PyParis 2017 http://pyparis.org

1. Coding For Cloud
Harjindersingh Mistry
Bargava Subramanian
Red Hat

2. Grace
● Smart individual
● Just finished MBA
Mark
● A geek
● Just completed engineering

3. Grace & Mark
Online Store

4. Hey Mark,
We don’t have enough money to
buy our own servers !
So, can we rent some ?
That sounds like a good idea, Grace !
That’s called Cloud Computing. I
remember what Prof told about it ...

5. Cloud Computing
● Computers on rent
● Some guy has lot of computer infrastructure
○ He wants to give it on rent to make money
● Very similar to car-rental service like Europcar
● Cloud-native Application is a program that is designed and
developed specifically for cloud computing architecture

6. Alright, I have finished the
implementation !
Cloud, Take it and go !

7. Hey dude, customers are
reporting that our service is very
slow :(
Please check what is wrong
there.
Oh! is it ? But I had used best algo!
Ahha, there seems to be a scalability
issue. Let me call my Prof and get his
suggestions ...

8. Horizontal Scalability
● Think of data in terms of standard ‘collections’
● Write functional as much as possible
● Let the data flow through functions:
○ If data is static then we can do Parallel Processing
○ If data size is not fully known then we can be Reactive
○ There is also a possibility of mixing them together by using Stream
Processing

9. Alright, I have done cool
clustering and my architecture is
reactive now!
Cloud, …. take it and go !

10. Wow Mark, the customers seem
to be happy with performance
now :)
But one customer has reported a
bug ! Can you please fix it ?
Oh! is it ? Let me check that.
It might be something related to
“data-access” module.

11. Ok ! So, I have fixed the
“data-access” module.
Cloud, …. take it and go one
more time !

12. Hey dude, what are your
programming ?!?
There is another bug reported :(
Oh! is it ? Let me check that.

13. Oh man, this debugging is taking
forever :(
I need to configure the whole
system to repro the scenario !
...
Finally, I got it !!!
Bug is inside “business-logic”
module. I fixed it. Let me test the
whole app.
Come on Mark ! How much more
time do you need ?

14. Ok ! So, the tests passed. Cloud, ….
take it and go one more time !
Wait, now I remember what Prof
said about Micro Services ...

15. Micro Services
● Divide the whole application into smaller services, called
Micro Services
● It gives flexibility in testing and deploying in small
independent chunks
● This improves maintainability a lot

16. Ok ! So, I have done Micro
Services :)
Cloud, …. take it and go !

17. Awesome Mark ! We are doing
good !
How about adding one new
feature into our store !
Oh yes ! That will be fun :)
It has been while since I coded
something meaningful !

18. Alright ! The new feature is ready !
But I somehow don’t like all micro
services sharing same computing
resources :(
Let me talk to Prof ...

19. Containers
● Deploy services by using Containers
● Containers increase speed of deployment
● Developer can simulate production environment locally
● Moreover, each service runs in its own environment
○ So if one service goes down, others are still safe

20. So, now I have each micro
service containerized separately
! That looks good.
Cloud, take it and go !

21. Crux of the Story
● Current business model demands speed
○ Need to experiment: It’s ok to fail, but fail fast
○ Need the ability to react: Everything cannot be planned
● But, the software has to be good in terms of:
○ Correctness
○ Performance
○ Maintainability
○ Operability

22. Cloud Native Application
● It helps us experiment with an idea
● We can achieve those attributes of good software as follows:
○ Correctness: Test cases. This cannot change :)
○ Performance: Horizontal Scalability
○ Maintainability: Micro Services
○ Operability: Containers

23. Cloud Native Application: Example
● Movie Recommendation Service
● Cloud Native Machine Learning Application in Python
● There are two parts:
○ Offline Training Job:
○ Online Scoring Service:
Movie Data Training Job ML Model Cloud Storage
User Input + Model Scoring Service Recommendations

24. Layers of Cloud Native Application
Deployment
Output Channel
Functionality
Data Access
S3 Local Files ...

25. Functionality Layer
● Contains core business logic
● As much ‘functional’ as possible i.e. immutability and statelessness
● Data flows through pipeline of functions:
● For example:
Input Data Function-1 ... Function-N Output Result
Input Data Read/Split Transform Train ML Model

26. Data Access Layer
● Provides abstraction on various data sources
● Helps in testing the core logic locally
Abstract Class / Interface
S3 Local Files ...

27. Output Channel Layer
● Different channels for different consumers
● For micro service, it will have REST component
Functionality
CLI REST ...

28. Deployment Layer
● Contains the scripts for deployments
○ Docker files and/or YAML files for containers
○ Python scripts with calls to vendor-specific APIs e.g. AWS API run_job_flow()

29. Demo
● Functionality Layer: Training
● Functionality Layer: Scoring
● Deployment Layer: OpenShift
Input Data Read/Split Transform Train ML Model
User Input + Model Scoring Service Recommendations

30. Not Covered
● Continuous Integration / Continuous Delivery
● Security
● Monitoring
● Vendor APIs for deployment

31. Code, Slides and Contact
● Code:
○ https://github.com/harjinder-hari/cloud_native_analytics
● Slides:
○ https://speakerdeck.com/harjinderhari/coding-for-cloud
● Contact:
○ Harjinder email: harjinder.v2@gmail.com
○ Bargava twitter: @bargava

32. Conclusion
● Current business model demands speed
○ Need to experiment: It’s ok to fail, but fail fast
○ Need the ability to react: Everything cannot be planned
● Cloud Native Applications is a way to achieve it
○ We saw
■ Layers involved in a cloud native application
■ Techniques to achieve the required speed
■ Everything is written in Python ! :)

33. Images Courtesy
[1] Grace and Mark
https://image.freepik.com/free-vector/happy-university-students_23-2147531065.jpg
[2] Professor
https://image.freepik.com/free-vector/science-teacher_23-2147509483.jpg
[3] Rocket
https://image.freepik.com/free-vector/launching-business-concept_23-2147504957.jpg