SpringOne Platform 2018 Re-Platforming Legacy .Net Applications to PCF Using Modernized Techniques Poornima Varadhan, Cognizant; Alfus Jagnathan, Pivotal

1. Replatforming Legacy .NET Applications
to PCF Using modernized (Steeltoe)
techniques
Alfus Inigo Jaganathan
Advisory Solutions Architect
Pivotal
Poornima Varadhan
Global Engagement Lead
Cognizant
By -

2. Unless otherwise indicated, these slides are © 2013-2018 Pivotal Software, Inc. and licensed under a Creative Commons
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Disclaimer

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Agenda

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What to expect in the next 30 mins?
• Quick introduction to PCF & Steeltoe
• Understanding 15 Factors, run through the relevant ones for this talk
• Migration Patterns, a high level overview
• Replatforming in detail with code snippets
• Demo the Replatformed .NET Webform app to PCF
• Pivotal AppTx and Tools
• Partner talk on "Partner & Accelerate to operate at scale” - Cognizant

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Pivotal Cloud Foundry

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PCF – A modern cloud native platform
• Supports multi-languages -
buildpacks
• Supports Hybrid Cloud (On-Prem
& public)
• Supports Multi Cloud (IaaS –
Azure, AWS, GCP, etc.) -
Portability
• 4 Levels of HA
• Zero downtime deployment
support
• Elastic scalability
• Developer focus on delivering
business value
• Reduce Operations/DevOps cost

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Steeltoe.io

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Steeltoe.io for .NET developers
9
• Open source
• Industry standard best practices building microservices
• Available as .NET Standard NuGet libraries
• Supports .NET Core and Full Framework
• Helps leveraging
• Netflix Eureka (Service Discovery)
• Hystrix (Circuit Breaker)
• Spring Cloud Config Server
• Cloud Connectors
• Cloud Security Providers
• Monitoring and Management
• What's new in 2.1
• Additional Spring boot compatible endpoints
• Out-of-the-box Health contributors
• Application Metrics
• Distributed Tracing
• Additional .NET 4.x support

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15 Factors

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15 FACTOR PCF Steeltoe
1
One codebase,
one application
• Single codebase
• Any number of immutable releases
N/A N/A
2 API first
• Contract first development
• Server mocks (e.g. Apiary)
N/A N/A
3
Dependency
management
• Isolate dependencies as NuGet packages
• Bundle dependencies together with build artifacts
• Self Contained
• Buildpacks N/A
4
Design, build,
release, and run
• CI/CD Pipeline
• Iterative
• Zero downtime
• Integration with Concourse,
Jenkins, etc.
• Blue-Green & Canary deploy
N/A
5
Configuration,
credentials, and
code
• Code - Single artifact for multi environment
• Externalize configuration and credentials
• Treat configuration as ENV variables
• ENV variables
• User Provided Services
• Structured ENV variables from
bounded services
• Config Server (Git & Vault)
• .NET
Configuration
Extensions NuGet
packages
Understanding 15 Factors (Ref: https://content.pivotal.io/blog/beyond-the-twelve-factor-app)

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15 FACTOR PCF Steeltoe
6 Logs
• Treat as event streams
• Sequence of time-ordered emitted events
• STDOUT and STDERR
• Loggregator-Firehose (cf logs)
• CF Syslog Drain – stream to external
aggregation/analytics service
• Apps Manager
• Dynamic Logging
• Management – Actuators
(Integration with Apps
Manager)
7 Disposability
• Maximize Robustness
• Fast startup & Graceful shutdown
• Externalize using backing services (e.g. Cache)
• High Availability (Health
Management of App Instances)
• Maintain capacity
• Management – Health
Contributors
8
Backing
Services
• Treat as attached resources.
• Loose coupling, flexibility
• E.g. data store, caching, etc.
• Market Place services (Redis, Rabbit,
MySql, etc.)
• Circuit Breaker as MP service
• Open Service Brokers
• cf bind-service, cf unbind-service
• Implementation of Netflix
Hystrix (Circuit breaker,
Netflix Eureka (Service
Discovery)
• Connectors
9
Environment
Parity
• Keep all environments including development
as similar as possible
• Application “will work everywhere”
• Every commit, a deployment candidate
• PCF Dev
• Similar experience to developers
• Logical separation called ‘Spaces’,
on single foundation
N/A
10
Administrative
Processes
• Run admin/management tasks as one-off,
scheduled processes • CF Tasks and Task scheduler N/A
Understanding 15 Factors (Ref: https://content.pivotal.io/blog/beyond-the-twelve-factor-app)

