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Cloud category selection | STORM Clouds Services

Roadmap about migration of public services into the cloud

A step by step roadmap for Public Authorities to help them as they plan, determine effort and budget, select the appropriate services, make the required internal organisational changes and finally execute the migration into cloud.



Cloud category selection

Public Authorities should consider, when they plan their Cloud strategy, the different service categories of Cloud Computing. The majority of documents that exist online provide a detailed description of the prevailing categories, which may altogether be referred to as the Cloud Computing Stack: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), Software as a Service (SaaS). A simplified description of what each one of these categories entails is that a) SaaS applications are designed for the end-users and are delivered over the web, b) PaaS is the set of tools and services designed to make coding and deploying these applications in a quick and efficient way and c) IaaS is the hardware and software (servers, storage, networks, operating systems) that powers all the above (Kepes, n.d.).

Each of the above services has its own specific implication for the public authority that is using it. The most popular and useful SaaS-based cloud opportunities for public authorities include collaboration, document management, content management and project management (Schwartz, 2011). SaaS describes the most abstract layer of the cloud stack and it is more suitable if the organisation wants ready-made online applications. However, SaaS cannot be applied in the case that theif Public Authorities want to deploy their existing applications to a Cloud Environment. Usually, most common choices among public authorities is a combination of SaaS and IaaS as public authorities first concentrate on the infrastructure (Bonneau et al., 2013). If Public Authorities want to migrate their own applications to the cloud, they have to select between IaaS and PaaS. Both IaaS and PaaS enable the extension of platforms so that public authorities’ IT can respond proactively and reactively to increased demand for services at a lower cost (Vmware, 2011). To decide which of the two options (IaaS or PaaS) they will follow, the Public Authorities should evaluate the pros and cons of each solution.

On the one hand, the IaaS offers excellent flexibility, as it does not require architectural changes to the applications, and full control of the resources used for the deployment. However, it increases the deployment complexity, as the application owners must take care of installing and configuring all the components for high availability and scalability.

On the other hand, the PaaS “hides” the complexity of the underlying infrastructure and allows developers to deploy their web applications to the cloud without having to take care of the infrastructure. The PaaS provider usually offers the cloud infrastructure and manages levels of scalability, software upgrades and maintenance. However, the applications may require significant changes to comply with the PaaS principles and take full advantage of high availability and scalability features. In particular, as application instances are ephemeral and can be started, stopped or fail at any time, they must be stateless and share nothing. More about the selection of cloud service category can be found here.


Before selecting a cloud service category, public authorities have to examine the following issues:

  • Ownership of the applications
  • Level of infrastructure management
  • Interaction with external digital services
  • Technical assessment of the services to be migrated (operating system, language, database)
  • Management of sensitive data