Virtualization and Cloud

Jonathan Gershater

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Top Stories by Jonathan Gershater

Eucalyptus is an open source Infrastructure as a Service cloud offering. What is unique about Eucalyptus is that it is compatible with Amazon AWS APIs. This means that you can: Use Eucalyptus commands to manage Amazon or Eucalyptus instances. Freely move instances between a Eucalyptus private cloud and the Amazon Public cloud to create a hybrid cloud. Eucalyptus leverages operating system virtualization, such as KVM or XEN, to achieve isolation between applications and stacks. Operating system virtualization dedicates CPU and RAM to systems and applications such that they don't interfere with each other. In cloud parlance, this is called isolation and is essential to achieve multi-tenancy. (For a refresher on basic cloud terminology, see here; for a refresher on Infrastructure as a Service, see here). Cloud computing layers on top of operating system virtualization... (more)

Cloud Computing Easily Understood - SaaS

In prior blog posts, I described Infrastructure as a Service (IaaS) and Platform as a Service (PaaS). To recap: If I use IaaS I get servers onto which I can load software and applications which I then maintain, though I don't need to maintain the hardware. I can customize the applications and software running on the servers, at will. If I use PaaS, I get a platform of ready to use web servers, application servers, databases etc. I write my own software application and host it at the PaaS provider. I maintain the software I write, but not the application servers, databases or ha... (more)

The Fundamental Flaw with LinkedIn Connections

Assumption A first-degree direct LinkedIn connection implies that the two parties know each well. Problem Using this assumption, two unconnected LinkedIn users attempt to connect via an intermediary. What often happens is that the first degree connections are in fact very weak connections, and thus of no use to the third party attempting to connect via the intermediary. Example I log into LinkedIn and would like an introduction to Brent. I view Brent's profile and notice that his first degree connection, Brian, is also a first degree connection with me. So I ask Brian for an int... (more)

Tutorial: Build a Private Cloud in Twenty Minutes

OpenStack is an open-source cloud framework for building on-demand Infrastructure as a Service. This tutorial in essence distills from this two-page set of instructions for setting up devstack on a single server primarily for use by developers. Hardware I used a DELL 1950 with 8 GB of RAM, internal hard-drives and two 1000 MB NICs. Download and Set Up Ubuntu Download Ubuntu 11.10 from here and burn to DVD Boot the server from the DVD and start the install. I installed the BASE SYSTEM and only one optional package, the OpenSSH Server. I named my server "ubuntu-server" I configured... (more)

Security in the Public Cloud Is a Shared Responsibility

When you host applications in the public cloud, you assume partial responsibility for securing the application. The cloud provider, for example Amazon Web Services (AWS), secures the physical data center (with locked badge entry doors, fences, guards etc) in addition to securing the physical network with perimeter firewalls. This is no significant change from how you secure your corporate datacenter. Just like you enhance the security of physical and virtual servers in your datacenter with host-based firewalls (ip tables, Windows firewall), anti-virus and intrusion detection, so... (more)