The opening speech was given by Scott Guthrie – Corporate Vice President at Microsoft in charge of the development platform for Windows Azure – who presented the features introduced in Windows Azure latest spring release. This post will summarize the main features shipped with the release.

A new administration portal

The administration portal has been rewritten in HTML5 to replace the previous Silverlight version. This is a welcome change that finally solves all the browser compatibility issues, and offers a clearer and more dynamic interface to the end-user. The portal exposes several stats which comes in handy when monitoring different resources such as CPU usage, available memory, disk throughput…

However the new portal is still in preview mode and not all the features are yet available, hence some back-and-forth navigation between the preview version and the old portal will be necessary until Microsoft finishes the migration. Amongst the missing features we can list the absence of the co-admin management and of the Service Bus, Access Control & Caching section.

The new portal can be reached through the URL

A true IaaS offering

Up until now, the Azure platform was focusing mainly on PaaS-type deployments, with an IaaS offering that was somehow quite limited. With the latest spring release, Windows Azure is closing the gap with its IaaS competitors by supporting the ability to run and deploy durable VMs in the cloud.

The fact that a VM is durable means that the content of its disk persists across reboots. One of Azure limitations was due to the fact that the VM role was completely stateless and any added content to a VM was lost after the instance was rebooted or deleted.

With the introduction of IaaS Virtual Machines, the content of the VM disk is persisted, which makes it possible to delete a VM instance and re-create it at a later date in the exact same state (by using the same logical OS disk) – this way avoiding getting overcharged if the VM is not used 24/7.

A VM instance can be created:

  • By creating and uploading a VHD disk – this was the only way to deploy a VM role previous to this release.
  • By selecting from a catalogue of existing OS images, which as of today include Windows Server 2008/2012, SQLServer 2012 and various Linux distributions: CentOS, Suse, Ubuntu.
  • By selecting from a custom image. The custom image would have previously been captured from an existing VM to be used as a template for rolling out new VMs.
The Azure platform now enables inter-VM communication through the deployment of VMs under the same cloud service(previously known as hosted service).

Windows Azure Virtual Network

Windows Azure now offers the possibility to create virtual networks (VPNs) between cloud resources, and to extend this connectivity to the on-premise infrastructure using the IPSEC protocol. This allows for hybrid cloud scenarios where services that need to be hosted on-premise (e.g. because they store sensitive information, such as databases) can be securely called by Azure resources.

Also new to this release is the ability to define a set of IP ranges for networks and sub-networks, and to choose whether to use an Azure or an on-premise DNS service for the name resolution of the cloud instances.

Distributed Caching

The Azure platform now offers a distributed in-memory caching solution to be used by Azure applications: Windows Azure Caching.

The cache can be distributed across existing web and worker roles and it uses part of their available memory in a co-located model. This approach comes for free as no additional cloud resources need to be deployed. The other option is to dedicate worker role instances which allows for a larger pool of caching memory – up to hundreds of GBs.

The cache can be dynamically resized and that operation does not require any code or application redeployment. The cache is built on top of the AppFabric solution , which is traditionally used on-premise,  with however some restrictions (for a detailed list of differences between the two versions, see

The cache can be accessed by any ASP.Net application hosted in the cloud.  It also supports the Memcached protocol.

Web Sites

Another PaaS feature has been added to enable the deployment of websites in just a few clicks with the possibility to create a site from a gallery of web application templates, such as Joomla!, WordPress, Drupal…. Another addition is the possibility to automatically publish changes on a website upon a successful build from a GitHub or a TFS repository.

Microsoft has packed this spring release with a lot of new exciting features, especially on the IaaS side which is now closing the gap with its competitor. Another notable change is a move towards the Open Source community with the public release of the Azure SDK source code on GitHub and the offering of Linux VMs, which, if we take a few seconds to think about it, would have been unthinkable in the past. It will be interesting to see what place Azure will now find in the IaaS landscape, and also how specific PaaS features like the HPC grid scheduling capabilities evolve going forward.