Today, the majority of enterprises operate large traditional IT applications that were developed in a waterfall approach using a mainly monolithic blueprint . This is in stark contrast to the latest IT pattern—using cloud-native to drive the digital agenda. However, integrating or replacing traditional with cloud native applications can be a real challenge; the path for traditional (sometimes referred to as legacy) is not clear.
Introduction: Traditional applications are designed, developed and built to be operated on premise, hosted and managed end-to-end by the internal IT organization. The application design is typically based on a monolithic design, that follows a “one size fits all” approach . Typically organized in a three-tier architecture that covers a front, mid and end layer, the application is encapsulated with state, data and interface references, which can impact flexibility and agility.
Cloud-native applications on the other hand, are built to run on cloud/as-a-service infrastructure and middleware environments that operate both on and off premise. The application design is using a microservices blueprint that follows a “superfine” approach where “Independent application services delivering one single business capability in an independent, loosely connected and self-contained fashion” .
Cloud-native applications are stateless, technology independent and can be deployed in almost any context. Cloud-native is today’s choice when designing and deploying applications that are fast (in terms of deployment and change time), agile and deliver value for money.
A recent study has shown  that 15% use a cloud-native approach doubling to over 30% by 2020. This means that 85% of today’s IT landscape follows a non-cloud-native approach, only reducing to 70% by 2020.
Comparing the features and benefits of traditional with cloud-native it seems clear that cloud-native is the far superior choice. But why are organizations not adopting cloud-native faster? What are the adoption and transformation barriers and how best to overcome them?
The shift challenge: For many moving off traditional to a pure cloud-native approach is a bit like changing car at 100mph (miles per hour)—it can impact significantly security, speed as well as cost. Also for some changing car makes sense, for others it may not. The same applies a bit to cloud as well—cloud is a means to an end, and not the actual end for an organization—and to understand whether an active transformation of legacy based traditional to cloud-native is beneficial a top-down and bottom-up view is needed.
The shift considerations: The barriers to moving from traditional to cloud-native are significant; long-standing contracts with third parties, existing IT organization with limited microservices experience, cybersecurity, and data protection concerns, sunk cost in on-premises infrastructure as well as cloud-native incompatible technology.
To understand which traditional applications should be changed to follow a cloud-native approach, a number of key aspects have to be assessed: technology, security, cultural, third party as well as commercial. In detail this should entail:
- Business case:
- Moving from traditional to cloud-native must follow a proper business case the move to cloud is not always providing benefits. For example in environments where the assets are more than five yrs old, where the data center facilities are covered in a separate (to IT) budget, and/or where there is limited need for cloud-lie agility and flexibility, it can be hard to reduce opex and deliver benefits that justifies the capital expenditure.
- On-premise traditional IT:
- Successful cloud requires well-architected private cloud. Traditional IT have to transform to a private cloud to include self-provisioning, dynamic resource scaling, a chargeback model for lines of business, orchestration for automating repeatable tasks and a high-visibility management platform to monitor how and where services get deployed.
- Public cloud is not = public cloud:
- You need to treat your cloud provider selection like a COTS selection. Each cloud provider will have very different characteristics covering SLA, KPIs, APIs, monitoring, number of DCs, instance types, supported operating systems, standards, ease of migration, service age, etc. Make sure you assessed all characteristics to ensure this is the right platform.
- Ensure you are covering all aspects from user identification, authorisation and authentication, to data and network encryption, intrusion detection as well as clear separation with co-hosted services.
- Latency and bandwidth issues, chatty applications, network topology, network security, extending local topology to the cloud.
- Data and application integration:
- Throttling of inbound queries, data move, inter-dependencies and impact of remote host is not necessarily available.
- Service, system, release and change management:
- Configuration management, patching, capacity planning and monitoring, system monitoring, etc.
- Moving machines, metadata and configuration.
- Cultural shift for people, skills are in high demand, so difficult to find, require architecture skills. Also for existing staff the shift from traditional to cloud-native is significant (see below).
Cloud-native is not just changing the way applications are constructed, but also how they are being deployed— traditional follows a monolithic and waterfall approach, whereas cloud-native follows a microservices and agile approach.
Applying a cloud-native approach is not just a technology shift, it first and foremost requires a very different set of skills and cultures than a traditional approach. A recent study  outlined five key challenges CIOs and IT managers cited when moving from traditional to a cloud-native approach:
When comparing organizations that have/or that are accelerating the shift to cloud-native and organizations that lag behind, people skills and cultures are more important than the actual technology shift.
Summary: Software is the new gold; increasingly organisations apply a digital first approach to differentiate where cloud-native is the prevailing blueprint for today’s digital application landscape. Organizations that retain their existing traditional landscapes may stay behind, and the decision to transform the existing traditional landscape to a cloud-native paradigm has to consider many factors—for some an active and wholesale shift from traditional to cloud-native is the right path, for some leaving the traditional As-Is plus to apply a cloud first for only new applications, and for others a mixed approach is the right way forward. Deciding the right path requires a detailed assessment covering people, process and technology.
Thanks for reading.
About the Author: Gunnar Menzel has been an IT professional for over 29 years and is VP and Chief Architect Officer for Capgemini’s Cloud Infrastructure Business. His main focus is business—enabling technology transformation and innovation
References :  www.capgemini.com/cloudnative,  Microservices in cloud-based infrastructure, Gunnar Menzel, June 2016, https://www.capgemini.com/resources/microservices-in-cloud-based-infrastructure,  Existing application cloud migration; what are the options?, Gunnar Menzel, June 2017, https://www.linkedin.com/pulse/existing-application-cloud-migration-what-options-gunnar-menzel