Minimum Viable Migrations
bene@theodo.co.uk
Ben Ellerby
@EllerbyBen
A Path to Cloud Modernization
Ben Ellerby
@EllerbyBen
serverless-transformation
Structure
🛹 What is Agile & MVP
👷♀️ Cloud Migration and Modernization
☁️ Modern Cloud: Serverless
🚀 Minimum Viable Migrations
📋 Structuring Progressive Migration
👨💻 Team Upskilling
@EllerbyBen
@EllerbyBen
Agile & MVP
🛹
@EllerbyBen
Agile & MVP
What is Agile
In software development, agile practices approach discovering requirements and developing solutions through the collaborative effort of self-organizing and cross-functional teams and their customer(s)/end user(s).
What is Agile
In software development, agile practices approach discovering requirements and developing solutions through the collaborative effort of self-organizing and cross-functional teams and their customer(s)/end user(s).
@EllerbyBen
Does this look like the migration project's you've seen?
- discovering requirements collaborative effort
- cross-functional teams
- customer(s)/end user(s)
@EllerbyBen
What is an MVP?
A minimum viable product (MVP) is a version of a product with just enough features to be usable by early customers who can then provide feedback for future product development.
Learning
@EllerbyBen
BUILD
MEASURE
LEARN
Purpose of MVP
@EllerbyBen
- Test hypotheses early
- Learn faster
- Reduce waste
- Ship to customers quicker
- Validate assumptions
- (and other more brand related advantages)
@EllerbyBen
Cloud Migration
&
Modernization
👷♀️
Cloud Migration
The process of moving digital business assets and operations to a cloud provider / to another cloud provider
@EllerbyBen
Application Migration
The process of moving an application to a different environment
@EllerbyBen
Migration Cloud
- Rehost - "lift-and-shift"
- Refactor - Reuse existing code, but ontop of more abstracted infrastructure
- Rebuild - Re-architecting/writing the application.
- Replace - discard and "buy-not-build" via a SaaS application
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Domain Shift
@EllerbyBen
A
B
APP
APP
Traditional Migration Structure
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On-Prem
APP
APP
Cloud
Language / Framework Migration
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.NET
APP
APP
TypeScript
Structural Migration (Microservices)
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Monolith
APP
Cloud Modernization
@EllerbyBen
Cloud
APP
Cloud Native
Serverless
@EllerbyBen
Serverless
A New Cloud-Native
What is this Serverless thing?
-
Architectural movement
- “allows you to build and run applications and services without thinking about servers” — AWS
- Developers send application code which is run by the cloud provider in isolated containers abstracted from the developer.
- Use 3rd party services used to manage backend logic and state (e.g. Firebase, Cognito)
- A framework with the same name
@EllerbyBen
Why Serverless?
💰 Cost reduction
👷♀️ #NoOps... well LessOps
💻 Developers focus on delivering business value
📈 More scalable
🌳 Greener
@EllerbyBen
Not just Lambda (FaaS)
Lambda
S3
Dynamo
API Gateway
Compute
Storage
Data
API Proxy
Cognito
Auth
SQS
Queue
Step Functions
Workflows
EventBridge
Bus
Power and Flexibility to build...
@EllerbyBen
Serverless Microservices
@EllerbyBen
Microservices work well when:
@EllerbyBen
- Are split into clear Services
- Can be deployed independently
- Only communicate with each other asynchronously
- Master their own data
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Event-Driven Serverless
@EllerbyBen
Side Note: EventBridge Storming
https://medium.com/serverless-transformation/eventbridge-storming-how-to-build-state-of-the-art-event-driven-serverless-architectures-e07270d4dee
@EllerbyBen
Minimum Viable Migrations
Waterfall: As-Is To-Be
@EllerbyBen
As-Is
To-Be
APP
APP
Waterfall: As-Is To-Be
@EllerbyBen
As-Is
To-Be
APP
APP
Requirements
Design
Implementation
Verification
Deadlock of "Feature Parity"
@EllerbyBen
As-Is
To-Be
APP
APP
| SSO | 1 | 0 |
| CRM Integration | 1 | 0 |
| Email Sending | 1 | 0 |
| Core Feature X | 1 | 1 |
| Legacy Feature Y | 1 | 0 |
| ... | 1 | 0 |
Deadlock of Parity
@EllerbyBen
As-Is
To-Be
APP
APP
| SSO | 1 | 1 |
| CRM Integration | 1 | 1 |
| Email Sending | 1 | 1 |
| Core Feature X | 1 | 1 |
| Legacy Feature Y | 1 | 1 |
| ... | 1 | 1 |
How to achieve odd parity
@EllerbyBen
As-Is
To-Be
APP
APP
| SSO | 1 | 1 |
| CRM Integration | 1 | 1 |
| Email Sending | 1 | 1 |
| Core Feature X | 1 | 1 |
| Legacy Feature Y | 1 | 0 |
| ... | 1 | 1 |
Least significant "bit"/feature
How to achieve odd parity
@EllerbyBen
How do we release a version of the system without a low priority feature
- Run an opt-in beta program?
