https://community-z.com/events/zed-compass/talks/13971

1. Serverless
patterns & best-
practices in AWS
Dima Pasko, SA

2. This presentation has been prepared by EPAM Systems, Inc. solely for use by EPAM at its EPAM Zed
Conference. This presentation or the information contained herein may not be reproduced or used
for any other purpose. This presentation includes highly confidential and proprietary information and
is delivered on the express condition that such information will not be disclosed to anyone except
persons in the recipient organization who have a need to know solely for the purpose described
above. No copies of this presentation will be made, and no other distribution will be made, without
the consent of EPAM. Any distribution of this presentation to any other person, in whole or in part,
or the reproduction of this presentation, or the divulgence of any of its contents is unauthorized.
CONFIDENTIAL INFORMATION

3. Dima Pasko
Solution Architect II
EPAM Systems

4. What Serverless Is
Serverless computing is a cloud computing execution model in which the cloud provider
allocates machine resources on demand, taking care of the servers on behalf of their customers…
© Wikipedia https://en.wikipedia.org/wiki/Serverless_computing

5. The Business Case
For Serverless

6. Focus on business value, not infrastructure
1. F A S T E R T I M E T O M A R K E T
2.
3.
R E D U C E D C O S T S
I M P R O V E D R E L I A B I L I T Y
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4. I N C R E A S E D R AT E O F I N N O VAT I O N

7. Faster time to market
By eliminating operational overhead, your teams can release quickly, get
feedback, and iterate to get to market faster.

8. Reduced costs
With a pay-for-value billing model, you never pay for over-provisioning and
your resource utilization is optimized on your behalf.

9. Improved reliability
With technologies that automatically scale from zero to peak demands, you
can adapt to customer needs faster than ever.

10. Increased rate of innovation
Serverless applications have built-in service integrations, so you can focus on
building your application instead of configuring it.

11. AWS Serverless Design
Patterns & Solutions
Review

12. AWS Lambda/Serverless patterns overview
AWS designed many solutions, and you should just find building
blocks for your cases
• Web application
• Mobile application for social distancing
• Mobile back-end
• Real-time stream processing
• IoT back-end
• AWS Connected mobility architecture
• Real-time file processing
• MapReduce
• Image recognition & processing
• Image moderator chatbot
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https://aws.amazon.com/lambda/resources/reference-architectures/

13. AWS Serverless Application Lens
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AWS Well-Architected Tool
AWS Well-Architected Framework
Serverless Lens
FTR Lens
SaaS Lens
Operational excellence
Security
Reliability
Performance efficiency
Cost Optimization
Workload Review Report

14. AWS Serverless Application Lens Report Example (General)
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15. AWS Serverless Application Lens Report Example (Details)
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16. Serverless Myths &
Design Anti-Patterns

17. Myths
Myth #1: Serverless means “no server and hardware”
• You need to setup required RAM size
Myth #2: Serverless == Lambda (AWS Lambda, Azure Functions etc.)
• Amazon enumerates as serverless such services as S3, SQS, SNS, API Gateway, DynamoDB
Myth #3: Serverless is cheap, definitely cheaper than “serverfull” solution
• Not always, you always should calculate costs ahead to see if it’s good fit