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15 FACTOR PCF Steeltoe
11 Port Binding
• Avoid micromanaging port assignments
• Allow externalized runtime port binding
• 1 : 1 (App instance : App
Server)
• PCF GoRouter routes to App
instances
N/A
12
Stateless
Processes
• All long-lasting state to be externalized using
backing services (e.g. session)
• Share-Nothing (containers are highly disposable)
• Externalize data caching
• MP services like Gemfire,
Redis, etc.
• File System as service
• Connectors as NuGet
packages
• Seamless integration
with backing services
13 Concurrency
• Scale out horizontally rather than vertical scaling
• Should be able to run multiple concurrent instances
• Elastic scaling made easy
• Auto scaler (scale by demand
automatically)
• cf scale
N/A
14 Telemetry
• Application Performance Monitoring(APM) –
Wellness
• Domain specific telemetry– Analytics & Reporting
• Health & System logs – Stream of events
• PCF Metrics
• cf events & cf logs
• Syslog Drains and Nozzles
• Management/Actuators
• Apps Manager
15
Authentication
& Authorization
• Security should be never be an after thought
• Should be backed in from day one
• UAA Server
• Pivotal Single Sign-on
• CredHub
• Platform provided security,
firewalls, etc.
• Security provider
packages for seamless
integration with security
providers
Understanding 15 Factors (Ref: https://content.pivotal.io/blog/beyond-the-twelve-factor-app)

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Migration Patterns

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Migration Patterns
15
• Replatforming to start
with…
• Start small
• Less cost involved
• Faster time to value
• In longer term, based on
business value/criticality
of the app, move towards
modernization

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Replatforming

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Replatforming
17
• Minimal Efforts
• Less cost
• Sometimes called Lift & Shift
• Run natively in PAS (Pivotal Application
Service)
• Cloud Ready/Friendly
• Critical 12/15 factors
• Configuration, Credentials & Code
• Logs
• Stateless Processes
• Concurrency
• Dependency Management
• Port binding
• Authentication & Authorization
• One Codebase One Application*
• Build, Release and Run*
* Recommended, but not critical

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.NET Apps – PCF Readiness
18
• High level .NET to PCF
• 4 categories
• *Out of scope includes
• Apps being retired within
6-12 months
• Vendor/3rd party apps
• Databases
• Reporting/BI Front end
apps

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Replatforming (Steps)
19
• Create and move to a separate repository (15F - One Codebase One
Application)
• Upgrade to latest .NET framework preferably 4.6.1 or above
• Helps leveraging .NET Standard libraries like Steeltoe.io
• Build CI-CD pipeline (15F – Design, Build, Release and Run)
• Bring all the dependencies (Registry, GAC, 3rd party) to Bin, with the
publish artifacts (15F – Dependency Management)

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Replatforming (Steps)
20
• Remove any code that micromanages the port, let the platform take
care of port binding (15F – Port Binding)
• Verify if application access any File system. In that case, modify the
code to access either s3 object storages or NoSQL database or Pivotal
volume services. (15F – Disposability)
• Make use of Steeltoe.io libraries and other techniques (following
slides) to implement remaining of critical factors one by one

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Leveraging Steeltoe.io
21
• Prerequisite: framework must be updated to 4.6.1 or above
• 3 types of packages (Samples https://github.com/SteeltoeOSS/Samples)
• Autofac - Autofac dependency injection (e.g. Steeltoe.Extensions.Configuration.CloudFoundryAutofac)
• Base - No dependency injection (e.g. Steeltoe.Extensions.Configuration.CloudFoundryBase)
• Core - ASP.NET Core dependency injection (e.g. Steeltoe.Extensions.Configuration.CloudFoundryCore)
• Here we use Core package for the demo and sample, with a simple
technique using Generic Host Builder
• Add appSettings.json, to have a .NET Core kind of…

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Leveraging Steeltoe using Generic Host Builder
22
• CoreServiceConfig.cs under App_Start
• Packages used
o Microsoft.AspNetCore.Hosting
o Microsoft.Extensions.DependencyInjection
o Microsoft.Extensions.Logging
• CoreServiceConfig.Register() from
Global.ascx.cs, entry point of the
application
Ask the container for injected services from
anywhere in the application

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Configuration (15F - Configuration, Credentials and Code)
23
• Packages
o Steeltoe.Extensions.Configuration.CloudFoundryCore
(User-Provided-Services & Bounded Services)
o Pivotal.Extensions. Configuration.ConfigServerBase
(Config Server)
• Config Server backed by vault and git (vault for
secrets and credentials & git for non-sensitive
configuration
o Recipe ref: https://dotnet-cookbook.cfapps.io/config/config-
server-vault-git-dotnet-core/
• Bounded services
configuration and User-
Provided services can be
pulled via
• Structured ENV variable
• CloudFoundryServicesOptions, a
JSON representation of
VCAP_SERVICES configuration

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Configuration (15F - Configuration, Credentials and Code)
As an example, Connect to SQL Server using Steeltoe connector
24
• Package(s)
Steeltoe.CloudFoundry.ConnectorCore
• This includes base and almost all connectors.
Alternatively you can use specific connector packages
like Steeltoe.CloudFoundry.Connector.SqlServer

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Externalize Session (15F – Backing Services & 15F – Concurrency)
As an example, Redis as the persistent store
25
Additional reference: https://dotnet-cookbook.cfapps.io/aspnet/redis-
session-full-framework/

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Externalize Caching (15F – Backing Services & 15F – Concurrency)
As an example, Connect to Redis using Steeltoe connector
26

