Chapter 2. Migrating into a Cloud

Transcription

1 (a) Introduction Chapter 2. Migrating into a Cloud - Cloud computing: a disruptive model of IT * Part technology and part business model * Raised the IT expectations of small and medium enterprises * Large companies are deeply debating it * Questions: # When and how to migrate one s application into a cloud? # What part or component of the IT application to migrate into a cloud and what not to migrate into a cloud # What kind of customers really benefit from migrating their IT into the cloud - Promise of cloud computing services * Cloudonomics: # Pay per use: lower cost barrier # On demand resources: autoscaling # CAPEX vs OPEX: no capital expenses (CAPEX) and only operational expenses (OPEX) # SLA driven operations: much lower TCO (Total cost of ownership) # Attractive NFR (Not-for-resale) support: availability, reliability * Technology: 2-1

2 # Infinite elastic availability: compute/storage/bandwidth # Automatic usage monitoring and metering # Jobs/tasks virtualized and transparently movable # Integration and interoperability support for hybrid operations # Transparently encapsulated and abstracted IT features - Features of cloud services * Typically web-oriented * Represents seasonal IT demands * Non-mission critical * Low demand of security (b) Broad approaches to migrating into the cloud - Migrating to cloud is a trend * Top 10 strategies to watch for 2013 * Questions: # Cost to migrate to cloud appropriate? - Capital expense eliminated, operational expenses incurred only # Total cost of ownership of data reduced? - Keep data on cloud provider s or the company s data center - Why migrate? * Ways of migration: 2-2

3 # An independent application on the cloud # Code of the application needs to be modified to be on the cloud # The application needs to be redesigned # The architecture of the application needs to be redeveloped # The application stays as it is, but the usage needs to be changed * In summary: # Migration can happen in one of the five levels: application, code, design, architecture, and usage # Representation of the migration of the enterprise application: P P' C + P' l P' OFC + P' l - P: application before migration - P' C : part of the application migrated into the cloud - P' l : part of the application staying local - P' OFC : the application part optimized for cloud - If the entire application is migrated, P' l : is null * Cost-effective analysis: analyze the migration representation of the application, e.g.: # IaaS migration: 30 use-case scenarios # PaaS migration: 20 use-case scenarios # SaaS migration: only usage What s the total cost? * Cloudonomics 2-3

4 Cost cutting in CAPES and OPEX # Cost of migration: is it economically feasible or tenable? # License fee: SLA compliance # Price of the cloud offerings - Deciding on the cloud migration * Design a questionnaire with several classes of key questions that impact the IT due to the migration * Pose the questionnaire to selected people (technical and business experts) * Modeling the decision making: # Suppose: - There are M classes of questions, M i, i = 1..M - Class M i has N i questions - Each class is assigned a certain relative weight B i, i = 1..M # The decision making can be modeled as an M N weight matrix: M C l i=1 N i B i( j=1 A ij X ij) C h - E.g., B 1 (A 11 X 11 +A 12 X 12 + ) + B 2 (A 21 X 21 +A 22 X 22 +A 23 X 23 + ) + - C l : lower weight threshold - C h : higher weight threshold - A ij : a constant assigned for a question 2-4

5 - X ij : the degree to which that answer to the question is relevant and applicable, 0 X ij 1 (c) The seven-step model of migration into a cloud - Seven-step model of migration * Conduct cloud migration assessment # Understand the migration issues at the application level or the code, the design, the architecture, or usage levels # Cost of migration: ROI (Return of investment), TCO, * Isolate the dependencies # Isolate all systematic and environmental dependencies of the enterprise application components within the captive data center * Map the messaging and environment # Message map: displaying detailed, hierarchically organized responses to anticipated questions or concerns # Generate the mapping constructs between what shall remain in the local captive data center and what goes onto the cloud * Re-architect and implement the lost functionalities # Perhaps some functionality may be lost due to migration # Some part of the enterprise application may need to be re-architect, redesigned, and reimplemented on the cloud 2-5

6 * Leverage cloud function and features # Leverage the intrinsic features of the cloud computing service to augment the enterprise application * Test the migration # Test the new form of the enterprise application (both on the captive data center and on the cloud as well) * Iterate and optimize # Iterate and optimize the process - Migration risks and mitigation * In the seven-step model: # Test step: identify the key migration risks # Optimization step: mitigate the migration risks * Two categories of risk: # General migration risks - Performance monitoring and tuning - Business continuity and disaster recovery of the cloud computing service - Compliance with standards and governance issues - Licensing issues 2-6

7 - QoS parameters and SLA - Ownership, transfer, and storage of data in the application - Portability and interoperability issues that would mitigate potential vendor lock-ins # Security-related migration risks - Trust and privacy - The right to obtain execution logs and audit trails as a detailed level - Problems due to multi-tenancy - Data leakage 2-7