To make a decision on moving from on-premise to cloud, first of all, you need to assess the capacity and type of infrastructure that the company needs. For this, a list of necessary services is drawn up and the computing power required for the proper operation of each of them is estimated.
The next step is to determine how to move data to cloud storage and when to complete it. Usually, this procedure is performed by the data center since it allows you to upgrade services and perform migration seamlessly – that is, without interrupting business processes.
Some existing systems are not eligible to migrate to cloud computing. Those are:
- Electronic security keys.
- Systems that require high performance to operate correctly.
- Software with licensing restrictions.
- Services without prior testing.
- Programs that require physical hardware to run.
- Systems requiring increased security.
There are 3 main scenarios for cloud application migration:
- Full migration. This means that the created infrastructure is transferred from the on-premise to cloud: existing data, applications used, saved settings, etc. At the same time, it is necessary to save or recreate terminal stations through which company employees will gain access to services. This method is usually chosen by small and medium-sized businesses with a fairly simple IT infrastructure. Data transfer and applications migration is done in a couple of days. The approach has minimal risks and requires minimal resources for implementation, but does not always allow for full utilization of the capabilities of the cloud service.
- Partial migration to the cloud. In fact, this is a hybrid model that assumes transferring only a fraction of information resources and systems to a cloud service. Some services remain on the organization’s own physical capacities for security purposes. This organization model is often chosen for testing and working with cloud technologies. In the case of satisfactory results of the partial migration, the transfer of all information to the new virtual platform is carried out in stages. A so-called roadmap of migration procedures is drawn up, which allows for the transfer of services without delaying business processes. This option is suitable for a large company with several remote offices.
- Parallel-optimized migration. Such application migration to the cloud implies a simultaneous transformation of the structure of the system. For example, the way applications interact with the database may change. Other changes are also made to take full advantage of the cloud.
In the event of termination of the previous licensing or the repurposing of services, it is also possible to use a new product. This solution is often chosen when migrating email, etc.
There is no single time frame for on-premise to cloud migration. The process is built individually and depends on individual criteria. If a seamless migration is needed, that is, a transfer without the downtime of information systems, then this is taken into account at the planning stage and reflected in the work schedule. A company that plans to migrate all or part of its IT infrastructure to the cloud can develop its own migration plan or use a generally accepted scheme. In any case, it needs to be finalized taking into account the specifics of the business, the volume of data, the principles of working with them, the presence of a geographically distributed network of offices, and other factors. The generally accepted scheme can be broken down into several typical steps.
Inventory allows you to assess the current volume of the company’s IT infrastructure, highlight priority components, and establish relationships between them that need to be taken into account in the migration process. During the inventory, you can find problem areas that require maximum attention during the transfer of data and services.
Migration to the cloud is available in three models:
Public cloud: The hosting provider provides cloud services to a large number of customers, and the computing, networking, and storage resources are located in one large (or several) data center. A public cloud is needed wherever flexibility and automation of routine tasks are required. Often the owners of websites and online services, and companies that develop and test software are interested in such a service;
Private cloud: the company builds its own cloud infrastructure and the resources on which the services in the cloud will run belong only to it. Large companies with extensive IT infrastructures and who work with confidential data or the state are most likely to benefit from a private cloud;
Hybrid cloud: a symbiosis of private and public clouds, where the exchange of data between them is strictly controlled by the company. Hybrid cloud is beneficial to use where the business is faced with sudden surges inactivity (for example, during sales or advertising campaigns), where it is required to implement complex technological solutions after preliminary testing, where it is necessary to test the operation of IT infrastructure elements or where new software products are being developed.
After choosing the appropriate model for the on-premise to cloud migration, calculate the need for resources: the computing power of the processors, the type and capacity of the drives, the width of the Internet channel, the number of IP addresses, etc.
Choosing a provider is one of the most critical tasks at this stage of preparing for migration. It is necessary to make sure that the provider is reliable, has the appropriate infrastructure, invests resources in its development, offers exactly the services and tools that the business needs. Ideally, the provider gives the opportunity to take advantage of the test period and assess the potential of its site on real or test projects.
Enter into a service level agreement or SLA. The leaders of the cloud market indicate how long the client’s services can be unavailable (and this time is minimal) and take on the problems associated with technical and software failures in the data center.
An accurate roadmap will help you plan your application migration to cloud and avoid critical mistakes. It is important to appoint not only the sequence of actions but also the deadline for completing each task. Critical services are transferred when they are least loaded (for example, at night). Ideally, you want the migration to go seamlessly, and clients of the company’s services will not notice it.
After completing the previous points, you can begin to transfer data, services, and other intangible components of the IT infrastructure. At the final stage, the work of all systems in the cloud environment is tested and fixed in case errors arose during the migration process. It is important to understand whether the service turned out to be really functional.
Enterprise applications move to the cloud is a phased process that is a collaborative effort between the customer and the cloud provider. In most cases, the move is performed not from hardware, but from a working virtualization system, but, despite this, the process requires special preparation.
Analyzing the application migration best practices, we can single out several main stages. Each of them has its own nuances, and knowing these will help you to avoid making mistakes.
- Preparation phase. Preparation begins with an assessment of the existing infrastructure and a migration plan. You need to calculate the exact capacity of the resources that you plan to move to the cloud. Often they may be smaller than what is currently used. Working with your own physical or virtual infrastructure, you build capacity in order to anticipate future growth in business demands, as well as level out optimization flaws that are excluded in a cloud provider environment. Renting a virtual infrastructure allows you to add additional resources only when the need arises, therefore, if you calculated that a certain service requires 2 cores, 16GB of RAM and 500 GB of disk space, then only that much needs to be rented, and when you need to increase performance – adjust the specification.
- Transfer plan. It is necessary to create a table listing all the transferred services, specify the consumed resources for each, determine the transfer priority, and the criticality of the stop at the time of transfer. The usual practice is that first, non-critical services are transferred to the cloud, those on which you can test work with a cloud provider, and only after a while the rest of the infrastructure is migrated.
- Choosing a transfer method. Basically, the applications migration method depends on the source platform (the type of virtualization in the case of a private cloud migration or an iron server) and data activity (will it be an offline move or it is necessary to transfer hot data). The speed of the Internet channel between the source infrastructure and the cloud provider’s data center also plays a role. If the speed or quality of the communication line is low, it makes sense to consider the option of migrating using an external NAS. After the services that will migrate to the cloud have been identified, their power consumption has been calculated, a migration plan has been drawn up taking into account the priority, the data transfer method has been selected and an agreement has been concluded with a cloud provider, you can start moving to the cloud. At this stage, the services are transferred to the provider’s cloud. There are many options for how this can happen, each suitable for a specific infrastructure.