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Logging (15F – Logs)
27
• STDOUT/STDERR
• Simply write à
Console.{Out/Error}.WriteLine(“Something…”);
• If using 3r party like log4net, Nlog, etc., modify
their Appender config to type “Console”
• Replace with Microsoft.Extensions.Logging
Ilogger, but a bit more of a work
• Enhance using Steeltoe’s dynamic logging
feature, lets you change the log levels without
restarting the application (next slide)
Ref: https://steeltoe.io/docs/steeltoe-logging/

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Enable Steeltoe Management Actuators
Health Contributors, Dynamic Logging and much more… (https://steeltoe.io/docs/steeltoe-management/)
28
In Global.ascx, call out as below to activate
the actuators
appSettings.json should
have this configuration

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Security (15F – Authentication and Authorization)
29
• Straight forward, if using Forms Authentication
• Windows Authentication
• Not-supported, so use Pivotal Single Sign-on or UAA or similar Identity providers
• Leverage Steeltoe middleware and OWIN request pipeline to integrate with any identity
provider supporting OAuth & OpenID Connect
• Package Steeltoe.Security.Authentication.CloudFoundryOwin
• Ref: https://steeltoe.io/docs/steeltoe-security/ & https://github.com/SteeltoeOSS/Samples/tree/dev/Security
• Optionally, you can create your own HttpModule which can intercept on
HttpContext.AuthenticateRequest, set httpApplication.Context.User from newly generated
GenericPrincipal using JWT, etc.

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.NET Apps - Buildpacks
30
• Buildpacks-
• Provides framework and
runtime support
• Determines, what
dependencies to download
• Configures the apps so as to
communicate with bound
services
Learn more about buildpacks? https://pivotal.io/platform/pcf-components/buildpacks

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Demo – Replatformed App (with
Steeltoe Actuators) in PCF
Recording link https://1drv.ms/v/s!AhnjuwdpuapykJI7M_KFmmgwlezG7A

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Pivotal AppTx & Tools

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Pivotal Application Transformation Team (AppTx)
https://pivotal.io/application-transformation
33
Who we are?
ü Team of Solutions Architects and
Strategists
ü Jump start App Tx to quickly show
measured wins
ü Simple tools, Start small & Scale fast
ü Redefine current systems to achieve cloud
native speed, resiliency and economics
What we believe?
ü Should move Apps to PCF
ü Plan just enough to start
ü Define hard goals and measure them
ü Automate everything you can
ü Build skills by pairing and doing
ü Let real work inform strategy

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Pivotal Tools (Get Started, Measure Incremental, Learn as You Do)
https://www.youtube.com/watch?v=neL3OQ1GRhY
34

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Partner Talk
https://www.cognizant.com/cognizant-digital-business/digital-engineering-services

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Partner & Accelerate to operate at scale
• Deeper domain knowledge
• Deeper services knowledge
• Application expertise/ Digital Engineering skills
36
+
enabling clients to accelerate their digital transformation journey with rapid application
portfolio migration and cloud-native development at scale.
• Market leading s/w development methodology
• Technology & Tool offerings
• Cloud Native Innovation
• App Tx & Labs

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Scale better yet be more sustainable - How we do it?
PEOPLE
• Talent pool of 1/5 of workforce skilled as engineers and Full Stack developers.
• Put the right work in the right place at the right cost for scale
o Working with customers on premise alongside with Pivotal as needed
o Leveraging Cognizant Labs
o Operating in On/off model as appropriate.
• Training - PAL , T skilled
PROCESS
• Adoption of Product-engineering principles to build or modernize S/W -(Lean Engineering , XP , Build
test and learn methodologies etc.)
TECHNOLOGY
• Empower Engineering and Product Development teams with Tools and accelerators (like VSM) to
automate the tasks / processes. - VSM : Evaluates application code to identify changes needed (like
antipatterns etc.) to help determine the type of remediation needed.

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Driving change & adoption - Top Challenges
38
• Inadequately equipped from a skill, culture, mindset, inclination, and talent perspective -
Increasing education, skill building, and drive culture change
• Top-down communication is a gap in ensuring teams are aware, coordinated, & are able to
actively support digital change efforts at each level of the organization - Addressing missed
leadership communications opportunities
• Buy-in with Stake-holders for adoption of newer application delivery model - discussing
adequately with Business / IT customer teams on the need for right agile practices for right
work
• Operating with the old measures , metrics & governance – stressing the importance to
Redefine / Revamp the tools , processes , automation & metrics

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In summary, transformation journey’s continued success is on…
• How quickly enterprise embrace change , drive culture shift and be agile
• Learning & Sharing among Digital leaders
• How to do it @scale repeatably and sustainably.
Jeff Bezos - Amazon Founder
In today's era of Volatility , there is no other way but to re-invent ,
the only sustainable advantage you can have over others is AGILITY ,
that's it. Because nothing else is sustainable , everything else you create ,
somebody else will replicate

40. @poornima_30
#poornima-varadhan
poornima.Varadhan@cognizant.com
Thank you! Stay Connected!
#springone@s1p
@alfusinigoj
#alfusinigojaganathan
ajaganathan@pivotal.io