Changes between Version 18 and Version 19 of orca-introduction

04/22/11 16:28:28 (8 years ago)
ibaldin (IP:



  • orca-introduction

    v18 v19  
    1616 * Substrate - a collection of resources under specific administrative ownership. Examples of substrate are servers (virtualizable or not), network links, data sets, measurement resources.  
    1717 * Sliver - a smallest unit of some resource that is independently programmable and/or indepen- dently controllable in some resource-specific fashion. Each sliver is granted from a single substrate provider. An example of a sliver can be a Virtual Machine created inside a cloud of a specific provider. 
    18  * Slices combine multiple slivers from multiple substrate providers into a coherent set usable by an experimenter or application. Usually slivers in a slice need to be connected to be usable, although this requirement can be relaxed under some circumstances. 
     18 * Slices are groupings of multiple slivers from multiple substrate providers. 
    1919 * Guest - a distributed software environment running within collection of slivers configured to order, possibly from different substrate providers. Some guests will be long-running services that require different amounts of resources at different stages of execution. The guests may range from virtual desktops to complex experiments to dynamic instantiations of distributed applications and network services. 
    3434Authorities delegate resources to brokers (one authority can delegate resources to several brokers). Brokers hold the promised resources until Service Managers request them. Brokers issue tickets for resources from different authorities to a Service Manager and a Service Manager redeems those tickets at Authorities. Authorities instantiate the resource slivers and pass the control of them to the Service Manager. Pluggable control and access policies help mediate these transactions. Query interfaces allow actors to asynchronously determine the state of other actors.  
     36Slices are used to group resources together. A slice in a Service Manager represents resources owned by a particular user (e.g. for the purpose of an experiment). A slice in a broker represents a portion of slivers given to a particular service manager slice from this broker. A slice in an authority represents the resources given by this authority to a particular service manager slice. Notice that architecturally in ORCA ''only the Service Manager knows the exact composition of the slice''. All other actors may have only a partial view of the slice.  
    3638== Further reading ==