This document discusses serverless architectural patterns and best practices using AWS services like AWS Lambda, Amazon API Gateway, Amazon S3, Amazon DynamoDB, and Amazon Kinesis. It covers four common patterns: 1) 3-tier web applications, 2) batch processing, 3) stream processing, and 4) automation. For each pattern, it discusses considerations, example architectures, and best practices. It provides guidance on designing resilient and scalable serverless applications and systems.

1. © 2016, Amazon Web Services, Inc. or its Affiliates. All rights reserved.
Daniel Geske <gesked@amazon.de>
24 August 2017
Serverless Architectural
Patterns and Best Practices

2. Agenda
Serverless characteristics and practices
3-tier web application
Batch processing
Stream processing
Operations automation
Wrap-up/Q&A

3. Spectrum of AWS offerings
AWS
Lambda
Amazon
Kinesis
Amazon
S3
Amazon API
Gateway
Amazon
SQS
Amazon
DynamoDB
AWS IoT
Amazon
EMR
Amazon
ElastiCache
Amazon
RDS
Amazon
Redshift
Amazon
Elasticsearch
Service
Managed Serverless
Amazon EC2
“On EC2”
Amazon
Cognito
Amazon
CloudWatch

4. Serverless patterns built with functions
Functions are the unit of deployment and scale
Scales per request—users cannot over or under-provision
Never pay for idle
Skip the boring parts; skip the hard parts

5. Lambda considerations and best practices
AWS Lambda is stateless—architect accordingly
• Assume no affinity with underlying compute
infrastructure
• Local filesystem access and child process may not
extend beyond the lifetime of the Lambda request

6. Lambda considerations and best practices
Can your Lambda functions
survive the cold?
• Instantiate AWS clients and
database clients outside the
scope of the handler to take
advantage of connection re-use.
• Schedule with CloudWatch
Events for warmth
• ENIs for VPC support are
attached during cold start
import sys
import logging
import rds_config
import pymysql
rds_host = "rds-instance"
db_name = rds_config.db_name
try:
conn = pymysql.connect(
except:
logger.error("ERROR:
def handler(event, context):
with conn.cursor() as cur:
Executes with
each invocation
Executes during
cold start

7. Lambda considerations and best practices
How about a file system?
• Don’t forget about /tmp (512 MB
scratch space)
exports.ffmpeg = function(event,context)
{
new ffmpeg('./thumb.MP4', function (err,
video)
{
if (!err) {
video.fnExtractFrameToJPG('/tmp’)
function (error, files) { … }
…
if (!error)
console.log(files);
context.done();
...

8. Lambda considerations and best practices
Custom CloudWatch metrics
• 40 KB per POST
• Default Acct Limit of 150 TPS
• Consider aggregating with Kinesis
def put_cstate ( iid, state ):
response = cwclient.put_metric_data(
Namespace='AWSx/DirectConnect',
MetricData=[
{
'MetricName':'ConnectionState',
'Dimensions': [
{
'Name': 'ConnectionId',
'Value': iid
},
],
'Value': state,
'Unit': 'None’
…

9. Pattern 1: 3-Tier Web Application

10. Web application
Data stored in
Amazon
DynamoDB
Dynamic content
in AWS Lambda
Amazon API
Gateway
Browser
Amazon
CloudFront
Amazon
S3

11. Amazon API
Gateway AWS
Lambda
Amazon
DynamoDB
Amazon
S3
Amazon
CloudFront
• Bucket Policies
• ACLs
• OAI
• Geo-Restriction
• Signed Cookies
• Signed URLs
• DDOS
IAM
AuthZ
IAM
Serverless web app security
• Throttling
• Caching
• Usage Plans
Browser

12. Amazon API
Gateway AWS
Lambda
Amazon
DynamoDB
Amazon
S3
Amazon
CloudFront
• Bucket Policies
• ACLs
• OAI
• Geo-Restriction
• Signed Cookies
• Signed URLs
• DDOS
IAMAuthZ IAM
Serverless web app security
• Throttling
• Caching
• Usage Plans
Browser
Amazon
CloudFront
• HTTPS
• Disable Host
Header Forwarding
AWS WAF

