FaaS or not to FaaS. Visible and invisible benefits of the Serverless paradigma. W-JAX 2019 Kazulkin and Bannes

FaaS or not to FaaS
Visible and invsible benefits of the Serverless paradigma
by Christian Bannes and Vadym Kazulkin, ip.labs GmbH

Contact
Vadym Kazulkin
ip.labs GmbH
v.kazulkin@iplabs.de
xing.com/profile/Vadym_Kazulkin
@VKazulkin
@ServerlessBonn (Meetup)
Christian Bannes
ip.labs GmbH
c.bannes@iplabs.de
xing.com/profile/Christian_Bannes

Ip.labs GmbH
Christian Bannes and Vadym Kazulkin @VKazulkin , ip.labs GmbH

Image: https://aws.amazon.com/de/lambda/features
Function as a Service
=
AWS Lambda

Image: https://aws.amazon.com/de/lambda/features
Serverless is more than

Image: https://www.infoq.com/articles/serverless-sea-change/
Typical Three-Tier

Image: https://www.infoq.com/articles/serverless-sea-change/

Platform
cost
Image: https://stocksnap.io

Velocity of
your team
Image: https://burst.shopify.com

What you really have
to consider
Total Cost of
Ownership

Lambda pricing model

Cost for lambda
REQUEST DURATION

Request Tier
$ 0.20
Per 1 Mio Requests

Duration Tier
$ 0.00001667
Per GB-Second

GB-Second
ONE SECOND ONE GB

Example
• 1 Mio requests
• Lambda with 512MiB
• Each lambda takes 200ms
0.5 GiB * 0.2 sec * 1 Mio
= 100 000 GB-Seconds
Requests:
$0.20
GB-Seconds:
$1.67

Cost scales
linearly with
memory

How does this compare to
VM pricing model?

Lambda performance
compares to
• M4 (general purpose)
• M5 (general purpose)
EC2 Instance
Families

M5 General Purpose Instance
Cost scales linearly
with memory

Lamdba vs VM
https://www.youtube.com/watch?v=b1ebYEfQX1s

Lambda compute is
5x more expensive than M5

Threading Model
Idle Idle
Pay per wall clock time Pay per use

Image: https://aws.amazon.com
AWS monetizes the datacenter…
… by selling time on their servers

Common pitfalls when
working with lambda

More memory = more expensive?

Power tuning
lambda
• Executes different
settings in parallel
• Outputs the optimal
setting
Image: https://github.com/alexcasalboni/aws-lambda-power-tuning

The reality is…
Lambda is often just a
small percentage
of your total cost

$ 3.50
Per million API calls
API Gateway

Event Sources
• SQS and SNS are
charged for requests
• Kinesis charges for
shard hours & PUT
requests
Image: https://blog.binaris.com/lambda-pricing-pitfalls/

Event Sources
• Cost for Kinesis grows
with slower rate
• Attractive at to
operate at scale
Image: https://blog.binaris.com/lambda-pricing-pitfalls/

DynamoDB On-Demand
Image: https://aws.amazon.com/blogs/aws/amazon-dynamodb-on-
demand-no-capacity-planning-and-pay-per-request-pricing/

Provisioned vs
On-Demand
• Use On-Demand for
spiky workloads
• Use Provisioned for
constantly high
workload

Cost saving with
On-Demand
Image: https://twitter.com
Switch to
"On-Demand"

Serverless vs VM
• "Pay as you go" can significantly reduce server cost
because you don’t pay for ide time
• For serverless you need right architecture
• Consider the Total Cost of Ownership

What you really have
to consider:
Total Cost of
Ownership

Ajay Nair
https://twitter.com/ajaynairthinks/status/1057696133076541441

TCO Full Picture
Forrest Brazeal „The Business Case For Serverless”
https://www.trek10.com/blog/business-case-for-serverless/
No Infrastructure
Maintanence
Auto Scaling
Built in
Less Code with
Fewer Engineers
Lower Software
Maintenance Cost
/ Lower Technical
Debt
Focus on Business
Value & Innovation
Faster Time to
Market

Do more with (Server-)less

Image: https://stock.adobe.com

1. Application lifecycle
2. Workloads
3. Platform limitations
4. Cost at scale
5. Operational constraints
6. Organizational knowledge
7. Platform and tooling maturity
Decision Checklist

