Migrating Legacy Applications to the Cloud: A Practical Guide

While these apps are critical to businesses, they are often built on old technologies, which makes them incompatible with newer cloud-based environments.

On top of that, they can become obsolete, outdated or unreasonable to maintain via an on-premises data centre. That is why many businesses choose to innovate by moving their legacy application to the cloud.

Why go to the cloud?

Cloud migration is increasingly attractive for those legacy systems looking to reduce IT costs and foster innovation and business growth.

With cloud environments, there’s no need to guess capacity or over-purchase hardware for peak usage. Besides, it eliminates spending money on running and maintaining physical data centres.

You should consider a cloud migration because being on-prem likely holds you back:

• IT maintenance takes away much from your time
• Obsolete hardware
• Failures occur often
• Hard to scale down
• Not focusing on key business projects

What are the benefits of migrating legacy systems?

Moving legacy systems to the cloud can provide you with the following benefits:

Cost savings

Moving legacy apps to the cloud can save you money as it will offload you from managing physical infrastructure, maintenance and hardware management. With cloud providers, you only pay for what you use, and you reduce capital expenditures. The public cloud is more efficient and, therefore, much cheaper.

Improved system performance

With growing user expectations, who expect nothing less than constant availability of services these days, legacy systems often become sluggish and unreliable, resulting in bottlenecks and slowed-down business operations. 

Because let’s be honest: legacy applications were never built to handle today’s modern business needs.

On the other hand, cloud platforms like Microsoft Azure are designed for performance so you can meet changing customer demands.

Scalability (automated scaling)

In the cloud, you can scale up or down as needed so you can save big on IT costs and meet fluctuating (up and down) customer demand. If you want to deploy 1 or 10 Web Apps tomorrow, you can – anywhere you’d like.

Do you need less? Then simply scale down again. In legacy systems, you have to arrange this yourself. You buy servers, but if you want to scale down, you still have too many in-house. Unnecessarily expensive and not efficient.

And as if that wasn’t enough, auto-scaling in the cloud means your system can handle spikes and fluctuations in traffic without you having to lift a finger. 

Compliance

Cloud providers have built in compliance tools and services to help you meet industry regulations and data privacy requirements. By moving to the cloud you get automatic updates so your systems stay compliant with changing standards like GDPR, HIPAA and more.

So legal requirements don’t have to be a burden on your internal teams and sensitive data.

Business agility

The cloud lets you deploy apps and updates on the get-go so you can keep up with market changes and roll out new features without the usual delays which often come with legacy systems.

Outsourced infrastructure management

As securing, managing and scaling on-premises infrastructures can be challenging and far from cheap, you can offload this burden by migrating to the cloud.

Do you run a legacy application but find securing or maintaining the infrastructure challenging? Then, a move to the cloud can benefit you, especially with Platform as a Service (PaaS). 

You leave the infrastructure management to these cloud providers (everything from hardware to data centres), which frees your team to focus on critical tasks and business innovation – not routine maintenance and troubleshooting.

Disaster recovery

Built-in backup and recovery means your data is safe and can be restored quickly in case of an outage, with minimal downtime and business continuity.

Enhances security

Having a legacy application not only means you’re left with outdated technology but also causes security threats as they often rely on outdated security measures.

Migrating them to the cloud gives you access to robust security measures such as real-time threat monitoring, encryption, automated updates, etc, offering protection far beyond what most legacy systems can manage.

Availability

The public cloud is available worldwide and is also used by millions of business owners and organisations worldwide. It is therefore efficient, but also reliable. Millions of people worldwide are involved, with improvements, innovations, and knowledge benefiting all users.

Dynamic

The cloud is dynamic. In the past, you bought something and then went with it. Whether you were satisfied or not. You had bought it, so you used it. But if you're dissatisfied with a cloud service, you pick up your bundle and leave. As a result, the best services stand out and can evolve.

Inbuilt features and services

Clouds have built-in services like AI, machine learning, analytics, and advanced monitoring, so you don’t have to build them from scratch.