- Remove high cost - low reward features?
- Move users who don't need the feature
How to achieve odd parity
@EllerbyBen
How do we release a version of the system without a required high priority feature?
- We need a strategy to run 2+ systems in parallel with a clean interface/contract that does not negatively impact the design of the new system with the constraints of the old.
- An exit strategy from the old system to eliminate the complexity and risk of running parallel systems
Minimum Viable Migrations (MVM)
@EllerbyBen
A Minimum Viable Migration (MVM) is a usable migrated version of an application from one domain/paradigm to another with a subset features to be used by some or all customers
Minimum Viable Migrations (MVM)
@EllerbyBen
Why?
- Learn faster
- Test assumptions earlier
- Focus the team and create a culture of continuous deployment
- Deliver value to customers faster
Features: As-Is To-Be
@EllerbyBen
As-Is
To-Be
APP
APP
Waterfall: As-Is To-Be
@EllerbyBen
As-Is
To-Be
APP
APP
Model the new system in terms of Events
@EllerbyBen
- Event-Driven architectures are becoming the default for modern Cloud-Native Applications.
- We need to design the architecture of the system "to-be" in terms of events.
@EllerbyBen
EventBridge Storming
@EllerbyBen
Event Schema
- Teams should be able to work on and deploy Services independently.
- Teams need to agree on the structure of Events, their Schema.
- Title, structure and types.
- Teams should share Schema, not data and code.
Let's rethink...
@EllerbyBen
As-Is
To-Be
APP
APP
MVMs: Progressive Migrations
@EllerbyBen
As-Is
To-Be
MVM
MVM
MVM
MVM
MVMs: Progressive Migrations
@EllerbyBen
To-Be
MVMs: Progressive Migrations
@EllerbyBen
As-Is
To-Be
Events are the contract
@EllerbyBen
- Event Schema of the new system is the contract between the system.
- Not a web of tightly coupled synchronous request response integrations.
MVMs: Progressive Migrations
@EllerbyBen
Requirements:
- Defined list of events and schema from the business domain.
- Event Bus in the new system
- Ability to emit events from the old system
- Ability to react to events from the new system
MVMs: Progressive Migrations
@EllerbyBen
-
Advantages
- Go live faster
- Iteratively build up feature parity
- Learn faster
- Test Assumptions faster
- The "new system team", who may not be experts in the prior tech can work independently, with other teams doing the integration work to emit events from the Legacy
MVMs: Progressive Migrations
@EllerbyBen
-
Challenges
- Managing data duplication
- GDPR
- Networking between systems (on-prem <> Cloud Hybrid?)
- Finding event trigger mechanisms in the old system
@EllerbyBen
Team Upskilling
👨💻
Bring people along the journey
@EllerbyBen
- Leverage expert knowledge to map out initial architecture for a MVM (Minimal Viable Migration)
- Embed experts (internal, contractor, consultant, AWS SA…) in the team to build the initial MVP/MVM with your existing people.
- Provide the structure, time and resources for the team to develop an autonomous capability to deliver.
Providing a Structure:
Skills Matrix
@EllerbyBen
- List the knowledge areas highlighted for the MVM
Format this in a “Skills Matrix" - Review the individual and group scores on a weekly basis
- Pro Tip: Target pair programming from gaps in the skills matrix
Providing a Structure:
Skills Matrix
@EllerbyBen
Measure progress across sprints and MVMs
@EllerbyBen
Conclusion
@EllerbyBen
- MVMs allow you to release, test assumptions, learn and deliver value faster
- MVMs are iterative stepping stones to the to-be "final system"
- An Event-Driven architecture allows a clean bi-directional interface between systems.
- Bring your people on the journey by empowering them with the tools, resources and learning paths
Spoiler Alert:
There is no final "to-be" for any system
@EllerbyBen
MVM
MVM
MVM
MVM
MVM
You keep iterating on your MVM
@EllerbyBen
serverless-transformation