13. Amazon API
Gateway
AWS
Lambda
Amazon
DynamoDB
Amazon
S3
Amazon
CloudFront
• Access Logs in S3
Bucket• Access Logs in S3 Bucket
• CloudWatch Metrics-
https://aws.amazon.com/
cloudfront/reporting/
Serverless web app monitoring
AWS WAF
• WebACL Testing
• Total Requests
• Allowed/Blocked
Requests by ACL
logslogs
• Invocations
• Invocation Errors
• Duration
• Throttled
Invocations
• Latency
• Throughput
• Throttled Reqs
• Returned Bytes
• Documentation
• Latency
• Count
• Cache Hit/Miss
• 4XX/5XX Errors
Streams
AWS
CloudTrail
Browser
Custom CloudWatch
Metrics & Alarms

14. Serverless web app lifecycle management
AWS SAM (Serverless Application Model) - blog
AWS
Lambda
Amazon API
Gateway
AWS
CloudFormation
Amazon
S3
Amazon
DynamoDB
Package &
Deploy
Code/Packages/
Swagger
Serverless
Template
Serverless
Template
w/ CodeUri
package deploy
CI/CD Tools

15. Amazon API Gateway best practices
Use mock integrations
Signed URL from API Gateway for large or binary file
uploads to S3
Use request/response mapping templates for legacy
apps and HTTP response codes
Asynchronous calls for Lambda > 30s

16. Root/
/{proxy+} ANY Your Node.js
Express app
Greedy variable, ANY method, proxy integration
Simple yet very powerful:
• Automatically scale to meet demand
• Only pay for the requests you receive

17. Pattern 2: Batch Processing

18. Characteristics
Large data sets
Periodic or scheduled tasks
Extract Transform Load (ETL) jobs
Usually non-interactive and long running
Many problems fit MapReduce programming model

19. Serverless batch processing
AWS Lambda:
Splitter
Amazon S3
Object
Amazon DynamoDB:
Mapper Results
AWS Lambda:
Mappers
….
….
AWS Lambda:
Reducer
Amazon S3
Results

20. Considerations and best practices
Cascade mapper functions
Lambda languages vs. SQL
Speed is directly proportional to the concurrent Lambda
function limit
Use DynamoDB/ElastiCache/S3 for intermediate state of
mapper functions
Lambda MapReduce Reference Architecture

21. Cost of serverless batch processing
200 GB normalized Google Ngram data-set
Serverless:
• 1000 concurrent Lambda invocations
• Processing time: 9 minutes
• Cost: $7.06

22. Pattern 3: Stream Processing

23. Stream processing characteristics
• High ingest rate
• Near real-time processing (low latency from ingest to
process)
• Spiky traffic (lots of devices with intermittent network
connections)
• Message durability
• Message ordering

24. Serverless stream processing architecture
Sensors
Amazon Kinesis:
Stream
Lambda:
Stream Processor
S3:
Final Aggregated Output
Lambda:
Periodic Dump to S3
CloudWatch Events:
Trigger every 5 minutes
S3:
Intermediate Aggregated
Data
Lambda:
Scheduled Dispatcher
KPL:
Producer

25. Fan-out pattern
• Number of Amazon Kinesis Streams shards corresponds to concurrent
Lambda invocations
• Trade higher throughput & lower latency vs. strict message ordering
Sensors
Amazon Kinesis:
Stream
Lambda:
Dispatcher
KPL:
Producer Lambda:
Processors
Increase throughput, reduce processing latency

26. More about fan-out pattern
• Keep up with peak shard capacity
• 1000 records / second, OR
• 1 MB / second
• Consider parallel synchronous Lambda invocations
• Rcoil for JS (https://github.com/sapessi/rcoil) can help
• Dead letter queue to retry failed Lambda invocations

27. Best practices
• Tune batch size when Lambda is triggered by Amazon
Kinesis Streams – reduce number of Lambda
invocations
• Tune memory setting for your Lambda function – shorten
execution time
• Use KPL to batch messages and saturate Amazon
Kinesis Stream capacity