Flexibility

Cloud computing is way more flexible than legacy systems, and you can access it from anywhere on any device. This means a mobile workforce, employees, and customers can access applications and services anywhere. Cloud makes it easier to add new tools, so you can adapt as you grow.

Sustainability

Many cloud providers focus on energy-efficient operations and sustainability, helping businesses reduce their environmental impact using shared infrastructure. For example, Azure’s liquid immersion cooling technology helps lower server energy consumption by 5 to 15% while minimising water use in data centres. 

Nevertheless, new vulnerabilities and risks can come to light when you migrate from on-premises to the cloud, which we will discuss later. So keep on reading.

7 steps for migrating legacy applications to the cloud

The steps below are general steps; each organisation is different, so a one-size-fits-all won’t work.

The actual steps required to migrate your on-premises environment will depend on:

• The complexity of the application
• Business goals
• Staff expertise
• Available skills and resources
• Overall IT landscape

Moving on-premises to the cloud won’t work without a cloud migration strategy and understanding the application you want to move.

Here are 7 steps for migrating your legacy application to the cloud.

Step 1: Conduct a SWOT Analysis

Start with a SWOT Analysis to fully understand the strengths, weaknesses, opportunities and threats the migration poses to your business. It will give you clarity on the key factors impacting your organisation.

In a continuous development environment, you shouldn’t assume it’s “set in stone” once the SWOT is done. Instead, you should update it to reflect changing circumstances, new risks and opportunities as the project progresses.

The SWOT will tell you if your team is ready to move the application and what needs to be addressed, like compliance or extra training.

Step 2: Assess

Before you start to migrate, you need to know what you want and what you have. That means understanding the application portfolio to see which options are simple to get off the legacy platform, simple to get up, and low cost. Those will drive out hardware and operations dependencies. 

Then, as you look at the more complex ones, you must assess the right path. Different approaches can work; there’s not just one approach.

Before migrating, we need to deeply understand the current architecture, including the mapping of applications and their dependencies. 

Also, we must consider the limitations and risks of the migration:

• Operational risks: the service disruptions and performance issues during migration.
• Financial risks: these are unexpected costs like licensing, third-party services or scaling costs.
• Security risks: around cloud data protection and regulatory compliance.

In addition, consider the risks of not migrating – high maintenance costs and limited scalability of old systems. This will help you make a decision and mitigate potential issues.

Consider assessing these things:

• Your capacity
• Your network architecture
• The performance requirements of your old and new systems
• The resilience of both new and legacy systems

Always start by asking yourself:

• Why do you want to move to the cloud?
• What are the main reasons for this? Is it scalability, reliability or security?

Get this clear upfront, as this will impact your strategy and approach.

Assess skills of staff and competencies

What’s more, you need skills and cloud competence for a successful cloud migration. Evaluate available staff and development resources, identify gaps, and devise a strategy accordingly.

Can you do it in-house, or is outsourcing required? You must answer that crucial question before taking any significant steps in the cloud migration journey.

Determine your target architecture

Although this is a migration, you must define your solution architecture or equivalent architecture design. Significant changes may be required if the legacy application was built many years ago.

Step 3: Create a Strategy and Roadmap

The third step is to choose a strategy. This strategy should be based on your goals and resources and focus on effective cloud migration strategies.

There are many migration strategies to choose from, but the right strategy depends on your:

• Resources
• Size
• Complexity
• Application's nature
• Your goals

These are the strategies, also known as 6Rs:

