My slides from the London Cloud Native Meetup on 7th August 2018. Covering serverless, FaaS (Functions-as-a-Service) and the Fn project (with a bit of help from William Shakespeare).

1. FaaS You Like It
(If Shakespeare had written
Functions as a Service)

2. “All the world’s a stage, And all the men and women
merely players; They have their exits and their entrances,
And one man in his time plays many parts…”

3. Cast
Cloud Architect - Ewan Slater

4. Agenda
1. What is FaaS (or “Serverless”)
2. The Fn Project
3. FDKs
4. As you like it - performed by Fn functions, written in Ruby & Java

5. Synopsis
“As You Like It subverts the traditional rules of romance.
Gender roles, nature and politics are confused in a play that
reflects on how bewildering yet utterly pleasurable life can
be.”
- Royal Shakespeare Company

6. Bewilderment:
Why dost thy Serverless Architecture have
so many servers?

8. Soliloquy
<Grumpy-Old-Man-Moment>

9. There are only two hard things in Computer
Science: cache invalidation and naming
things.
- Phil Karlton

10. I don’t like “Serverless” as a name
● Hidden Servers
● Transient Servers
● Abstracted Infrastructure
● Anything really

11. "For everyone's sake, someone
please come up with a better
name than serverless”
- Simon Wardley

12. </Grumpy-Old-Man-Moment>

13. Suspension of Disbelief

14. “The Play’s the thing…”

15. Actor learns own part
● Cues (input)
● Lines (output)
● Stage Directions (state)

16. Actor ⇒ Function

17. Single responsibility

18. Audience care about action

19. Not what happens backstage

20. Business doesn’t care about
infrastructure

21. FaaS: action not infrastructure

22. Increase developer
Productivity
by adding another layer of
Abstraction

23. (a recurring theme)

24. FaaS
● Write small functions
● Do one thing well
● Easy to Understand
● Easy to Maintain
● Run on Abstracted Infrastructure (“Serverless”) platform

25. Avoid

26. What is “Serverless”?
● Serverless is an abstraction of infrastructure and its operations including
provisioning, scaling, patching, etc.
● Serverless architecture is when an app is built entirely on serverless
components (compute, storage, networking)
● Function as a Service (FaaS) is the compute component in a serverless
architecture

27. For a fuller discussion...
Mike Roberts article on MartinFowler.com
https://martinfowler.com/articles/serverless.html
“Fundamentally, FaaS is about running backend code without managing
your own server systems or your own long-lived server applications.”

28. From Microservices to Functions

29. Granularity

30. Scale

31. Time

32. PaaS vs FaaS
● Granularity, Scale & Time
○ Paas (or IaaS) ⇒ (Micro)Service, long - running
○ FaaS ⇒ Function, invoked on demand
If your PaaS can efficiently start instances in 20ms that run for half a
second, then call it serverless.
- Adrian Cockcroft

33. Functions != Functional
● Functions can have side effects
● Functions don’t have to be idempotent

34. FaaS Upsides
● Make development easier
● Improve developer productivity
● Increased agility (Dev & Business)
● Reduce costs (Dev & Operations)

35. FaaS Downsides
● “ball of mud”
● Lock - in
● Restricted choice
○ Language
○ Run - time environment

36. Language Support
● AWS
○ Node, Python, Java, C#, Go
● Google
○ Node
● Azure
○ C#, JavaScript, F#, (Java - preview)

37. “Gadzooks! No Ruby?”

38. (Or Erlang, or Rust, or FORTRAN etc.)

39. Choice:
Write your functions in any language.
Run them in any environment.

40. Fn Project:
Write your functions in any language*.
Run them in any environment*.
*Supports / supported by Docker

41. Fn Project ( fnproject.io )
● Open-source serverless compute platform
● Can be deployed to any cloud or on-premises
● Containers are primitives
● Active w/ 2500+ commits across 50+ contributors
● Independently governed with representation at CNCF
● support for the upcoming CloudEvents specification
○ (CNCF Serverless working group )
● integration with the Serverless Framework toolkit

42. Functions as Containers
● Function and dependencies
● Single - purpose
● Self - Contained
● Stateless
● Ephemeral
● Run on Demand

43. An Fn Function
● Small chunk of code wrapped into container
● Input from STDIN & Environment
● Output to STDOUT
● Logs to STDERR

52. Fn deploy details
● Bump version in func.yaml
● Build container (multi stage)
● Push container to registry
● Create / Update function route
MyFunc:0.0.2
MyFunc:0.0.2 MyFunc:0.0.2
Your code
Fn Service
myfunc →
/r/myapp/myfunc:0.0.2
1 2 3

54. Fn Server
● “API Gateway”
● Manages apps and functions
○ (app ⇒ group of functions)
● Synchronous function calls
○ Executed immediately
● Asynchronous function calls
○ Queued and executed when capacity available
● Runs as a Container
● Hosts function containers using Docker - in - Docker

55. Docker in Docker
● Limited “blast radius”
○ Doesn’t affect outer VM
○ Kill Fn container & restart
● Docker version independence
○ (inner can differ from outer)
● Reduce chance of container name collisions

56. Architecture

57. Hot and Cold
● Cold Functions
○ Run once only
○ Terminate immediately
○ New container every invocation
● Hot Functions
○ Run at least once
○ Wait before terminating
○ Potentially reusable

58. Synchronous Request

59. Asynchronous Request

60. Function Development Kits (FDKs)
● Developer writes a handler function to the FDKs interface
● FDK
○ Parses STDIN
○ Provides input data to function
○ Handles writing output and errors
○ Manages multiple invocations
● Makes it a lot easier to write hot functions

61. FDKs
● Ruby ( https://github.com/fnproject/fdk-ruby )
● Others
○ Python
○ Go
○ Java
○ Node
○ Rust
○ ...more on the way...

62. Without an FDK
● Dockerfile
● func.yaml
● func.* (e.g. func.sh)
● DIY

64. Orchestration

65. Flow
● Promises based Orchestration
○ No new “special” language
○ Composable
○ Flexible
○ Supports “Saga Pattern”
● A Flow is...
○ ...written in Code
○ ...written as Function
○ ...deployed as a function (within an application)

66. Flow
● Language Support:
○ Java
○ Python
○ Node
● In the works:
○ Go
● To - do:
○ Ruby

67. As You Like It
bitbucket.org/ewan_slater/comedy/src/master/

68. Summary
● FaaS ⇒ Greater developer productivity
● Fn Project ⇒ FaaS Framework
○ Open Source
○ Portable
○ Language Agnostic
○ Multiple FDKs
● Feedback and contributions welcome!

69. Links & Contact
● Fn Project ( fnproject.io )
○ github.com/fnproject
○ Slack
● Twitter
○ Fn Project: @fnproj
○ Me: @ewanslater

70. Proceed, proceed: we will begin these rites,
As we do trust they'll end, in true delights.
(all exit to the pub)