28. Monitoring
Amazon Kinesis Stream metric GetRecords.IteratorAgeMilliseconds maximum

29. Amazon Kinesis Analytics
Sensors
Amazon Kinesis:
Stream
Amazon Kinesis Analytics:
Window Aggregation
Amazon Kinesis Streams
Producer S3:
Aggregated Output
CREATE OR REPLACE PUMP "STREAM_PUMP" AS INSERT INTO
"DESTINATION_SQL_STREAM"
SELECT STREAM "device_id",
FLOOR("SOURCE_SQL_STREAM_001".ROWTIME TO MINUTE) as "round_ts",
SUM("measurement") as "sample_sum",
COUNT(*) AS "sample_count"
FROM "SOURCE_SQL_STREAM_001"
GROUP BY "device_id", FLOOR("SOURCE_SQL_STREAM_001".ROWTIME TO MINUTE);
Aggregation
Time Window

30. Cost comparison - assumptions
• Variable message rate over 6 hours
• Costs extrapolated over 30 days
20,000
10,000
20,000
50,000
20,000
10,000
1 2 3 4 5 6
MESSAGES/SEC
HOURS

31. Serverless
• Amazon Kinesis Stream with 5
shards
Cost comparison
Server-based on EC2
• Kafka cluster (3 x m3.large)
• Zookeeper cluster (3 x m3.large)
• Consumer (1 x c4.xlarge)
Service Monthly Cost
Amazon Kinesis Streams $ 58.04
AWS Lambda $259.85
Amazon S3 (Intermediate Files) $ 84.40
Amazon CloudWatch $ 4.72
Total $407.01
Service Monthly Cost
EC2 Kafka Cluster $292.08
EC2 Zookeeper Cluster $292.08
EC2 Consumer $152.99
Total On-Demand $737.15
1-year All Upfront RI $452.42

32. Compare related services
Amazon Kinesis Streams Amazon SQS Amazon SNS
Message Durability Up to retention period Up to retention period Retry delivery (depends on
destination type)
Maximum Retention Period 7 days 14 days Up to retry delivery limit
Message Ordering Strict within shard Standard - Best effort
FIFO – Strict within Message
Group
None
Delivery semantics Multiple consumers per
shard
Multiple readers per queue (but
one message is only handled
by one reader at a time)
Multiple subscribers per
topic
Scaling By throughput using Shards Automatic Automatic
Iterate over messages Shard iterators No No
Delivery Destination Types Kinesis Consumers SQS Readers HTTP/S, Mobile Push,
SMS, Email, SQS, Lambda

33. Lambda architecture
Data
Sources
Serving Layer
Speed Layer
AWS Lambda:
Splitter
Amazon S3
Object
Amazon DynamoDB:
Mapper Results
Amazon
S3
AWS Lambda:
Mappers
….
….
AWS Lambda:
Reducer
Amazon S3
Results
Batch Layer
Sensors
Amazon Kinesis:
Stream
Lambda:
Stream Processor
S3:
Final Aggregated Output
Lambda:
Periodic Dump to S3
CloudWatch Events:
Trigger every 5 minutes
S3:
Intermediate Aggregated
Data
Lambda:
Scheduled Dispatcher
KPL:
Producer

34. Pattern 4: Automation

35. Automation characteristics
• Respond to alarms or events
• Periodic jobs
• Auditing and Notification
• Extend AWS functionality
…All while being Highly Available and Scalable

36. Automation: dynamic DNS for EC2 instances
AWS Lambda:
Update Route53
Amazon CloudWatch Events:
Rule Triggered
Amazon EC2 Instance
State Changes
Amazon DynamoDB:
EC2 Instance Properties
Amazon Route53:
Private Hosted Zone
Tag:
CNAME = ‘xyz.example.com’
xyz.example.com A 10.2.0.134

37. Automation: image thumbnail creation from S3
AWS Lambda:
Resize Images
Users upload photos
S3:
Source Bucket
S3:
Destination Bucket
Triggered on
PUTs

38. CapitalOne Cloud Custodian
AWS Lambda:
Policy & Compliance Rules
Amazon CloudWatch Events:
Rules Triggered
AWS CloudTrail:
Events
Amazon SNS:
Alert Notifications
Amazon CloudWatch Logs:
Logs
Read more here: http://www.capitalone.io/cloud-custodian/docs/index.html

39. Best practices
• Document how to disable event triggers for your automation when
troubleshooting
• Gracefully handle API throttling by retrying with an exponential back-
off algorithm (AWS SDKs do this for you)
• Publish custom metrics from your Lambda function that are
meaningful for operations (e.g. number of EBS volumes
snapshotted)

40. Go build something.
Daniel Geske <gesked@amazon.de>