1. Replace/retire
   Replace means getting rid of an old system with a new one and retiring it altogether for when it’s no longer needed. This is for old systems that became obsolete, redundant or no longer serve their original purpose. 
2. Retain
   Retaining is when you decide not to move specific systems to the cloud and remain on-premises. Sometimes, it's cheaper to keep systems on-premises because of security or performance concerns.
3. Re-host/Lift and shift
   Also known as "lift and shift", this strategy means moving systems to the cloud without changes. (moving systems from a data centre to the cloud without changing the application). It’s low-cost and suitable for a multi-cloud environment, yet it doesn’t let organisations benefit entirely from the cloud’s features.
4. Replatforming/Lift and Reshape
   It comes with some optimisations for the cloud. At the core, you're mainly migrating your systems to the cloud but taking advantage of certain enhancements in some areas. This is your go-to option if security and compliance are your main drivers. 
5. Refactoring/Re-architecting
   This is a more involved cloud migration process that requires modifying code. Refactoring typically involves rebuilding applications from scratch, specifically for the cloud. It lets you fully leverage Cloud Native services, such as serverless computing. It can be expensive and time-consuming but offers long-term benefits. Legacy apps in Java are great for refactoring as these are challenging to scale, update and maintain.
6. Repurchasing
   Repurchasing means moving your applications to a new Cloud Native product. Here, you buy a different version of what you have, often in the form of a SaaS application. 

Then there’s more to consider, such as a timeline, budget, resources required to migrate, risks and pitfalls and how you will mitigate them.

Step 4: Choose a Cloud Type and Vendor

Think about which type of cloud suits your application most for the migration. This can be:

1. Public cloud
2. Private cloud
3. Hybrid
4. Multi-cloud

Public clouds (1) such as Azure offer cost-effective solutions and scalability. On the other hand, private clouds (2) can give you the best control over your data and security; these are more fitting for industries with strict compliance. A hybrid cloud (3) combines both to balance your sensitive workloads between private and public environments. Multi-cloud (4) allows you to use multiple providers and leverage each one's strengths based on the application or business need.

Another critical decision is deciding which cloud vendor you want for your application.

There are a lot of choices in terms of cloud vendors as of today, but it should hinge on whether the vendor makes the most sense for the application.

Step 5: Run a Pilot Migration

Before fully migrating all your legacy applications, you should run a pilot to test out your methods. In other words, migrate a portion to check whether issues occur.

In an ideal world, you execute this in a simulated setup. We can also call this a “test phase”. Consider doing this for non-critical or smaller-sized applications. 

Test the migration process and evaluate the impact on your infrastructure, operations, and team. You can also collect end-user feedback to find things that do not work as before. Do not forget also to configure monitoring tools.

Step 6: Migrate the Legacy Application

Successful legacy application migration can start when you have tested (and passed) methods, a chosen strategy, and planned the migration.

But even when you have everything planned and mapped out, we can’t rule out the unexpected. You need a backup plan, like having a full backup of all data and apps. Also, think about a rollback plan where you outline the steps to roll back the legacy app to its previous state.

Also, you can do incremental migration. Here, you migrate small parts at a time, which can help minimise risk and make the migration process more manageable.

Step 7: Evaluate the Outcomes and Monitor

Evaluation is ongoing progress as you evaluate during your assessment, testing phase, and during and after migration. After migration, work may still be left to tackle issues or improve application performance. 

Some users may encounter problems or functions that did not work as before. You may have achieved only parts of your goals, which is why continuous monitoring and optimisation are crucial. 

Evaluate the outcome by reviewing the system’s performance to ensure it aligns with your business goals, such as cost savings and scalability. Set up continuous monitoring tools to detect any performance, security, or compliance issues in real-time. 

This is just a general view of a legacy application migration process, and most legacy migrations are complicated and time-consuming.

Challenges of migrating legacy applications (and how to solve them)

Migrating legacy applications to the cloud offers many benefits but can be a road full of unexpected twists, turns, and roadblocks.

Costs

One of the biggest challenges around moving legacy apps to the cloud is their associated costs and effort.

Downtime

Minimising downtime during the migration is a real challenge. This can be very risky, as downtime costs should not be underestimated. To toss in more, data loss is also one of the greatest risks when moving a legacy app to the cloud. This is especially true for applications with poorly structured data, which are more vulnerable. 

To mitigate these risks, you can:

• Use cloud services like Azure Site Recovery to ensure business continuity by failing over workloads to the cloud during migration.
• Spread workloads across multiple regions to reduce the impact of outages, ensuring customers experience little to no disruption. 

Not open to change

Many (older) users feel comfortable with legacy applications because they have used them for so many years. As a result, they may become resistant to change and adapt to new technologies. 

