AI-Powered Continuous Integration and Continuous Deployment (CI/CD)
Date: 05/11/24
By: Krzysztof Lewczuk
In an era where business agility and technical resilience are more crucial than ever, organisations are increasingly embracing cloud migration as a strategic driver. This journey not only offers enhanced scalability, security, and cost efficiency but also propels businesses towards a future-proof infrastructure. Whether transitioning from on-premises to cloud, switching between cloud providers, or moving from cloud back to on-premises, the process is underpinned by critical considerations surrounding the “why,” “where,” and “how” of cloud migration strategies.
This article, from Senior Consultant Roxana Necula, delves into these questions, offering insights into the objectives, destinations, and strategies that shape successful cloud migration paths. Through exploring common motivations, comparing migration types, and evaluating the 5Rs framework (Rehost, Retire, Repurchase, Refactor, and Rearchitect), she lays out an introductory guide to navigating the complexities of cloud migration.
– Rajesh Jethwa, CTO, Digiterre
We now see organisations more often go through cloud migration processes with their applications. That usually requires extensive planning and preparation and, in this process, the teams in charge usually address three important concerns:
The factors leading to the need for migrating can blend, or shift in importance over time for organisations, shaping how the process unfolds. There are many out there, but here are the most common reasons we encountered so far:
The “WHY” leads to the “WHERE” to migrate: from on-premises to the cloud, between one cloud provider to another or take the infrastructure from the cloud back to on-premises. Here is a table of comparison between these types of migration, considering cost, scalability, reliability, performance, security, flexibility, and maintenance.
Aspect | On-Premises to Cloud | Cloud to Cloud | Cloud to On-Premises |
Total Cost of Ownership (TCO) | Lower | Moderate | Moderate |
Scalability | Higher | Higher | Lower (depends on infrastructure capabilities of the on-premises) |
Reliability | Moderate | Moderate | Moderate, but depends on the quality of on-premises hardware and maintenance |
Performance | Higher, with the ability to select optimal cloud resources | Higher | Lower (depends on the quality of on-premises hardware and maintenance) |
Security | Higher | Higher | Lower |
Flexibility | Higher | Higher | Lower |
Maintenance | Lower | Lower | Higher |
Whether migrating from on-premises to cloud, between cloud providers or back to on-premises, there are several strategies available that serve as a guiding compass, such as the 5Rs framework introduced by Gartner (a global research and advisory company): Rehost, Retire, Repurchase, Refactor and Rearchitect. The comparison below highlights the key differences between these strategies ordered by complexity and time to implement, including their descriptions and key concerns.
Migration Strategy | Rehost (lift and shift) | Retire | Repurchase (replace) | Refactor (rearchitect) | Rearchitect (rebuild) |
Description | Move applications as-is to the cloud without making any changes | Decommission or phase out applications that are no longer needed | Replace existing applications with commercial off-the-shelf (COTS) solutions or SaaS offerings | Optimise applications for cloud environment without changing their core functionality | Completely redesign and rebuild applications for cloud-native architecture |
Applies to which migration type | On-Premises to Cloud | All | On-Premises to Cloud and Cloud to Cloud | All | All |
Complexity | Lower | Lower | Moderate | Moderate | Higher |
Time to Implement | Faster | Faster | Faster | Moderate | Time-consuming |
Cost (CapEx) | Lower | Lower | Higher | Moderate | Higher |
Cost (OpEx) | Higher | Lower | Moderate | Moderate | Moderate |
Flexibility | Limited | N/A | Limited | Moderate | Higher |
Performance | Moderate (maintains legacy performance characteristics) | N/A | Moderate (depends on the replacement solution) | Higher | Higher |
Scalability | Moderate | N/A | Moderate (depends on the replacement solution) | Moderate | Higher |
Risk | Lower | Lower | Moderate | Moderate | Higher |
In the lifecycle of a long-lived application, it is common to traverse through multiple stages of migrations, either sequentially or concurrently, based on evolving business needs and technological advancements.
For instance, an application initially hosted on-premises may undergo the Rehost phase, where it is lifted and shifted to the cloud infrastructure without significant modifications. As the application matures in the cloud environment, organisations may opt to Refactor certain components to optimise performance or scalability. Subsequently, they might Revise specific functionalities to align with changing business requirements. Over time, the application might undergo a complete Rebuild to leverage cloud-native services for enhanced efficiency and innovation. Eventually, organisations might decide to Replace the application entirely or parts of it with a cloud-specific or newer solution.
This iterative journey exemplifies how applications can transition through multiple stages of migration, adapting to the evolving landscape of technology and business demands.
If you would like to know more about Cloud migration strategies visit our Services page or Contact us.
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By: Krzysztof Lewczuk
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