Kubernetes for FaaS (Function as a Service) - Serverless evolution, some basic constructs, kubenetes features, comparisons - from Serverless conference 2017 Bangalore.

1. Why Kubernetes for Serverless?
by Krishna Kumar, Huawei India
CNCF Ambassador

2. Content
Evolution of Serverless world
& then…
Kubernetes Features towards Serverless…..

3. Containers – The History Highlights
1979
UNIX
chroot
provide an
isolated disk
space for each
process. Later in
1982 this was
added to BSD
FreeBSD
Jails
additional
process
sandboxing
features for
isolating the
filesystem, users,
networking, etc
2000 2001
Linux
VServer
securely partition
resources on a
computer system
(file system, CPU
time, network
addresses and
memory)
2004
Solaris
Containers
combination of
system resource
controls and the
boundary
separation
provided by
zones
2005
OpenVZ
isolated file
system, users
and user groups,
a process tree,
network, devices,
and IPC objects.
2006
Process
Containers
limiting,
accounting, and
isolating resource
usage (CPU,
memory, disk I/O,
network, etc.) of a
collection of
processes
2007
Control
Groups
Control Groups AKA
cgroups was
implemented by
Google and added to
the Linux Kernel in
2007
2011
Warden
Warden was
implemented by
CloudFoundry in
year 2011 by
using LXC at the
initial stage
2013
LMCTFY
lmctfy stands for
“Let Me Contain
That For You”. It is
the open source
version of Google’s
container stack
LXC
LXC stands for
LinuX Containers
and it is the first,
most complete
implementation of
Linux container
manager
2008 2013
Docker
Docker is the
most popular and
widely used
container
management
system as of
January 2016
2014
Rocket
Rocket is a much
similar initiative to
Docker started by
CoreOS for fixing
some of the
drawbacks
2016
Windows
Containers
Run Docker
containers on
Windows natively
without having to
run a virtual
machine to run
Docker

4. Virtual Machines, Containers and Unikernels

5. Evolution of Applications Development
MainFrame Client/Server SOA MSA Serverless

6. Serverless Evolution
2014-11 2015-10 2016-01 2016-2 2016-4 2016-5
Serverless
2016-6
OpenLambda
2016-7
DC/OS serverlessApcera
AWS Lambda
2016-3

8. https://www.cncf.io/

9. Serverless From BIG Players
• AWS lambda - https://aws.amazon.com/lambda/
• Azure Functions - https://azure.microsoft.com/en-in/services/functions/
• Google Cloud Functions - https://cloud.google.com/functions/
• IBM OpenWhisk - https://www.ibm.com/cloud-computing/bluemix/openwhisk
• Oracle Fn - https://blogs.oracle.com/emeapartnerweblogic/serverless-architecture-on-the-oracle-
paas-cloud-by-lucas-jellema

10. Serverless Implementations - Others
 Fission.io (https://github.com/fission/fission)
 Kubeless (https://github.com/bitnami/kubeless)
 Iron Functions (https://github.com/iron-io/functions)
 Fabric8’s (https://github.com/funktionio/funktion)
 Alex’s (https://github.com/alexellis/faas) (Use Docker Swarm)
 Galactic fog (https://github.com/GalacticFog)
 Ovrclk.com (not open source)
 Lightbend - www.lightbend.com
 Iceroad www.iceroad.io
 AuthO Webtasks - https://auth0.com/blog/building-serverless-apps-with-webtask/

11. https://github.com/anaibol/awesome-serverless

12. A Severless Architecture (Amazon Lambda)

13. Severless Architecture Benefits & Drawback
(From AWS)

14. Serverless is misnormal…...
It is Functions as a Service (FaaS)

15. Why Kubernetes for FaaS?

16. Kubernetes Orchestration Engine1
Setup
• On Cloud infrastructure
• Google
• AWS
• Azure
• IBM Blue Mix
• On local machine
• MiniKube
• Ubuntu on LXD
• Kubeadm
• IBM Cloud Private CE

