Serverless apps with OpenWhisk

Serverless apps
with OpenWhisk
Cloud native • Event driven • Microservices
@DanielKrook • Senior Software Engineer • IBM Cloud
OpenWhisk.org

@DanielKrookOpenWhisk.org
What you will learn today
• How cloud has evolved to enable developers to write cloud native
applications better, faster, and cheaper using serverless technology.
• How OpenWhisk provides an open source platform to enable cloud
native, serverless, event driven applications.
• How to get started developing with OpenWhisk on Bluemix, or
contributing to the underlying open source serverless platform.

OpenWhisk.org @DanielKrook
What makes serverless,
event driven computing
so compelling?

Cloud evolution means developers can write apps better, faster, and cheaper
Bare
metal
Virtual
machines
Containers
Functions
Decreasing concern (and control) over stack implementation
Increasing focus on business logic

Newer workloads are a better fit for event driven programming
Execute app logic in response to database triggers
Execute app logic in response to sensor data
Execute app logic in response to cognitive trends
Execute app logic in response to scheduled tasks
Provide easy server-side backend for mobile app

Problem: It’s expensive to scale microservices
Explosion in number of
containers / processes:
1. Increase of infrastructure
cost footprint
2. Increase of operational
management cost and
complexity
Region BRegion A
Break-down into microservices
Make each micro service HA
Protect against regional outages
Monolithic application

Serverless can handle many cloud native app 12 Factors
I Codebase Handled by developer (Manage versioning of functions on their own)
II Dependencies Handled by developer, facilitated by serverless platform (Runtimes and packages)
III Config Handled by platform (Environment variables or injected event parameters)
IV Backing services Handled by platform (Connection information injected as event parameters)
V Build, release, run Handled by platform (Deployed resources are immutable and internally versioned)
VI Processes Handled by platform (Single stateless containers often used)
VII Port binding Handled by platform (Actions or functions are automatically discovered)
VIII Concurrency Handled by platform (Process model is hidden and scales in response to demand)
IX Disposability Handled by platform (Lifecycle is hidden from the user, fast startup and elastic scale is prioritized)
X Dev/prod parity Handled by developer (The developer is the deployer. Scope of what differs is narrower)
XI Logs Handled by platform (Developer writes to console.log, platform handles log streaming)
XII Admin processes Handled by developer (No distinction between one off processes and long running)

Problem: Programming and pricing models aren’t efficient
Continuous polling needed in the absence
of an event driven programming model
Charged for resources, even when idle
Worries persist about capacity management
Swif
t
Application
Container VMCF
2
Polling
1b
Request
1a

Cost model offers a better match between app and resources
Applications charged by compute
time (millisecond) rather than
reserved memory (GB/hour).
While many applications must still be deployed in a daemon
model, serverless provides an alternative that can mean
substantial cost savings for a variety of event driven workloads.
Greater linkage between cloud
resources used and business
operations executed.

Technological and business factors make serverless compelling
Serverless platforms and frameworks are gaining traction
Cost models getting more granular and efficient
Growth of event driven workloads that need automated scale
Platforms evolving to facilitate cloud native design for developers

Introducing
OpenWhisk

OpenWhisk in a nutshell
OpenWhisk is a cloud platform
that executes code
in response to events
OpenWhisk

OpenWhisk is different than other hosted services
Serverless deployment and operations model
Optimized utilization, fine grained metering at any scale
Flexible programming model with powerful tooling
Open source and open ecosystem (moving to Apache)
Ability to run in public, private, and hybrid models
OpenWhisk

OpenWhisk supports many growing workloads
OpenWhisk can help power
various mobile, web and IoT app
use cases by simplifying the
programming model of
orchestrating various services
using events without a dedicated
backend.
Digital app workloads Big Data/Analytics pipeline
Complex data pipelines for Big
Data/Analytics tasks can be scripted
using changes in data services or
streams for near real-time analytics
and feedback.
DevOps and infrastructure as code
OpenWhisk can be used to
automate DevOps pipelines
based on events triggered from
successful builds, or completed
staging, or a go-live event.
Microservices builder
OpenWhisk can be used to easily
build microservices given the
footprint and programming model
desired by microservices

The OpenWhisk
programming model

Triggers, actions, rules (and packages)
Data sources define the events they emit as triggers.
Developers associate actions to handle the events via rules.
T A R

Triggers
A class of events that can occurT
Social events
Data changes
Device readings Location updates
User input

Actions
Code that runs in response to an event
(that is, an event handler)
A

Actions
Can be written in a variety of languages, such as
JavaScript, Python, Java, and Swift
A
function main(params) {
return { message: 'Hello, ' + params.name + ' from ' + params.place };
};

Actions
Or any other language by packaging with DockerA

Actions
Can be composed to create sequences
that increase flexibility and foster reuse
A
AA := A1 + A2 + A3
AB := A2 + A1 + A3
AC := A3 + A1 + A2

Rules
An association of a trigger to an action
in a many to many mapping.
R
R := T A

