Migration to the cloud is a major step forward in the transformation of a company. Prior in-depth analysis is required if its implementation is to be justified. Indeed, before opting for cloud hosting, it is crucial for a company to evaluate the benefits and risks of such a change in the management of its operations. Advantages, strategies and solutions to be deployed, but also cautionary notes: everything must be taken into account for an informed decision. 


This article provides your company with the essential keys to ensure that your transition, if justified, takes place under the best possible conditions. 


Why migrate to the cloud?  


What are the reasons for migrating to the cloud? This is the question that every company must ask itself as a priority. Apart from the multiple benefits of migrating, giving up your existing infrastructure for cloud support should be advantageous in terms of cost and maintenance, but also in terms of your competitiveness. 


Lower costs

On-site data hosting infrastructures require monitoring, network supervision, various types of work and, more simply, a power supply and ventilation. In other words, hosting your data requires human resources and optimal operating conditions (which can sometimes mean that you have to invest in replacing costly equipment). This is a a major financial cost

Moving to the cloud effectively eliminates a number of these expenses as the provider hosting your data takes care of all the necessary infrastructure. From the provision of a single VM (virtual machine) to the provision of the software that keeps your application running, depending on the service you subscribe to with your cloud provider, the costs can be much lower than an on-site infrastructure. 



One of the undeniable advantages of the cloud is the ability to optimize the infrastructure used for your operations according to your needs. Thus, for example, if your current situation requires it (e.g. your application is more in demand than usual), you can, at any time, increase and adjust its capacities of storage and memory, as well as ts CPU instance capacities. 
However, bear in mind that any expansion of your cloud resources, any scalability of it, comes at a cost. Is it justified in terms of the needs of your application?


Cloud infrastructure management

Migrating to the cloud does not dispense with the physical equipment that hosts your data or the procurement issues that may need to be addressed. However, it is your cloud provider that now has full responsibility: this service is included, so you can focus your efforts and resources on adding value to your business! 


Guaranteed security and redundancy 

In most cases, the cloud hosting provider offers redundancy of the hard disks used to store your data: these are replicated on another storage medium. This redundancy guarantees the integrity and security of all your data in the cloud. This is a clear advantage over an on-site infrastructure.

You can even opt for more extensive redundancy through a multi-cloud deployment. Your data´s degree of importance will dictate the need for this additional cost.


Focus on business value added 

Moving to the cloud means that your company can focus on its core business. With infrastructure management outsourced and delegated to the provider, your teams can focus their energy and skills on your operational activities, and on the needs and satisfaction of your customers


More competitive

You may well be in the vanguard of migrating an operational infrastructure to the cloud (depending on your field of activity), but it's the time savings and operational gains that will be invaluable in helping you position your products on the market faster than your competitors.

Moving to the cloud can boost your competitiveness and ensure the sustainability of your business. 


Cloud solutions tailored to business needs


Each company has its own needs and for every need there is a bespoke cloud solution. Your objective is to select the most suitable solution for the part of the on-site architecture that you want to migrate to the cloud. 


IAAS (Infrastructure as a Service) 

In this cloud architecture, the company abandons its existing infrastructure for infrastructure that will be made available by the provider in a data centre. It is a minimal cloud service for companies that have all the necessary equipment in-house. More specifically, the supplier creates virtual machines on which the company itself installs its operating system and integrates its application and its database. 


CAAS (Containers as a Service) 

The CAAS solution combines the IAAS solution described above with two additional building blocks managed by the cloud provider: virtualisation and the operating system. This model is for companies that know how containers work and are already working with Kubernetes or Docker. Indeed, these container orchestration tools need the support that the CAAS solution can provide. In the same way, CAAS makes it possible to use the microservices architecture. 


PAAS (Platform as a Service) 

PAAS brings everything offered by CAAS with the addition of the runtime service. Companies and programmers interested in this model can manage their own application without concerning themselves with the infrastructure or even the platform, and the PAAS solution then provides the platform. 


FAAS (Function as a Service) 

The FAAS solution does not provide the entire software component; it provides only the environment in which the company can write its function to run its application. If no function is requested, there is no additional cost.

This cloud model, also known as Serverless, is currently very popular with developers and companies. For example, AWS Lambda, Microsoft Azure or Google Cloud Functions are cloud players offering this type of service.  


SAAS (Software as a Service) 

Finally, SAAS is the most comprehensive level of cloud model offered by a provider of cloud migration. It takes care of the management of all the software components whether it be the infrastructure, the operating system or the application.

This turnkey solution is of particular interest for small companies that are considering outsourcing the overall management of their application. Installation and scalability require human resources that not all companies have.

SAAS works through a licensing system: the user accesses their application by paying (they buy a licence). The application is updated by the supplier, who provides the company with statistical data on the use of the product. 


Risks of migrating an IS


Thus, migration to the cloud has many advantages for a company. However, it is not entirely risk-free. It is important to be aware of, and assess, the risks prior to migration and choosing the hosting provider. 


Risk assessment | Inappropriate migration

The first risk a company faces is migrating its on-site infrastructure to the cloud even if this transition is not 100% suited to its application. To avoid this risk, an internal audit is essential.

