Cloud migration: the 9 key steps for a successful migration

More and more companies are choosing the cloud when they want to evolve their infrastructure. This trend, already occurring for several years, is accelerating. Cloud migration promises greater efficiency without increasing the technical management burden. But what does it really entail? How should you proceed, and what mistakes should you absolutely avoid? Read on.

What does “Cloud migration” mean?

Cloud migration refers to the set of actions a company takes to transfer its IT resources, servers, applications, databases, files, and business software, to internet-hosted infrastructure, rather than keeping them on-premises.
Instead of purchasing and maintaining physical servers locally (on-premises infrastructure), the company rents resources on demand (computing power, storage, software, etc.) from a cloud provider such as AWS, Microsoft Azure, Google Cloud, OVHcloud, etc.

The three main types of cloud

Il existe trois grandes formes de cloud.

• Public cloud: shared infrastructure hosted by an external provider (such as Amazon Web Services, Microsoft Azure, Google Cloud, OVHcloud…), and shared by multiple clients who remain isolated from each other.
• Private cloud: dedicated infrastructure for a single organisation, either on-premises or hosted externally exclusively for that client.
• Hybrid cloud: a combination of public and private clouds, allowing the company to choose where to host each resource based on sensitivity, performance, or compliance requirements.

The three cloud service models

• IaaS (Infrastructure as a Service): rent raw IT resources such as servers, storage, networks, and firewalls, essentially a remote data center without purchasing or managing it physically.
• PaaS (Platform as a Service): a ready-to-use development platform where you don’t manage servers or databases, you just develop your own applications while the provider manages the underlying infrastructure.
• SaaS (Software as a Service): access ready-to-use software via the internet without local installation, typically on a subscription basis.

Why choose cloud migration? What are the benefits?

Companies today face constant pressure to innovate faster, reduce costs, and deliver digital products faster. Traditional IT systems based on local servers can quickly reveal their limitations:

• high maintenance costs;
• limited scalability;
• restricted remote access;
• low agility.

Cloud migration is more than just a technical choice, it’s a strategic choice, changing how IT is consumed, managed, and valued.

Benefits include:

• Cost efficiency: pay only for what you use, no need to pre-purchase servers.
• Scalability: adjust resources instantly without buying new hardware.
• Remote access: tools, files, and applications available anytime, anywhere.
• Security: cloud providers invest heavily in encryption and advanced security.
• Access to advanced services: machine learning, blockchain, IoT, etc.
• Reduced operational burden: no manual server restarts, security updates or midnight troubleshooting - the provider handles the infrastructure.

When to prioritise cloud migration

Migrating to the cloud can offer numerous benefits, but this does not mean that every company should do it or do it immediately. It all depends on your constraints, business challenges, and your level of IT maturity. Cloud migration could be the right solution in several scenarios:

• Your current infrastructure is outdated or undersized.
• You are developing a new service or application (to start quickly, test rapidly, and adjust resources based on the project's success).
• You are adopting remote work or working with remote freelancers
• Your activity is subject to workload peaks or fluctuations.
• You need to strengthen your security and improve your backups (migrating to the cloud can provide security, redundancy, and disaster recovery guarantees that are often superior to those available with local management).
• You are an SME or a startup without a full IT complement.
• You are subject to compliance requirements (GDPR, HDS, ISO, etc.) and cloud infrastructures often provide certified environments.
• You want to innovate faster.

Step-by-step guide to cloud migration

1. Conduct an audit of your current setup

Before making any decisions, the first step is to perform a comprehensive assessment of your current IT infrastructure. This allows you to identify:

• what can (or cannot) be migrated;
• priorities;
• technical dependencies;
• potential risks.

To do this, you can conduct interviews with IT and business teams, analyse existing technical documentation, or even use automated auditing tools to map systems (such as AWS Migration Evaluator, Azure Migrate, etc.).
This work will help you identify priority or incompatible applications, estimate the budget, define a realistic timeline, and determine the most appropriate migration strategy.

2. Define migration objectives

Once you have defined and understood your current environment, you need to clearly state the reasons for migrating to the cloud. This strategic step will help to:

• align technical and business teams;
• prioritise actions;
• measure project success.

You can do this by drafting a simplified requirements document or a statement of intent, defining a few key performance indicators (KPIs).

3. Choose the cloud model

Once migration objectives are set, you must choose the cloud model that best fits your context (private, public, hybrid). This decision will impact costs, security, performance, and your ability to scale over time.

To make a decision, you can:

• Compare your objectives (step 2) with those offered by each model;
• Consider your constraints (security, budget, IT team, compliance, etc.).

