Chapter 2. Migrating into a Cloud

Chapter 2.

Chapter 2.

Migrating into a Cloud

Migrating into a Cloud

(a)

(a)

Introduction

Introduction

- 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:

# 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)

(b)

Broad approaches to migrating into the cloud

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?

# 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

→ 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, Mi, i = 1..M

- Class Mi has Ni questions

- Each class is assigned a certain relative weight Bi, i = 1..M

# The decision making can be modeled as an M×N weight matrix:

C_l ≤

∑

(

∑

)

- Ch: higher weight threshold

- Xij : the degree to which that answer to the question is relevant and applicable, 0 ≤ Xij ≤ 1

(c)

(c) The seven-step model of migration into a cloud

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

* 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

- 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