Understand
Application
lifecycle
Christian Posta „Be as serverless as you can, but not more than that”
https://blog.christianposta.com/serverless/
its-not-about-microservices-vs-serverless/

Explore phase
• Quickly validate
hypotheses
• Rapidly experiment
• Run experiments as
cheaply as possible
Image: burst.shopify.com/photos/a-look-across-the-landscape
-with-view-of-the-sea
Serverless is a perfect fit

Exploit phase
• Built something that does
provide customer value
• Build it on scale
• Build a profitable product
around it
Image: Robert Scoble via Flickr
partly serverless and partly not
serverless architecture

Application lifecycle
• How much of my stack should I own
to be able to deliver business value?
• Outsource SLA, regulatory
compliance, price, support, and
roadmap to my service provider?

Existing
applications
• You can’t magically move
that all off to service
providers
• You can try to modernize
parts of them

Strangler
Pattern
• Add a proxy (API
Gateway or Application
Loadbalancer), which
sits between the legacy
application and the user
• Add new services and
link it to the proxy
Marin Fowler „StrangerFigApplication”
https://martinfowler.com/bliki/StranglerFigApplication.html

FinDev Concept
Activity-based costing on a
digital operation-by-operation
basis
• Figure out features which deliver
business value comparing to their
cost
Aleksander Simovic & Mark Schwarz
„FinDev and Serverless Microeconomics: Part 1”
https://aws.amazon.com/de/blogs/enterprise-strategy
/findev-and-serverless-microeconomics-part-1/

2. Workloads
4. Cost at scale
5. Operational constraints imposed by other dependencies

Understand your
workloads
• Event-driven
• API-driven
• Batch Job
• ML/AI
• Big Data
Image: flickr.com/photos/everywhereatonce/294789504

Lambda Layers
& Lambda
Runtime API
Door opener for use
case like:
• Big Data
• ML/AI

Understand your workloads
• Do we need to access specialized
hardware ?
• GPU access required?
• Another RAM/CPU ratio?
• Do we need constantly high
performance?
• Response time below 100 ms
(e.g. bidding or gaming platforms)
“A Berkeley View on Serverless Computing”
https://www2.eecs.berkeley.edu/Pubs/TechRpts/2
019/EECS-2019-3.html

• Do we need high throughput ?
• Lambda‘s network bandwidth is limited
(an order of magnitude lower than a
single modern SSD) shared between all
functions packed on the same VM

Storage TradeOffs
Latency
Scaling Pricing
Consistency

S3 Storage TradeOffs
Latency
Scaling Pricing
Consistency

The State of Serverless Computing
“Chenggang Wu & Vikram Sreekanti –
The State of Serverless Computing” Craft Conference
2019 - Budapest , Hungary
https://www.youtube.com/watch?v=htLQiSPMUmk&
list=LLYgjRSI2oCzI9eooyFrWR7A&index=6

Anna Key-Value Store
• Anna is Fast, Super-Scalable, Flexibly
Consistent Key-Value Stored developed
by Berkley
“Anna Key-Value Store”
https://rise.cs.berkeley.edu/blog/anna-kvs/
http://highscalability.com/blog/2018/9/8/the-anna-key-value-
store-now-has-355x-the-performance-of-dyn.html

• Do functions need to communicate with
each other?
• functions are not directly network
accessible, they must communicate via
an intermediary service

Serverless Networking (beta)
• Serverless Networking is double-NAT-
punching system that allows to connect
two Lambda functions to each other or
to connect a server-based
implementation to a Lambda.
• Works by using API Gateway as a
broker to let Lambdas register, find each
other, and set up connections.
“Serverless Networking”
https://read.acloud.guru/https-medium-com-timawagner
-serverless-networking-the-next-step-in-serverless-
evolution-95bc8adaa904

2. Workloads
4. Cost at scale
5. Operational constraints imposed by other dependencies

Understand platform
limitations
• Cold start
• Lambda with and without VPC for
each runtime

Ajay Nair „Become a Serverless Black Belt”
https://www.youtube.com/watch?v=oQFORsso2go

Lambda in VPC
Chris Munns "Announcing improved VPC networking
for AWS Lambda functions"
https://aws.amazon.com/de/blogs/compute/announcing-improved-
vpc-networking-for-aws-lambda-functions/

Lambda in VPC
As function’s execution environment
scales
• More network interfaces are created and
attached to the Lambda infrastructure.
• The exact number of network interfaces
created and attached is a factor of your
function configuration and concurrency.

