Help Center/ Cloud Adoption Framework / Cloud Adoption Framework and Practices/ Adoption Implementation/ Application Cloud Migration/ Cutover/ Mock Cutover
Updated on 2025-05-07 GMT+08:00
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Mock Cutover

Once the function and performance tests are completed, and the cloud applications and services run properly, the service cutover can be initiated.

Service cutover is the process of transitioning service operations from the source legacy system to the new cloud platform. It requires meticulous planning and coordination to ensure data integrity and service stability during the cutover.

In most cases, service cutover takes a certain period of time. In this period, requests are redirected to the cloud platform and the legacy service system will be phased out. This process helps achieve a smooth transition between the old system and the new system, and finally migrate services to the cloud. Therefore, it is common to conduct a mock cutover before real cutover.

Why Is Mock Cutover Needed?

A mock cutover is critical to cloud migration. It can boost confidence and assurance for the real cutover. To be specific, it mainly has the following benefits:

  1. Identifying issues and risks: The mock cutover helps uncover, prevent, and resolve problems, such as an incorrect startup/shutdown sequence of applications and batch tasks, network configuration issues, and data inconsistency issues.
  2. Enhancing team cooperation: The mock cutover enables technical team members to get familiar with the entire cutover process and steps so that they can work together more efficiently.
  3. Optimizing the runbook: The mock cutover helps find out problems in the cutover workflow, such as the overall serial/parallel sequence errors and the execution timeout for certain steps. Thus, the team can refine the runbook steps and timelines to improve the accuracy and feasibility for the real cutover while boosting efficiency.
  4. Estimating the cutover duration: The mock cutover allows the team to know the start time, end time, and execution duration of each step. This enables them to precisely forecast the total duration of the real cutover. Then they can better schedule the service downtime announcement and coordination with other supporting teams.
  5. Minimizing downtime: A large-scale system cutover often involves more than 200 steps, requiring parallel and serial operations and collaboration among multiple roles and personnel. The Mock cutover can improve the team's familiarity with cutover operations, coordination between parties, and problem-solving efficiency. For steps that take a long time, automatic scripts can be used to replace manual operations or further script optimization can be conducted to reduce the downtime caused by the cutover. For example, a solution where all service systems are cut over at a time was adopted for the cloud migration of a large retail platform. After four mock cutovers, the cutover time was shortened by 40%.
    Figure 1 Cutover results
  6. Identifying unforeseen problems: The mock cutover environment can help reveal hidden problems. For example, during a cutover, despite all applications involved in a system being shut down, some database sessions remain active and the data cannot be static. It is found that a third-party store still performs some operations after system shutdown. Such findings allow enterprises to adjust and optimize the cutover plan to ensure a successful real cutover.

Mock Cutover Process

It is recommended that two or three mock cutovers be performed before the real cutover. The mock cutover process is as follows:

Figure 2 Mock cutover process
  1. Cutover preparations

    The preparations for a mock cutover include the following aspects:

  1. Venue/Meeting room: Determine the cutover location (floor) and book a meeting room in advance.
  2. Personnel and role responsibilities: Clearly define the roles and responsibilities of all participants. Ensure that mock cutover participants and the real cutover operators are consistent. Roles can be defined based on the runbook roles in Designing a Runbook.
  3. Runbook preparation: Refine the mock cutover runbook based on the cutover environment. It is best to conduct multiple rounds of review before finalizing the runbook.
  4. Environment preparation: Prepare the source environment and target environment for the cutover. The source environment should mirror the production environment as closely as possible, including data consistency. It is recommended to preconfigure data and check the environment in advance, along with other preparatory steps.

    There are two solutions for preparing the cutover environment. Enterprises can select one of them based on their actual situations.

    1. If no test environment that is similar to the production environment is available in enterprises, deploy both the complete source and target environments on Huawei Cloud for the mock cutover.
      Figure 3 Cutover environment
    2. If a test or pre-production environment is available for use as the source environment in enterprises, deploy only the target environment on Huawei Cloud. The production environment on Huawei Cloud may be reused as the target environment. In this case, strict isolation measures must be implemented to prevent the mock cutover from affecting the live production system.
      Figure 4 Cutover environment
  1. Cutover implementation & review
  • The mock cutover is performed as follows:
    1. The facilitator announces the cutover disciplines and precautions.
    2. The facilitator introduces the tasks, operators, and confirmers according to the runbook. (Note: Multiple tasks may be executed concurrently.)
    3. The operators perform the assigned tasks according to the runbook.
    4. The confirmers conduct a double check after the operators have completed their tasks.
    5. Once confirmed, the confirmers immediately report the result to the facilitator. (Note: For steps involving multiple confirmers, each confirmer should update their completion status in the online shared document for real-time progress tracking).
    6. Repeat the above steps until all tasks are completed.
    7. Operators and confirmers record the issues encountered during the mock cutover for a review.
  • The cutover review is performed in the following procedure:
    1. Classify the recorded technical and organizational issues.
    2. Review each issue, analyze the root cause, and discuss improvement measures.
    3. Assign improvement measures to responsible parties and update the measures to the runbook for next mock cutover or real cutover.
Parent topic: Cutover