4. Select the best provider

Now that you have chosen a cloud model (public, private, or hybrid), you need to select the provider who will host your services and data. This is a strategic choice because it determines:

• your usage costs;
• your level of support;
• long-term scalability and flexibility.

Major providers include:

• Scaleway
• OVH
• Amazon Web Services (AWS)
• Microsoft Azure
• Google Cloud Platform (GCP)

Key points to monitor:

• Regulatory compliance of the provider;
• Usage costs;
• Service catalogue;
• Ease of migration and administration;
• Support and guidance (SLA levels, local-language support, documentation, etc.).

5. Define the migration strategy

Defining a migration strategy means choosing how you will transfer your applications, data, and services to the cloud. There is no single approach, multiple methods exist depending on technical constraints, available resources, and the level of transformation desired:

• Rehosting (Lift and Shift): move servers or applications as-is to the cloud without modifying their functionality.
• Replatforming: make slight adaptations before migration (e.g., switch the database to a managed version).
• Refactoring: rewrite or transform the application to exploit cloud services natively.
• Retiring: decommission obsolete or unnecessary systems instead of migrating them.
• Retaining: keep some applications or servers on-premises (non-migrated), often for legal, technical, or economic reasons.
• Repurchasing: replace internal software with an equivalent SaaS solution.

In practice, most companies combine multiple strategies depending on the situation.

6. Plan the migration

At this stage, you can implement a concrete action plan for the cloud migration. Remember that migration is not done all at once or in an “all-or-nothing” manner. You need to prioritise, break down, test, and progress gradually:

• Define the scope of migration (which applications, data, and services will be migrated?).
• Establish a realistic timeline.
• Identify dependencies (should some applications be migrated simultaneously?).
• Allocate resources (who does what, budget, which services will be used for migration?).
• Plan tests and checks to ensure everything works as expected.

Also consider internal communication for informing users of potential impacts and prepare guides or tutorials as necessary.

7. Conduct a pilot migration, then a phased rollout

Before moving your applications or data, you must create and configure the cloud environment in which they will run. Once this is done, perform a pilot migration to validate key points under real conditions:

• the cloud environment functions correctly;
• migration procedures are reliable;
• performance and security meet expectations.

If the pilot is successful, you can roll out migration to the entire system, ideally in controlled phases to reduce risks and minimise the impact on users. You can organise a progressive migration by business unit, data type, application, or entity.

8. Validate functional and technical points

Once a service or application is migrated to the cloud, it is crucial to verify that everything works correctly, both technically and functionally. An error-free deployment does not ensure it is fully operational for users.
Conduct technical tests, functional tests, and gather user feedback. This step will help detect issues before they become critical and ensure that migration has not degraded service quality.

9. Train teams for the change

Migrating to the cloud is not just about moving data or servers; it also changes how teams work, access tools, and interact with the IT system.
Even if the migration is technically successful, it can fail if users do not start using the new tools. Potential risks include:

• teams losing productivity;
• circumventing the system (using insecure tools);
• completely rejecting the change due to a lack of clear training.

Therefore, provide continuous training and provide manuals to support adoption.

Cloud migration: mistakes to avoid during migration

Cloud migration can bring many benefits but also entails risks if poorly prepared or managed. Key concepts to remember before, during, and after migration:

• thinking that migration is just “copy and paste to the cloud”. Even with a simple strategy (such as lift-and-shift), dependencies, expected performance, security, access, and business impacts must be analysed.
• Not to neglect security: in the cloud, security is shared. The provider secures the infrastructure, but you are responsible for what you store in it.
• Choosing an unsuitable provider. Not all clouds are equally good for all needs. Some are more data-oriented, others more suitable for office tools, and others for development.
• Not controlling production costs. “The cloud is cheaper” only if managed properly! Poor initial configuration can lead to overconsumption and higher bills.
• Forgetting to involve users.
• Failing to plan a rollback. Always plan a fallback for each migration phase.

Finally, remember that work does not end after migration. The cloud requires ongoing management: security, cost, performance, updates, regulatory changes, etc. Establish a post-migration monitoring plan with tools and regular reviews to track activity and costs.

Obtaining professional help for cloud migration

Cloud migration cannot be improvised. If certain steps are not provided for, you risk technical issues, security vulnerabilities, team impacts, or uncontrolled costs. It is therefore best to work with professionals specialising in this field.

Kaliop has made cloud migration its specialty. We can assist at every stage of your project, from the initial audit to production deployment. Benefit from a tailored approach and our recognised expertise in public, private, and hybrid clouds, as well as the DevOps culture.

If you would like to speak with a member of our cloud team, schedule an appointment via our contact form..