Decision-makers can also hesitate to upgrade or adopt modern technologies because they fear disruption to familiar processes embedded in the company’s culture.

Lack of expertise and skills in (aged) Old Applications

Legacy applications can be named “old”, while some may be in the system for decades.

Let’s not get around it: most of these have been developed with old technologies, while these developers may have retired from the system or left. 

Modern developers may not understand the original codebase because they don’t have expertise in outdated programming languages or frameworks. So they can’t decode or interpret it. Without documentation or someone who can pass on knowledge, teams will spend a lot of time reverse engineering and optimising these applications for the cloud.

Change Management

Change in management is crucial in any digital transformation, especially for cloud migrations. Going to the cloud means more pressure on changing your people and processes to fit the technology rather than changing the technology to fit your existing processes. At least, if you want to get the most out of it, that is to say, more focus is required on change management.

Organisation Culture

Organisational culture can be seen as one of the greatest challenges when moving legacy apps to the cloud. Developers and engineers want to focus on developing and innovating. So, application developers constantly innovate, whereas operational teams are trying to maintain a stable production environment. 

Then again, these are just some key considerations when developing your cloud migration strategy.

Pitfalls of migrating to the public cloud

When you migrate to the public cloud with your application, data, and workloads, you want everything to go right. These are often pitfalls when migrating to the cloud.

• Seeing migration as an expense: First, viewing migration as an expense rather than an investment is a common misconception in cloud migrations.
• Relying on inexperienced staff: Second, relying on staff that have simply never done it before.
• Overanalyse and under-analyse: The first leads to increased cost and might never get the project off the ground, and the second leads to weeks, months, and even years of clean-up and spiralling add-on expenses.
• Underestimating the cost of migrating to the cloud: While moving to the cloud reduces the upfront costs of servers and physical space, it’s easy to underestimate the long-term costs. (Hidden costs like licensing fees, third-party integrations and the need to scale can add up over time and make the cloud more expensive than you thought).
• Expecting too much from an lift and shift migration: Migrating your IT environment via lift and shift, the one-to-one transfer of resources, often results in a complex and expensive situation. It is a common mistake today, not taking into account the architectural principles of cloud providers. You should translate your functionalities to the cloud’s design standards.
• Not having a mindset for automation: Automation plays a big role in the cloud. You can basically automate almost anything. That is why we need to use and embrace automation. It helps us streamline processes from start to finish. With automation, you can free your developers to focus on valuable tasks for the business.
• No consideration of a fall-back scenario: Numerous factors can lead to the disruption of a migration. However, when resources are migrated, a fall-back scenario is often not taken into account. It is therefore advisable to have a fall-back scenario available at all times. This way, continuity is guaranteed.
• Not having a detailed migration plan: A migration without the right experience may lead to loss of functionality, long downtime, and failure to meet the right compliance issues. 
• Not understanding Cloud Capabilities: Legacy apps are not designed to use Cloud Native technologies like ML, AI and IoT. Companies rushing into the cloud without fully leveraging these capabilities may miss out on substantial business agility and innovation improvements.

Closing thoughts

Migrating legacy applications to the cloud is not just a technical shift. Instead, it’s a strategic decision that involves careful planning, resource allocation, and organisational change.

Anyone who wants to hitch a ride on the latest developments no longer needs to invent it themselves but can simply enter via the cloud. 

Therefore, the question is not whether to opt for the public cloud but when.

Staying on-prem or adopting the cloud: what will you choose?

While the pitfalls mentioned speak for themselves, many companies are left with obsolete legacy apps, including outdated systems where adding new technologies is as hard as squaring a circle.

But let’s face it: staying on-prem is not getting you further either, as you’ll remain stuck to limits. Many legacy applications can no longer scale, and the costs increase while the performance decreases. 

While a cloud migration from legacy systems to the cloud can fail for several reasons (poor planning or choosing the wrong migration strategy being the most obvious ones), the costs of not migrating will likely be higher.

But this is where your cloud partner, like Intercept, can help you when you want to move your legacy app to the cloud.