This document provides an introduction to Functions-as-a-Service (FaaS), highlighting its evolution from physical machines to cloud services and the advantages of using stateless functions. It discusses major FaaS providers, trade-offs, state retention challenges, and the benefits of serverless computing, including easier scaling and cost efficiency. The author concludes with recommendations on FaaS platforms, particularly favoring Azure Functions over AWS Lambda and IBM Cloud.

1. A Gentle Introduction to
Functions-as-a-Service
Valeri Karpov
@code_barbarian
github.com/vkarpov15

2. About Me
● Backend Lead @ Booster, Node.js OSS
● Core contributor for Mongoose, Mocha
● Blogger, thecodebarbarian.com
● Early employee at LevelUp, MongoDB, Booster
● Invented the MEAN stack

3. What’s This Talk About?
● The progression of dev-ops for startups
● Why FaaS is the next natural step for dev-ops
● Retaining state in “stateless” functions
● Trade-offs between different FaaS providers

4. 2008: Physical Machine in Dorm Room
● EC2 was limited, other hosting services sucked
● LevelUp’s first release on an Ubuntu tower
○ Physical machines die or get shut down
○ Campus ISP is slow or changes the IP
○ Limited scale: shipping a new PC takes days

5. 2012: Amazon EC2
● My next few startups all ran on 1-5 EC2 VMs
● Cloud VMs solve most physical machine issues
○ Power outages much less likely
○ Reliable internet maintained by Amazon
○ Spinning up a new VM takes minutes

6. 2012: Amazon EC2
● Vanilla EC2 was great for single server apps
● But what about multiple app servers?
○ 2 services on the same VM in isolation
○ Continuous Deployment
○ Scaling horizontally with a click

7. 2015: Containers and Orchestration
● Docker, Mesos, Kubernetes, etc.
● Compelling for CD and isolation
● Still Have Problems with Resource Usage
○ Memory limits per VM
○ Docker hogs disk space

8. Functions as a Service
● Instead of deploying an app, you deploy a
bunch of stateless functions
● No VMs, no OS updates
● Resource limits (RAM, CPU) per function call
● Functions run in response to triggers

9. API Gateways
● Cloud functions respond to triggers
● HTTP is a trigger, but what about:
○ API keys / auth
○ Rate limits
● FaaS providers have API Gateways for this

10. FaaS Providers
● Amazon AWS Lambda
● Microsoft Azure Functions
● Google Cloud Functions
● IBM Cloud Functions
● Oracle Cloud Fn
● LunchBadger, + many more

11. FaaS Open Source Libraries
● Kubeless
● OpenWhisk
● Fission

12. FaaS Advantages
● Easier to scale, no need to worry about too
much load on one service
● Cheaper for low-usage services
● Cheap and easy development environments
● Resource issues rare and easy to debug

13. FaaS Problems
● No strong best practices yet
● Completely different way of writing apps
● Limited language support
● Managing triggers and API Gateways
● Sometimes you want to retain state...

14. Why Retain State?
● Think about a persistent database connection

15. Stateless is a Big Performance Problem
● Connecting to a database on every function
call is slow

16. But You Can Retain Global State
● Put db handle in global scope

17. Common Trick Across FaaS Providers
● AWS Lambda: bit.ly/mongodb-lambda
● Azure Functions: bit.ly/mongodb-azure
○ Also With C#: bit.ly/csx-azure-state
● IBM Cloud: bit.ly/mongodb-ibm-cloud

18. Trade-offs Between Popular Providers
● AWS Lambda
● Azure Functions
● Google Cloud Functions

19. Size Restrictions
● Size limit per function (node_modules)
○ AWS Lambda: 50MB
○ Azure Functions: None (*)
○ Google Cloud: 100MB zipped, 500MB
unzipped

20. Primary Fee Structure
● AWS Lambda: $0.00001667 / GB-s, $0.20 / 1M
● Azure Functions: $0.000016 / GB-s, $0.20 / 1M
● Google Cloud: $0.0000025 / GB-s, $0.0000100
/ GHz-s

21. Hidden Fees: API Gateways
● AWS Lambda: $3.50 / 1M + data
● Azure Functions: no extra cost necessary
● Google Cloud Functions: no extra cost
necessary

22. Overall FaaS Recommendations
● Check out Azure Functions
● AWS Lambda and IBM Cloud are a mess

23. Further Reading
● My Blog:
○ bit.ly/mongodb-azure
○ bit.ly/mongodb-ibm-cloud

24. Thanks for Listening!