Slides from a talk at SyntaxCon 2017

1. Serverless - AWS Lambda Deep Dive
Alfonso Cabrera
SyntaxCon 2017

2. $ whoami
Cloud Engineer @ Red Ventures
DevOpsDays Charlotte Organizer
Team Luna member (teamluna.co)
@alfonso__c

3. serverless

4. The hype is real

5. serverless?

6. FaaS
Functions as a service

8. By Definition
"... code execution model in which the cloud provider fully
manages starting and stopping of a function's container
platform as a service (PaaS) as necessary to serve requests,
and requests are billed by an abstract measure of the
resources required to satisfy the request, rather than per
virtual machine, per hour."
— Wikipedia

9. Benefits
cost
focus on code, not infra
no server patching or maintenance
free reliability and scalability

10. So, what is Lambda?
AWS offering of Faas launched at re:Invent 2014
Officially supports C#, Java, NodeJS, Python
Pricing based on function execution requests, duration
and assigned memory

11. Runtime Environment
Amazon Linux AMI (RHEL-based w kernel v4.4) container
with function code
Node 4.3.2 & 6.10, Java 8, Python 2.7 & 3.6, .NET Core 1.0.1
AWS SDK library included
Supports KMS encrypted environment variables
Memory from 128 to 1536 MB

12. Default Limits
/tmp space = 512 MB
Max execution time = 300 seconds
Total processes & threads = 1024
Concurrent executions = 1000
Deployment package size = 50 MB

13. Common Code Model
Handler function: entry point & gets event data
Context object: contains runtime info
Code should be stateless
Do or do not; there is no try (return success or failure)

14. print('Starting function!')
def my_handler(event, context):
message = 'Hello {} {}!'.format(event['first_name'],
event['last_name'])
return {
'message' : message
}

15. def get_context(event, context):
print("Log stream name:", context.log_stream_name)
print("Log group name:", context.log_group_name)
print("Request ID:", context.aws_request_id)
print("Mem. limits(MB):", context.memory_limit_in_mb)
print("Time remaining (MS):", context.get_remaining_time_in_millis())

16. Event sources
Event sources are the heart of event-driven apps
Vary on async vs sync invocation
Custom sources supported with Invoke API
S3, Cloudwatch, Kinesis, Dynamo, API Gateway plus
many more

17. Packaging
Zip files!
Deploy packages must be < 50 MB
Other options available for C#, Java & Python
Honestly, just use a framework

18. Frameworks - Apex
apex.run
Unix philosophy
Project structure w/ multiple envs and functions
Also supports golang, clojure and rust
Integrates with terraform for infra

19. Frameworks - Serverless
serverless.com
Better support for mapping event sources
Runs cloudformation to provision resources
Supports C# functions

20. Water Break

21. Logging
Add logs to your code!
They get shipped to Cloudwatch:
/aws/lambda/<function_name>
Lambda console, cloudwatch, or x-amz-log-results
response header

22. Monitoring
Look at 3rd party tools
Instrument and/or trace your code - AWS Xray!
Metrics sent to Cloudwatch:
- Invocations
- Errors
- Duration
- Throttles

23. Retries
stream based vs non-stream based
non-stream & synchronous - client should add retry
logic
non-stream & async - auto retry twice with delays then
discarded*
stream - will retry until success or until data expires

24. Networking
To VPC or not to VPC?
All inbound network connections are blocked
Outbound connections are TCP only

25. Permissions
IAM policies for all the things
VPC function? Start with AWSLambdaVPCAccessExecutionRole

26. Security
No vulnerabilities through unpatched servers
DDoS becomes just a billing issue
Immutability eliminates compromised servers
You still own security in your code!

27. Pricing
It gets complicated...

28. Requests Pricing
First 1 million requests per month are free!
20 cents per 1 million requests thereafter

29. Duration Pricing
Code execution time, rounded up to nearest 100 ms
Price is dependent on memory allocation using GB-
seconds formula
You get 400,000 GB-seconds free per month
$0.00001667 per GB-s thereafter

30. Pricing example
Function gets 3m requests per
month and takes 1s per request.
512 mb memory allocation:
3m requests * 1s = 3,000,000
3,000,000 * 512mb / 1024 =
1,500,000 GB-s
1,500,000 - 400,000 (free tier) =
1,100,000 GB-s
1,100,000 * $0.00001667 = $18.74
Total cost: $18.74 month

34. Lambda @ Edge
Run functions @ Cloudfront Edge locations for:
- requests
- origin responses
- origin requests
- viewer responses
Only supports NodeJS 4.3

35. Step Functions
Visual workflow for orchestrating functions

36. Xray
End to end distributed tracing
Service maps
Lambda tracing in preview
Currently supports Java, .NET & NodeJS

37. Useful tips
DB connections outside of handler
Take advantage of warm containers (if feasible)
Arbitrary executables
CPU power proportionate to RAM

38. Gotchas
Background processes
File permissions
Missing logs or errors
Console magic
Be careful with concurrency limits!

39. Thank You!