18. Going Stateful Anti-Pattern
Antipattern #1: Going stateful (in-memory state)
Problem
• Though lambda instance can be preserved for the next requests (such called
“hot start”), it is not guaranteed
• After lambda run, lambda instance can be terminated anytime
Solution
• You need a state, store it in external services
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19. Do Not Pay Attention To Service Specifics
Antipattern #2: Do not pay attention to service specifics
Problem
• “I just write my code and deploy it to AWS Lambda – and everything works” – right, but only if
you agree with terms of service. AWS Lambda for example, have number of limitations (quotas):
• Request size <= 6Mb (so you cannot use it for file upload, use S3 for that)
• Max execution time is 15 minutes (lambda is terminated by timeout then)
Solution
• Regularly revisit quotas, know your data, check if they fit
• Remember there are hard and soft limits, soft limits can be increased on request
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20. My Favorite Stack Is Great At Lambdas
Antipattern #3: Use your favorite tech stack without paying attention at cost
Problem
• Startup can be much slower in comparison to using plain old java or another language
• You are charged on a second basis.
Reducing overall duration from 10 seconds to 5 seconds will cut your costs twice
• Decreasing memory size (because code in Java was rewritten in Go) by two times will cut your costs
twice
Solution
• As lambda should be small, you can write it in Go/Python/JavaScript even if you are not a Pro in this
language
• So the pattern is: consider if the cost benefit worth learning
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21. Multithreading Is Great In Lambdas
Antipattern #4: Using old-fashioned way for orchestration
Problem
“I will save a record in DynamoDB from lambda
and then Thread.sleep for another service to update it’s status”
• Each second if lambda does not do anything, you still pay money
• Avoid explicit and try to avoid implicit waits
• Implicit wait – blocking lambda instance awaiting for response from synchronous calls (RESTs)
• Explicit wait – Thread.sleep, polling messages from queues in while loops, checking state in while loops
etc.
Solution
• Orchestration using AWS Step Functions
• Choreography using message brokers (SQS, EventBridge, Kinesis, DynamoDB Streams)
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22. Serverless Best Practices

23. Serverless Application Model
• Build serverless applications in simple and clean syntax
• Features:
• Built on AWS CloudFormation
• Built-In Best Practices
• Single Deployment Configuration
• Local Testing and Debugging
(+ https://localstack.cloud/)
• Serverless Application Model - https://aws.amazon.com/serverless/sam/

24. AWS CDK
• Define cloud infrastructure using familiar programming languages
• Supported programming languages:
• TypeScript
• Java Script
• Python
• Java
• C# (.NET)
• AWS Solutions Constructs -
https://aws.amazon.com/solutions/constructs/patterns/
• ConstructHub - https://constructs.dev/
• CDK Patterns - https://cdkpatterns.com/

25. Nested Stacks
• Nested stacks are stacks created as part of other stacks.
• Nested stacks can themselves contain other nested stacks, resulting in a
hierarchy of stacks, as in the diagram below. The root stack is the top-
level stack to which all the nested stacks ultimately belong. In addition,
each nested stack has an immediate parent stack. For the first level of
nested stacks, the root stack is also the parent stack. in the diagram
below, for example:
• Stack A is the root stack for all the other, nested, stacks in the hierarchy.
• For stack B, stack A is both the parent stack, and the root stack.
• For stack D, stack C is the parent stack; while for stack C, stack B is the
parent stack.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-
cfn-nested-stacks.html

26. Know Your Limits
• Lambda’s executions
• Concurrent executions - 1,000
• Step Functions
• Maximum number of registered state machines - 10,000
• Maximum open executions per account - 1,000,000 executions
per AWS account.
• ENIs for Lambdas are not endless
• Elastic network interfaces per virtual private cloud (VPC) - 250
• Limit on S3 buckets for Lambdas
• Buckets - 100 per account

27. AWS Lambda Power Tuning
AWS Lambda Power Tuning is a state machine powered by AWS Step Functions that helps you optimize your Lambda functions for cost
and/or performance in a data-driven way.
https://github.com/alexcasalboni/aws-lambda-power-tuning

28. DB Connections Management
Serverless works best with services rather than connections.
Connection management:
• Application connection pooling
• RDS Proxy
• Amazon Aurora Serverless v2
• Data API
• Dynamo DB
• https://aws.amazon.com/blogs/database/best-practices-for-working-
with-amazon-aurora-serverless/

29. Thank you!
For more information, contact
Dima Pasko
Solution Architect II
Dmytro_Pasko@epam.com
https://www.linkedin.com/in/dimapasko