17. Kubernetes – AutoScale with custom metrics
• With Horizontal Pod Autoscaling, Kubernetes
automatically scales the number of pods in a replication
controller, deployment or replica set based on observed
CPU utilization (or, with custom metrics support, on
some other application-provided metrics).
• Needs Heapster and Cadvisor (already a part of
Kubernetes)
• Resource Metric Source (CPU or Memory). Per-pod
resource metrics (like CPU),
• The key operational difference between FaaS and PaaS
is scaling. With most PaaS’s you still need to think about
scale.
• FaaS needs infrastructure and k8s supports that well.
From Function it creates services and manage its life
cycle.
• https://kubernetes.io/docs/tasks/run-
application/horizontal-pod-autoscale/
2

18. Kubernetes – Workloads
• StatefulSet - Stateful Application that needs reasonable handling
• Like Database
• In-memory Cache
• Peer – Peer applications that needs
storage
• Any application that needs network
identity
• Stateless - For stateless application to deal with complex workflow
• Like webservers
• Are stateless in nature that needs on-
demand scale
• Needs rolling update
• Jobs - Run once type of workloads
• Useful for running scripts, reports
and batch jobs
• Like DB-Query
• Like Spark / Hadoop processing
• CornJobs – Run once type of Jobs by repeat in a frequency
• Just like unix CornJob
• Runs a job at a given schedule
• DaemonSet – Run on all the Nodes as much as possible
• Runs in every node in the cluster.
• For starting monitoring applications
on every node.
• ReplicaSet – Run and manage multiple Pods lifecycle.
• Elementry Controller for managing
PODs
• Used by Deployment.
FaaS Workloads
• Time based processing/CRON job
• Time based recurring jobs, clean up etc.
• Event processing
• Servicing SaaS & cloud events like changes is
Storage, DB, etc. and to display it in graphical
way
• Web applications
• Single web page apps, that manage user
data store/display/customization.
• Mobile backend
• Mobile client can use HTTP APIs to
store/process, eg. Photos
• Real-time stream processing
• IoT devices can send messages for
stream analytics
• Real-time bot messaging
• Chat/Message bots
• Answer questions using AI (Cortana)
 FaaS functions are stateless. The ‘Twelve-
Factor App’ concept is also same.
3
12 factors
(solid
principle for
Cloud
Software
Architecture)
Codebase One codebase tracked in
revision control, many
deploys
Dependencies Explicitly declare and
isolate dependencies
Config Store configuration in
the environment
Backing Services Treat backing services as
attached resources
Build, release, run Strictly separate build
and run stages
Processes Execute the app as one
or more stateless
processes
Port binding Export services via port
binding
Concurrency Scale out via the process
model
Disposability Maximize robustness
with fast startup and
graceful shutdown
Dev/prod parity Keep development,
staging, and production
as similar as possible
Logs Treat logs as event
streams
Admin processes Run admin/management
tasks as one-off
processes
K8s Cloud Native and Serverless has same Workload Characteristics

19. Expose Service from Function4
 A Service in Kubernetes is an abstraction which defines a logical set of Pods and a
policy by which to access them.
 Services enable a loose coupling between dependent Pods. A Service is defined using
YAML (preferred) or JSON, like all Kubernetes objects.
 The set of Pods targeted by a Service is usually determined by a LabelSelector
 Although each Pod has a unique IP address, those IPs are not exposed outside the
cluster without a Service. Services allow your applications to receive traffic. Services
can be exposed in different ways by specifying a type in the ServiceSpec (ClusterIP,
NodePort, LoadBalancer, External Name)
 HTTP services from k8s from functions very easy to create.
 API based calls – deal with event handlers (notification from other services)
 Idle function only use storage and consume only CPU/memory when at use – trigger
fires.
Function can run at source level, or as buildpack or as docker images.
https://kubernetes.io/docs/tutorials/kubernetes-basics/expose-intro/

20. Associate functions with k8s watches, triggers, HTTP routes5
Watch resource from k8s API – Native integration with k8s
•POD problem
•Other events
•Do something
Create function and add them using CLI/etc.. Then associate functions with k8s watches, triggers, HTTP
routes.
Issue a watch request using normal http request - the API consumes and returns JSON messages.
Labels can be used to organize and to select subsets of objects. Labels can be attached to objects at
creation time and subsequently added and modified at any time.
Funktion – Apache Camel Connector (some thing happens do something)
Step Functions – One after another events. Call in sequence order.
https://stackoverflow.com/questions/35192712/kubernetes-watch-pod-events-with-api

