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OpenStack Journal: Article

Overview of the OpenStack Cloud

Distilling terminology and acronyms that define OpenStack

Overview
OpenStack is an Infrastructure as a Service offering. (see my prior post for an explanation of IaaS).

OpenStack is an OpenSource project, founded by RackSpace, NASA and others.

OpenStack can be deployed as a public or private cloud.

The OpenStack projects are: CINDER, GLANCE, KEYSTONE, NOVA, QUANTUM, SWIFT.

OpenStack Compute: (NOVA)
Project NOVA, or OpenStack Compute, provisions and manages on-demand virtual machines and associated resources: CPU, Memory, Disk and Network.

Virtual machines can be started, stopped, suspended, created and deleted, while network options for a virtual machine are static, DHCP, or IPv6.

The virtual machines run on hypervisors such as XEN or KVM, but others are supported too - even VMware ESXi!

Users and administrators use the GUI to request virtual machines, while developers may typically use an API.

Security? Of course there are security groups, similar to AWS, to control access to virtual machines and RBAC to govern user access by role and project.

Storage
Object Storage (project SWIFT)

Object Storage is a distributed storage system for static data such as files (graphics, movies) and virtual machine images. Objects and files are written to multiple disk drives, while OpenStack is responsible for ensuring data replication and integrity. Storage scales horizontally by adding new servers.  If a server or hard drive fails, OpenStack replicates its content from other active servers to new servers in the cluster. Since OpenStack uses software to ensure data replication and distribution across servers, inexpensive servers can be used rather than expensive storage hardware.

Block storage (project CINDER)
Block storage is essentially volumes used by OpenStack virtual machines. Snapshots back up data stored on block storage volumes. Snapshots can be restored or used to create a new block storage volume.

Network (project QUANTUM)
OpenStack provides networking models to accomodate different applications or users. Standard network models include flat networks or VLANs to separate servers and network traffic. OpenStack Networking manages IP addresses, to allocate static  or DHCP addresses. Floating IP addresses allow traffic to be dynamically rerouted to any compute resource,  for example to redirect traffic during maintenance or in the case of a failure. OpenStack Networking has an extension framework to add intrusion detection systems (IDS), load balancing, firewalls and virtual private networks (VPN) .

Shared Services
Identity services (project KEYSTONE)
OpenStack Identity provides a central repository of users mapped to the OpenStack services they can access. OpenStack identity is a common authentication system and integrates with existing backend directory services such as LDAP. It supports several forms of authentication including username and password, tokens and AWS-type logins. The identity service also provides a queryable list of services deployed in the OpenStack cloud and users can programmatically determine their level of access.
OpenStack.

OpenStack Administrators can:

  • Configure centralized policies across users and systems
  • Create users and tenants and define permissions for compute, storage and networking resources using role-based access control (RBAC)
  • Integrate with an existing directory like LDAP, allowing for a single source of identity authentication across the cloud.

Image services (Project GLANCE)

The OpenStack Image Service provides discovery, registration and delivery services for disk and server images. Saved images can be used as a template to get new virtual servers up and running (especially useful for multiple servers of the same type and configuration). It can also be used to store and catalog an umlimited number of backups.

The image service stores private and public images in a variety of formats:

  • AMI
  • qcow2 (Qemu/KVM)
  • OVF (Open Virtualization Format)
  • RAW
  • VDI (VirtualBox)
  • VHD (Hyper-V)
  • VMDK (VMWare)

Image below courtesy of OpenStack.org

More Stories By Jonathan Gershater

Jonathan Gershater has lived and worked in Silicon Valley since 1996, primarily doing system and sales engineering specializing in: Web Applications, Identity and Security. At Red Hat, he provides Technical Marketing for Virtualization and Cloud. Prior to joining Red Hat, Jonathan worked at 3Com, Entrust (by acquisition) two startups, Sun Microsystems and Trend Micro.

(The views expressed in this blog are entirely mine and do not represent my employer - Jonathan).

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