DCEU 18: Docker Containers in a Serverless World

Jules Testard
Software Engineer, Docker
Inc
Docker Containers in
the Serverless World

What is Serverless?
● Serverless: also called FaaS
● FaaS: Function-As-A-Service
● Programming model in which applications are written as a set of
“functions”, run in ephemeral containers
package function
import (
"encoding/json"
)
// Handle a serverless request
func Handle(req []byte) string {
var e CloudEvent
if err := json.Unmarshal(req, &e); err != nil {
panic(err)
}
if Authenticate(e.Data) {
return "authentication successful"
}
return "authentication failed"
}

What is Serverless?
Public Cloud FaaS
● Public cloud manages the
function lifecycle and execution
● “Pay-as-you-go” model. Pricing is
based on actual amount of
resources consumed by the
function execution
● Pioneered by AWS, with AWS
Lambda (2014)
Private/Installable FaaS
● Installed using an orchestrator
such as Docker Swarm or
Kubernetes on a cluster
● Function management and
lifecycle handled in orchestrator.
● More recently developed (2016).
● Serverless: also called FaaS
● FaaS: Function-As-A-Service
● Programming model in which applications are written as a set of
“functions”, run in ephemeral containers

Serverless Pros
● Eliminates server maintenance
○ Developer time is spent on building actual value
○ (installable framework) -> maintenance goes to ops team
● Automatic Scaling
● Significant Price Drop
● Modernize traditional application (MTA)

LibHive: 90% cost reduction on small app
Small web app running on
AWS using a public cloud application
moved to AWS
Lambda
application fully
managed by Ec2
and ELB

HeavyWater: from 30,000$/mo to 3700$/mo
HeavyWater processes
files in batch using AWS
1000 Ec2 machines
200 Ec2
machines
39M AWS
Lambda
invocations

Serverless Cons
● (Still) hard to observe
● Cold Starts*
● Hard to hire knowledgeable developers
○ ecosystem is very new
● Each platform has specific tools
○ No common tooling
● Heavier reliance on vendor ecosystems

Public or Installable?
Public over Installable:
● Free below free tier
○ i.e. AWS Lambda has 1M requests/mo for free
● No ops team required
● Integrated within each cloud
○ i.e. a cloudwatch event can trigger an AWS Lambda
call

Public or Installable?
Installable over Public:
● Can be much more performant if properly configured
● Functions can be as big as you like* and run for as
long as you like
● Can be much cheaper on large scale (back of the
envelope
● Can run without the internet
*: within available resources

Source: CNCF Serverless WG Our Focus

Overview of (some) open source
serverless frameworks

● Creator: Alex Ellis, launched at DockerCon17
● Github stars: 12,100
● Start Date: Dec 18, 2016
● Contributors: 83
● Runs on Kubernetes and Swarm

RESTful
entrypoint
(CLI/API/WEB)
Metrics
Entrypoint
for function
process
Orchestrator

OpenFaaS example: authentication
package function
import (
"encoding/json"
)
func Handle(req []byte) string {
var e CloudEvent
if err := json.Unmarshal(req, &e); err != nil {
panic(err)
}
return "authentication successful"
}
return "authentication failed"
}
provider:
name: faas
gateway: http://12.123.123.123:33000
functions:
simple-auth:
lang: go
handler: ./simple-auth
image: julestestard/simpleauth

DTR
Docker
Hub
1. faas-cli build
2. faas-cli push
function
3. faas-cli deploy
function
4. faas-cli invoke
function
Native Tooling: faas-cli

● Github stars: 2,300
● Starte Date: Jun 4, 2017
● Focuses on data processing and
performance
● Runs on Kubernetes
● Sponsored by Iguazio

Pod
Creates function artifact
(runs in CLI context)
Kubernetes deployment
Kubernetes deployment

Nuclio example: authentication
package main
import (
"encoding/json"
"github.com/nuclio/nuclio-sdk-go"
)
func Handler(context *nuclio.Context, event nuclio.Event) (interface{}, error) {
var e CloudEvent
if err := json.Unmarshal(event.GetBody(), &e); err != nil {
return nil, err
}
return "authentication successful", nil
}
return "authentication denied", nil
}
relies on nuclio SDK

Any host
nuctl build
processor-simple-auth
image

apiVersion:
"nuclio.io/v1"
kind: Function
metadata:
name: simple-auth
namespace: nuclio
spec:
runtime: golang
handler: main:Handler
minReplicas: 0
maxReplicas: 10
Any host
nuctl deploy
Function CRD

Knative
● Kubernetes-based platform to build, deploy,
and manage modern serverless workloads.
● Release Date: Jun 4, 2018 (currently at v0.2)
● Runs on Kubernetes
● Sponsored by Google, Pivotal, IBM, Red Hat,
and SAP

Knative
Function developers
Function framework
maintainers

DTR
Docker
Hub
1. faas-cli build
2. faas-cli push
function
Istio
Envoy

Istio
apiVersion: serving.knative.dev/v1alpha1
kind: Service
metadata:
name: knative-hello-world
namespace: default
spec:
runLatest:
configuration:
revisionTemplate:
spec:
container:
image: julestestard/hello-world-http
kube api
server
Envoy5. curl -v -X POST
-d $data -H "Host:
knative-hello-world-
openfaas.default.ex
ample.com"
http://...
4. deploy knative
serving
kubectl apply
serving.knative
service
kube deployment
for function
replicas=0
knative hello-world pod
kube deployment
for function
replicas=3

Tools which will influence the future of FaaS:
- CloudFlare isolates
- AWS FireCracker
- Pulumi
New Trends

CloudFlare Isolates
● All functions which use the same runtime will use the same process
● Node JS runtime overhead: 35MB
● Node JS runtime using CloudFlag isolates: 3MB

AWS Firecracker
● Open Source Project
● Designed for multi-tenant function
services
● MicroVM: lightweight virtual machine
● Same hardware-virtualization-based
security as VMs
● Almost as fast to start as a container

Pulumi
Cloud Native Infrastructure as Code on any cloud with real
programming languages

Thank you!
Jules Testard
Install OpenFaas, Nuclio and Knative
on Docker EE and code samples

DCEU 18: Docker Containers in a Serverless World

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DCEU 18: Docker Containers in a Serverless World