Lambda in VPC
As your function scales, be mindful of
several issues:
• Managing the IP address space in your
subnets
• Reaching the account level elastic network
interface limit

NEW: Lambda in VPC:
Leveraging AWS Hyperplane to
provide NAT capabilities from the
Lambda VPC to customer VPCs

NEW: Lambda in VPC:
• The network interface creation happens
when Lambda function is created or its
VPC settings are updated.
• Function scaling is no longer directly tied to
the number of network interfaces
• Hyperplane ENIs can scale to support
large numbers of concurrent function
executions

Testing improvements to
Lambda VPC Networking
Testing improvements to Lambda VPC Networking
https://teachmyselfcloud.com/post/lambda-vpc-networking.html
VPC attached Lambda in the EU-Ireland
region (optimization not yet rolled out)
VPC attached Lambda in the EU-Frankfurt
region (optimization already rolled out)

Amazon Aurora
Serverless Data
API
as beta for
MySql and
Postgres
available
https://docs.aws.amazon.com/de_de/AmazonRDS/latest/
AuroraUserGuide/data-api.html

Don‘t be scared
of cold starts
To avoid cold starts them
completely, you have to :
• Overpay
• Overprovision
Cold starts don’t really
matter if the you make
the call asynchronously

Understand platform
limitations
• Cold start
• Lambda with and without VPC for
each runtime
• Invocation duration/timeouts
• Lambda 15min
• API Gateway integration 29sec
• Max Memory
• Lambda 3GB

Understand platform
limitations
• Max concurrent invocations
• Soft limit of 1000-3000 parallel
executions for all Lambdas in each
AWS account

Understand your cost at scale
• Lambda
• API Gateway
• Dynamo DB capacity choices
• Logging costs
• Monitoring costs

Understand your cost at scale
• Data transfer costs
• X-Ray
• Step functions
• Caching costs (API Gateway, DAX for
Dynamo DB)
• Remote API calls
• 3rd party Services price models

2. Workloads
4. Cost at scale
5. Operational constraints

Understand the operational constraints
• Language runtime choice
• Can be forced by some dependencies to
other libraries
Yan Cui „Not so FaaS” https://blog.binaris.com/not-so-faas/ Christian Bannes and Vadym Kazulkin @VKazulkin , ip.labs GmbH

Understand organizational
knowledge
• Do you already have
DevOps knowledge?

Tom McLaughlin Talk:
What do we do when
the server goes away?
• Monitoring & Alerting
• Chaos Engineering & Game Days
• Infrastructure as Code & Testing
• Help understand constraints
of AWS services & choose the right
one
Tom McLaughlin „What do we do when the server goes away”
https://speakerdeck.com/tmclaugh/serverless-devops-what-do-
we-do-when-the-server-goes-away

Understand organizational
knowledge
• Do you already have
DevOps knowledge?
• Are the developers willing to
learn new languages?

Serverless platform and tooling maturity
• Infrastructure-as-a-Code
solutions maturity (CF, CDK)
• Development environment &
framework maturity (e.g.
Serverless Framework, AWS
SAM, AWS Amplify)
• Tooling maturity (CI/CD,
logging, tracing, monitoring /
observability, alerting,
security)
Image: http://tea.solgenomics.net/anatomy_viewer/
microscopy/slm82_fruit

Serverless platform and tooling maturity
• Integration with 3rd party SaaS
• Local testing and debugging
Image: http://tea.solgenomics.net/anatomy_viewer/
microscopy/slm82_fruit

Berkeley View on
Serverless Computing

Grady Booch
Drivers in the evolution of computing
• Raising level of abstraction
• Economics

Simon Wardley https://twitter.com/swardley/status/1017074876887322627

Wardley Map
Simon Wardley https://www.slideshare.net/swardley/
why-the-fuss-about-serverless-88107645

Berkeley View on
Serverless Computing
• Provide low latency and high IOPS
Serverless Ephemeral Storage
• Provide Serverless Durable Storage
• Improve Networking and Performance
• Improve Security
• Accommodate cost-performance

• Application lifecycle
• Workloads
• Platform limitations
• Cost at scale
• Operational constraints
• Organizational knowledge
• Platform and tooling maturity
FaaS or not to FaaS

Thank You!

FaaS or not to FaaS. Visible and invisible benefits of the Serverless paradigma. W-JAX 2019 Kazulkin and Bannes

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