Cloud Layers

Cloud Layers

1. Imagine if the Cloud infrastructure is like a 3-D cylinder, which can be sliced horizontally (Horizontal Slices) and/or vertically (Vertical Slices)

   • A layer represents Cloud resources that share common characteristics.
     • The layering concept helps in understanding the relations and interactions amongst Cloud resources

2. Vertical Slices

   • The top view of the Cloud results in three layers which are known as a storage layer, a server layer, and a network layer.
     • –The storage layer consists of storage components, –the server layer consists of physical servers, and –the network layer consists of the network components.
     • The components of each layer are grouped and each group within a layer is known as sub-layers; that is we have network sub-layers, storage sub-layers and server sub-layers.
     • The properties of the members of each sub-layer are carefully selected such that a sub-layer can satisfy its planned properties.
       • A server sub-layer is then connected with a storage and a network sub-layers to form a unified group, which is called a collaborating sub-layer.
         • Collaborating sub-layers are associated with properties and policies. These are important for managing the infrastructure when hosting users applications

3. Horizontal Slices

   • –a physical layer, –a virtual layer, and –a application layer.
   • Physical Layer :The physical layer represents physical resources (server, storage or network devices) and their management software components.
     • The management software component could, for example, be an operating system, a hypervisor, or a firmware
       • The physical layer is associated with policies and properties.
         • The policies and properties govern the interactions of physical resources
   • The virtual layer consists of virtual resources which are hosted at physical resources.
     • a virtual machines (VM), a virtual disk or a virtual network
     • Cloud customers using IaaS have to fully maintain their VMs including guest operating systems
     • The virtual layer should be transparent to Cloud customers using SaaS service and PaaS services.
   • Application Layer
     • The application layer represents resources of software applications and software platforms (refer to as an application resource).
       • An application resource could be hosted either at virtual resources or directly at physical resources.
         • The earlier is the most commonly known case, i.e. hosting an application resource at the virtual layer.
   • Entities within a layer are organized into domains. A domain represents related resources which enforce the domain policy
   • The physical domains are related to a specific Cloud infrastructure and, therefore, are associated with the infrastructure properties and policies
   • The virtual and application domains are a Cloud user specific and therefore are associated with the Cloud user properties
   • Domains - interact amongst themselves within a layer. Collaborating domain - interaction amongst its members using a defined policy.
   • Domains and collaborating domains help in managing the distribution and coordination of the resources of the Cloud infrastructure in normal operations as well as during incidents such as hardware failures or a whole data-center failure
   • A federated cloud (also called cloud federation) is the deployment and management of multiple external and internal cloud computing services to match business needs. A federation is the union of several smaller parts that perform a common action.
     • Collaborations within the federated Cloud can be abstracted in forms of “Emergency Domains”
       • emergency domain consists of a set of physical collaborating domains where each collaborating domain is specific to a Cloud provider.