the good, bad and ugly of serverless
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Functions as a Service
Lambda
DynamoDB S3 Kinesis
Lambda
CloudFormation SWF CloudTrail SES Cognito API Gateway CloudWatchSNS
w
The serverless manifesto
• No machines, VMs, or containers visible in the programming model.
• Functions are the unit of deployment & scaling.
• Implicitly fault tolerant, as functions can run anywhere.
• Scales per request.
• Users can not over- or under-provision capacity.
• Permanent storage lives elsewhere.
• Never pay for idle, no cold servers or their costs.
• Bring your own code (BYOC).
• Metrics and logging are a universal right.
Latency
Latency
• Coldstarts add ~100ms latency• Up to ~10s for JVM based functions• Keep your functions warm
Latency
functions: hello: handler: handler.hello events: - http: path: hello method: get - schedule: rate(10 minutes)
Latency
https://www.iopipe.com/2016/09/understanding-aws-lambda-coldstarts/
Latency
0
0.0375
0.075
0.1125
0.15
0.1875
APIGW/Lambda ELB/EC2
time_
tola
l
Latency (Cross Region)
0
0.325
0.65
0.975
1.3
APIGW/Lambda ELB/EC2
time_
tota
l
Latency (Cross Region)
0
0.05
0.1
0.15
0.2
APIGW/Lambda ELB/EC2
time_
conn
ect
API Gateway
– Top Gear
“Ambitious, but rubbish.”
What API Gateway does?• Authentication• Caching• Input validation• Request and response mapping• Throttling• Stages• Environment variables• SDK generation
What API Gateway doesn’t?
• Integrate (well) with other AWS services
API Gateway
• No CloudFront edge cache• Lambda timeout at 10s (maybe 30s)• No Certificate Manager integration
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Configuration
Configuration
https://12factor.net/build-release-run
– Adam Wiggins (12 Factor App)
“The twelve-factor app stores config in environment variables.”
https://www.concurrencylabs.com/blog/configure-your-lambda-function-like-a-champ-sail-smoothly/
Local Environments
Debugging
Concurrent Execution Limit
DoS yourself
That’s not all
• No persistent state• 5 minute execution limit• No atomic deployments of a service• Immature tooling• Vendor control / lock-in• Service Discovery
Conclusion
Further reading
http://martinfowler.com/articles/serverless.html
https://www.iopipe.com/2016/09/understanding-aws-lambda-coldstarts/
https://www.concurrencylabs.com/blog/configure-your-lambda-function-like-a-champ-sail-smoothly/
https://github.com/serverless/serverless
https://charity.wtf/2016/05/31/operational-best-practices-serverless/