Indeed, not all on-site infrastructures justify a cloud migration. Some services may contain bugs but there may also be latency which can have a negative impact on your users' experience. In addition, some applications are not scalable in both directions, which results in an increase in the cost of the infrastructure.

Finally, consideration of risks should not neglect the human factor. A radical change of work tool can have an impact on your teams, their habits and their adaptation to these changes. For example, in some sectors such as banking, the use of a Legacy application is not suitable for the cloud. So, a successful migration requires abandoning old software for new software that is compatible with the chosen cloud solution. All these changes could be detrimental to the user teams and result in their reluctance to accept them


Choice of cloud host

This step is important because it raises the question of the security and ownership of your data. Indeed, depending on your business, some sensitive data may be even more sensitive on a public cloud. Ask yourself: what content do you want to make available? What risks are associated with this? Who might be able to access it?

In addition to your business, your geographical area (or the area targeted by your business) can also dictate your choice of cloud host. This geographical area must also comply with GDPR regulation. The notion of AZs (Availability zones) therefore acquires full importance in the analysis that you must undertake you must make a strategic choice on one or more AZs of the cloud, based on your needs.

Our consultancy can carry out an in-depth study of the cloud you have selected in order to check that its cost, its compliance with GDPR regulations (in order to avoid data being transmitted outside Europe) and its deployment mode (VM or containers) meet your needs.


Go-live and migrating to the cloud: steps, tools and strategies

Audit phase

At Alter Solutions, we support you as you migrate to the cloud. We organise validation audits to ensure that your company meets all the prerequisites and that the process has undergone internal analysis. A testing and performance phase and a survey of business teams are necessary to complete this important step.


Choice of migration strategy

The choice of cloud migration strategy will have a direct impact on the success of the project within your organization. The following are the different migration steps available to you:


  • Rehosting: with this method, the company chooses to transfer the data from its on-site infrastructure to the cloud. This is intended for companies that have opted for the IAAS solution, as the cloud provider only makes its infrastructure available;

  • Replatforming: before transferring the application, your company must create an environment to host it. This step enables you to optimise and increase the performance of your application;

  • Refactoring: is the transfer of your application and all its functionality to the cloud. This step is crucial because it enables you to observe how your application behaves after it has been transferred. Refactoring is relatively time-consuming, as it is possible that not everything works at first: rollbacks might be necessary to reach a stable and bug-free situation;

  • Repurchasing: this step consists of the final switchover of your application once its transfer is complete. To access it, you now have to go through the cloud;

  • Retire: your application is on the cloud. It is then put on standby on your on-site infrastructure until it can be removed;

  • Retain: this step involves returning the application to its initial state on the existing infrastructure (on-site). It can be applied for different reasons and it delays migration to the cloud.


Depending on your migration strategy, you may decide to switch everything over (big boom) or apply a progressive method. In doing so, you will be able to see if, and at what stage, bugs appear.

Strangler pattern, Canary release, Blue green are all migration methods that allow for a gradual transfer, effectively ensuring successful application deployment.


  • Strangler pattern, to migrate several services gradually. If you initially have a monolithic application, the migration can take place at the same time as the development of microservices from the monolith. It will then be a matter of routing until the monolith applications are offered by the microservice;

  • Canary release, to test your application. This strategy makes it possible for your application to be tested by a number of users, following its transfer, while other users continue to use the application on the on-site infrastructure;

  • Blue green, from the previous version to the new version. The application is deployed in environment 2 (secondary). When this environment has completed its deployment, the users in environment 1 (main) can be routed.



Costs are an important issue for the company to monitor. However, if the resources required by the new architecture exceed those of the old one, this may be a danger. Migrating from an on-site infrastructure to the cloud can, in some cases, be a financial opportunity in and of itself, but it is important to consider optimising your application infrastructure.

The FinOps (Financial Operations Officer) is part of this process and participates in the governance of the cloud (decision-making body that administers and secures the data transferred to the new hosting environment), an essential structure in the company. They take a close look at all flows, in order to limit cloud-related expenses - which have been rising steeply in recent years.


How can the API Gateway and Service Mesh facilitate IS migration?

The organisation or cloud support have tools to facilitate the migration of your infrastructure. In this area, two tools are of note: the API Gateway and the Service Mesh.


  • The API Gateway is used in many areas and facilitates communication between third parties wishing to use your interfaces (APIs) to access your services (your application services). The API Gateway prioritises security through access control and authentication for data transfer, including your on-site migration to the cloud;
  • Meanwhile, the Service Mesh is a network service that facilitates communication between the various microservices. It provides the common substrate for components to communicate across environments. In addition, the Service Mesh requires a consistency check, ensuring the identity and security of your data.

These two complementary tools are available on several platforms, including Istio for the Service Mesh and AWS for the API Gateway. Their use greatly facilitates migration to the cloud from an on-site infrastructure.

There are many requirements for a successful migration to the cloud. Choosing the support of a consulting firm such as Alter Solutions guarantees your company smooth implementation of this transition across all strategic stages.

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