;s location. Similarly, hybridity director  174  on the cloud side may be configured to maintain a corresponding mapping  242 . Hybrid cloud manager  132  may generate a mapping for virtual objects within private data center  202  that tracks the tenant and the particular data center, while the mapping for virtual objects within cloud computing system  250  may be tracked by a contextualization of the tenant and the object identifier (e.g., packaged application identifier) in public cloud computing system  250 . 
     It is noted that the mapping for virtual objects may be created and maintained at private data center (e.g., by hybrid cloud manager  132 ), at public cloud computing system  250  (e.g., by hybridity director  174 ), or both. In one scheme, object identifiers for virtual objects and an audit trail is maintained on both cloud endpoints (i.e., both public cloud computing system  250  and private datacenter  202 ). Hybrid cloud manager may maintain the audit trail (e.g., by building a linked list in one implementation) that tracks the history of a specific virtual object with each cloud endpoint tracking itself and immediate predecessor. This allows embodiments to treat the context as a chain of cloud-id to cloud-id mappings along a lifecycle of a virtual object: i.e., create-migrate-migrate- . . . -migrate-delete. As such, each system within hybrid cloud preserves historic data of all the mappings of all virtual objects to allow this reconstruction. This may be also useful to track the historical location of a virtual object for auditing and compliance purposes. 
     In another scheme, embodiments of the present disclosure may contextualize the object identifiers associated with each virtual object and an audit trail as metadata that follows a virtual object. This enables application-specific data that should be kept in an up-to-date fashion alongside a specific virtual object. In some embodiments, a linked list of historical context where all items in the list are maintained alongside the virtual object via metadata managed by either hybrid cloud manager  132 , hybridity director  174 , or both. 
     In one embodiment, hybrid cloud manager  132  updates mapping  240  to track that a virtual object in the public cloud is a virtual computing resource (e.g., VM) corresponding to a virtual object that had been migrated from (i.e., prior deployed in) private data center  202 . Using the example shown in  FIG. 2B , mapping  240  may indicate that VM  208  having the object identifier “aa-11-bc” in the context of cloud computing system  250  is associated with the corresponding VM  208  which had the object identifier “aa-11-bb” in the context of private data center  202 . 
     In another embodiment, hybrid cloud manager  132  updates mapping  240  to holistically track virtual objects or entities that have a presence on both private data center  202  and in public cloud computing system  250 . Hybrid cloud manager  132  maps such virtual objects to their component parts, i.e., a set of virtual objects in the private data center and another set in the public cloud. In one example, mapping  240  is updated to track an application (application instance  206 ) as having a database tier (VM  210 ) and application tier (VM  212 ) within private data center  202 , and having a scaled-out web tier (VMs  208 ,  252 ,  254 ,  256 ) within public cloud computing system  250 . In another example, mapping  240  is updated to track a network  260  that stretches a first virtual network  214  within private data center  202  to a second virtual network  258  within public cloud computing system  250 . 
     In one or more embodiments, hybrid cloud manager  132  and hybridity director  174  are configured to exchange messaging that coordinates a consistent mapping within the hybrid cloud computing system. In some embodiments, hybrid cloud manager  132  and hybridity director  174  may use a heartbeat mechanism to track the continued existence of related virtual objects as workloads evolve on both the cloud side and the private data center side for a given application, network, and/or workload. The heartbeat mechanism enables tracking of stretched virtual objects that span both private data center and public cloud computing system  250 . For example, a policy object that is present on both sides should have the same identifier and maintained consistently from an identity perspective. A packaged application that stretches across the hybrid cloud computing system should be maintained in a similar manner. 
       FIG. 3  is a flow diagram depicting a method  300  for managing a hybrid cloud computing system, according to one embodiment of the present disclosure. While method  300  is described in conjunction with components of the system shown in  FIGS. 1, 2A, and 2B , other components in computer systems  100  and  200  may perform the steps of method  300 , as well as other systems may perform the described method. 
     Method  300  begins at step  302 , hybrid cloud manager  132  instantiates a first virtual object in private data center  202  managed by a first organization (i.e., an enterprise). In one embodiment, hybrid cloud manager  132  assigns a first identifier to the first virtual object, the first identifier being unique within private data center  202 . 
     At step  304 , hybrid cloud manager  132  transmits a request to deploy a second component of the virtual object in public cloud computing system  250 . Hybrid cloud manager  132  may request the second component of the virtual object be deployed in a virtual data center allocated to the first organization as a tenant within public cloud computing system  250 . 
     In one case, the deployment request may include an indication that the second virtual object is a migrated virtual machine corresponding to the first virtual object (as specified by the first object identifier). In other cases, the deployment request may include an indication that the first virtual object and the second virtual object are component parts of a (third) virtual object spanning the public cloud computing system and the private data center. For example, the third virtual object may be a packaged virtual machine application (e.g., application instance  206 ) having a first plurality of VMs (e.g., VMs  210 ,  212 ) deployed in private data center  202  and a second plurality of VMs (e.g., VMs  208 ,  252 ,  254 ,  256 ) to be deployed in a virtual data center in public cloud computing system  250 . In another example, the third virtual object may be a virtual network comprised of a first virtual network (e.g., network  214 ) stretching from private data center  202  to a second virtual network (e.g., network  258 ) in public cloud computing system  250 . 
