Openstack, Cloudstack and Swift

OpenStack

• OpenStack mainly consist of 3 core software projects which are :

1. OpenStack Compute Infrastructure (Nova), 
2. OpenStack Object Storage Infrastructure (Swift) and 
3. OpenStack Image Service Infrastructure (Glance)

CloudStack

• CloudStack is an Open source software designed for centralized management and massive scalability; 
• It enables the effective management of numerous geographically distributed servers from a single portal only and follow monolithic architecture. 
• OpenNebula follows classical cluster -like architecture with a front end and a set of cluster nodes to run the virtual machines (VMs).

Swift

• Object Storage (Swift): OpenStack Object Storage (Swift) is a scalable redundant storage system for objects and files. 
• Objects as well as files are written to multiple disk drives spread throughout servers in the data center, OpenStack software only responsible for ensuring data replication and integrity across the cluster. 
• OpenStack Object Storage (Swift): In Icehouse include a new feature which is discoverability, which dramatically improves workflows as well as saves time by allowing users to ask any Object Storage cloud what capabilities are available via API call.
• Client Connectivity : Swift is implemented in python. if your application is in none of theseprogramming languages, e.g. if it is in C++, they have some kind of client driver support.
• API: Swift has only object store API
• Swift implements a number of concepts (e.g. ring, proxy, account, container, object manager, updaters, auditors etc.) 
• Scalability: Swift requires special handling for large objects.
• Latency: it is typically observed with swift that the throughput increases with larger block size. It means that the latency is pretty high until we reach a reasonably large object size.
• You get usage metrics, VM, Host Metrics just out of the box where as Openstack requires your to setup different sub-services to get you going.
• If the need is beyond IaaS, ie., Big-Data, Container Orchestration, PaaS and etc., then Openstack provides you the umberlla to access all services seamlessly.
• Openstack is the best for managing private and public cloud. 
• Scripts are developled by openstack using which you can launch private cloud within minutes.
• OpenStack is compatible with KVM, Xen, LXC, QEMU, UML, Hyper-V etc. hypervisor. CloudStack software supports multiple hypervisors, such as Citrix XenServer, Oracle VM, VMware, KVM and vSphere. OpenNebula, support Xen, VMWare and KVM hypervisor. 
• Hypervisor is a software abstraction of a physical hardware platform that manages multiple guest operating system (OS) to run concurrently on an only single physical machine. Eucalyptus is manageable with Xen and KVM hypervisor