Packages
A shared collection of triggers and actionsP
A
A read
write
T changes A translate A forecast
A post
T topic
Open
Source A myAction
T myFeed
Yours
T commit
Third
Party

OpenWhisk
in action

The OpenWhisk execution model
Pool of actions
Swift DockerJS
Trigger
1
Running
action
Running
action
Running
action
3
OpenWhisk
Engine
2 A
T
AAA

Demo 1: Create a
timer triggered action

Demo 1: Timer triggered action
Trigger
1
Running
action
2
T
A
Cron syntax alarm
Log the current time
$ wsk action create handler handler.js
$ wsk action invoke --blocking handler
$ wsk trigger create every-20-seconds
--feed /whisk.system/alarms/alarm
--param cron “*/20 * * * * *”
$ wsk rule create --enable
invoke-periodically
every-20-seconds
handler
$ wsk activation poll
bit.ly/ow-demo-1

OpenWhisk enables event driven applications
Event
Providers
Cloudant
GitHub
Weather
…
Which triggers execution of
associated OpenWhisk action
2
Slack
JS Swift Docker …
An event occurs, for example
• Commit pushed to GitHub repository
• Data changed in Cloudant
1
OpenWhisk

OpenWhisk can implement REST microservices
Send HTTP request
HTTP GET
app.com/customers
1
Invoke OpenWhisk
action get-customers
Browser
Mobile App
Web App
2
JS Swift Docker …
OpenWhisk
API
Proxy

Demo 2: Create
a Slack bot

Demo 2: Create a Slack bot
bit.ly/ow-demo-2
GET /register
POST /command
POST /event
Register
action
Event
action
Command
action
2
OpenWhisk
Engine
1
AAA
API
Proxy
Register
the bot
Respond
to direct
messages
Respond
to slash
commands

OpenWhisk
high level
implementation
architecture

OpenWhisk design principles
1. Provide an open interface for event providers
2. Offer polyglot support and simple extensibility for new runtimes
3. Support higher level constructs as appropriate (e.g. action sequences)
4. Scale dynamically on a per request basis
5. Enable sharing of actions and event providers
6. Leverage best of breed open source software (Docker, Kafka, Consul, …)
7. Use the Apache 2 License

OpenWhisk under the hood: Developer view
Couch
DB
Consul
Router (NGINX)
Controller
Kafka
Invoker Invoker
Docker
Executor Executor
Docker
Java Swift
Executor Executor
NodeJS Python
1. Router receives request to API
via CLI or UI
2. Controller checks entitlement and
dispatches requests to Kafka
3. Invokers pull requests from
CouchDB and start execution of
the action

OpenWhisk under the hood: A deeper look
bit.ly/ow-int
1. Entering the system: nginx
2. Really entering the system: Controller
3. Authentication and Authorization: CouchDB
4. Getting the action: CouchDB… again
5. Who’s there to invoke the action: Consul
6. Please form a line: Kafka
7. Actually invoking the code already: Invoker
8. Storing the results: Yes… CouchDB again

OpenWhisk container model
Philippe Suter
bit.ly/ow-psuter

OpenWhisk container model

Summary

What you learned today
• We’re in the early days of an evolution that is empowering
developers to write cloud native applications better, faster, and
cheaper
• OpenWhisk provides an open source platform to enable cloud
native, serverless, event driven applications
• Bluemix provides a hosted instance of OpenWhisk that you can
use to get started (and offers integration with a catalog of services)

Experiment with OpenWhisk on Bluemix
bit.ly/ow-bm

Join us to build a cloud native platform for the future!
OpenWhisk.org
dwopen.slack.com #openwhisk
bluemix.net

Backup

Watson IOT OpenWhisk
Customer
registry
Shipping
system
SendGrid
Service
reports
actions
IBM Cloud
LOB, SoR
systems &
databases
Need a
new filter
Email: Filter
on its way!
bit.ly/open-fridge

analyze
reading
OpenWhisk
create
order
alert
customer
alarm
changes changes
service order appliance
feed
Watson
IoT
A A AT
T T
T
P
P
P
bit.ly/open-fridge

OpenWhisk CLI: Create and test action
Create the Action that analyzes IoT readings, then stores in the database
wsk action create analyze-service-event analyze-service-event.js
--param cloudant_user $CLOUDANT_USER
--param cloudant_pass $CLOUDANT_PASS
Invoke the Action manually with sample message data to test
wsk action invoke --blocking --result analyze-service-event
--param service '{"appliance_serial": "xxxxyyyyzzzz", "part_number":
"ddddeeeeffff", "reading": 13, "timestamp": 1466188262}'
A

OpenWhisk CLI: Link trigger to action
Create the Trigger that subscribes to an MQTT topic pattern
wsk trigger create openfridge-feed-trigger
--feed mqtt/mqtt-feed-action
--param topic 'iot-2/type/+/id/+/evt/+/fmt/json'
--param url 'ssl://example.messaging.internetofthings.ibmcloud.com:8883’
Link the Trigger to the Action using a Rule
wsk rule create --enable openfridge-feed-rule
openfridge-feed-trigger analyze-service-event
R := T A

Serverless apps with OpenWhisk

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