     A deployment request for a virtual machine being migrated (e.g., VM  208 ) may include a set of files, which can include configuration file(s), virtual disk file(s), virtual disk delta file(s) and configuration file(s) associated with VM snapshot(s), basic input output system (BIOS) file(s), log file(s), and the like, packaged for distribution according a format, such as the standardized Open Virtualization Format (OVF). In one implementation, metadata in the virtual machine may be modified to specify the first identifier associated with the first virtual object having a context of private data center  202 . As such, the deployment request may include metadata containing the first identifier associated with the first virtual object. 
     At step  306 , responsive to receiving a deployment request from hybrid cloud manager  132 , hybridity director  174  instantiates the second virtual object in public cloud computing system  250 . In one embodiment, hybridity director  174  assigns to the second virtual object a (second) identifier, which is unique within cloud computing system  250 . 
     At step  308 , hybridity director  174  updates a mapping  242  associating the second identifier (of the second virtual object) with a corresponding virtual object deployed in private data center  202  and with the first organization. 
     At step  310 , hybridity director  174  transmits a response to hybrid cloud manager  132  indicating the result of the deployment request. The response may indicate a status (e.g., success, error) of the deployment request. In some embodiments, the response may include the second identifier assigned by the public cloud computing system. In embodiments where the deployment request was a transfer of an existing VM, hybrid cloud manager  132  may de-instantiate the first virtual object in the private data center, responsive to a successful deployment of the second virtual object in the public cloud computing system. 
     At step  312 , hybrid cloud manager  132  generates a mapping  240  associated with the first virtual object. Mapping  240  may include the first identifier having a context of private data center  202  and the second identifier having a context of public cloud computing system  250 . In some implementations, the second identifier from public cloud computing system  250  may be received via the returned results in step  310 , or alternatively, provided by a heartbeat message periodically received from hybridity director  174 . In some embodiments, the mapping associates the first identifier within the context of the first organization and private data center  202 , and also associates the second identifier within the context of the first organization as a tenant in public cloud computing system  250 . 
     Although one or more embodiments have been described herein in some detail for clarity of understanding, it should be recognized that certain changes and modifications may be made without departing from the spirit of the disclosure. The various embodiments described herein may employ various computer-implemented operations involving data stored in computer systems. For example, these operations may require physical manipulation of physical quantities—usually, though not necessarily, these quantities may take the form of electrical or magnetic signals, where they or representations of them are capable of being stored, transferred, combined, compared, or otherwise manipulated. Further, such manipulations are often referred to in terms, such as producing, yielding, identifying, determining, or comparing. Any operations described herein that form part of one or more embodiments of the disclosure may be useful machine operations. In addition, one or more embodiments of the disclosure also relate to a device or an apparatus for performing these operations. The apparatus may be specially constructed for specific required purposes, or it may be a general purpose computer selectively activated or configured by a computer program stored in the computer. In particular, various general purpose machines may be used with computer programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform the required operations. 
     The various embodiments described herein may be practiced with other computer system configurations including hand-held devices, microprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers, and the like. 
     One or more embodiments of the present disclosure may be implemented as one or more computer programs or as one or more computer program modules embodied in one or more computer readable media. The term computer readable medium refers to any data storage device that can store data which can thereafter be input to a computer system—computer readable media may be based on any existing or subsequently developed technology for embodying computer programs in a manner that enables them to be read by a computer. Examples of a computer readable medium include a hard drive, network attached storage (NAS), read-only memory, random-access memory (e.g., a flash memory device), a CD (Compact Discs)—CD-ROM, a CD-R, or a CD-RW, a DVD (Digital Versatile Disc), a magnetic tape, and other optical and non-optical data storage devices. The computer readable medium can also be distributed over a network coupled computer system so that the computer readable code is stored and executed in a distributed fashion. 
     Although one or more embodiments of the present disclosure have been described in some detail for clarity of understanding, it will be apparent that certain changes and modifications may be made within the scope of the claims. Accordingly, the described embodiments are to be considered as illustrative and not restrictive, and the scope of the claims is not to be limited to details given herein, but may be modified within the scope and equivalents of the claims. In the claims, elements and/or steps do not imply any particular order of operation, unless explicitly stated in the claims. 
     Many variations, modifications, additions, and improvements are possible. Plural instances may be provided for components, operations or structures described herein as a single instance. Boundaries between various components, operations and data stores are somewhat arbitrary, and particular operations are illustrated in the context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within the scope of the disclosure(s). In general, structures and functionality presented as separate components in exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the appended claim(s).