21. Init Container6
A Pod can have multiple Containers
running apps within it, but it can also have
one or more Init Containers, which are
run before the app Containers are started.
Init Containers are exactly like regular
Containers, except:
•They always run to completion.
•Each one must complete successfully
before the next one is started. They all
must run to completion before the Pod
can be ready.
https://kubernetes.io/docs/concepts/workloads/pods/i
nit-containers/
Init Containers
Can be used for
- Sleep
- Register Pod
- Clone a git
- Place value to config file

22. Kuberntes Config Map7
Config map to inject function's code to the runtime pod.
The ConfigMap API resource provides mechanisms to inject
containers with configuration data while keeping containers
agnostic of Kubernetes
ConfigMaps allow you to decouple configuration artifacts
from image content to keep application portable.
ConfigMap is similar to Secrets, but provides a means of
working with strings that don’t contain sensitive
information
The ConfigMap’s data field contains the configuration data.
As shown in the example, this can be simple – like
individual properties defined using --from-literal – or
complex – like configuration files or JSON blobs defined
using --from-file. There is size limitations exists.
https://kubernetes.io/docs/tasks/configure-pod-
container/configmap/

23. Custom Resource Definitions (CRD) to simulate function's metadata8
From Kubeless documents (how they run):
•There is a CRD endpoint being deploy called function.k8s.io:
•Then function custom objects will be created under this CRD endpoint.
•function.spec contains function's metadata including code, handler, runtime, type (http or pubsub) and
probably its dependency file.
•Custom controller watch changes of function objects and react accordingly to deploy/delete K8S
deployment/svc/configmap. These containers fetch all the dependencies and share them with the function
runtimes using volumes.
•The runtimes are pre-built docker images that wrap the functions in an HTTP server or in a Kafka
consumer. Indeed, to be able to trigger functions via events we currently use Kafka.
•There are currently two type of functions supported in Kubeless: http-based and pubsub-based. A set of
Kafka and Zookeeper is installed into the kubeless namespace to handle the pubsub-based functions.
https://github.com/kubeless/kubeless/blob/master/docs/architecture.md
May be useful in some implementations………

24. Volume mount / storage for custom source load9
On-disk files in a container are ephemeral, which presents some problems for non-trivial
applications when running in containers. First, when a container crashes, kubelet will
restart it, but the files will be lost - the container starts with a clean state. Second, when
running containers together in a Pod it is often necessary to share files between those
containers. The Kubernetes Volume abstraction solves both of these problems.
https://kubernetes.io/docs/concepts/storage/volumes/
Runtime Source/Function

25. Everything is API Driven
Serverless Architecture
 Kubernetes is API Driven Model
 Functions in FaaS are triggered by event types defined by the
provider.
 Functions to be triggered as a response to inbound http requests,
typically in some kind of API gateway. (e.g. AWS API
Gateway, Webtask)
 Fundamentally FaaS is about running back end code without
managing your own server systems or your own server
applications. That is the key difference when comparing with other
modern architectural trends like containers and PaaS (Platform as a
Service.)
 FaaS is seen as a better choice for event driven style with few event
types per application component, and containers are seen as a better
choice for synchronous-request driven components with many entry
points.
 https://martinfowler.com/articles/serverless.html - Must read article!
10

26. Kubernetes properties for FaaS!
1) Automatic orchestration - Seemless Deployments of Install and remove.
2) Horizontal Autoscale - Custom metrics can be pulled out easily for scaling.
3) K8s Cloud Native and serverless has same Workload Characteristics.
4) Expose service from function - HTTP services from k8s functions very easy to create.
5) Associate functions with k8s watches, triggers, HTTP routes.
6) Init container to load the dependencies that function might have.
7) ConfigMap for runtime load.
8) Custom Resource Definitions (CRD) to simulate function's metadata.
9) Volume mount / storage for custom source load.
10)Everything Remote API Driven!

27. Fission on K8S
Put together you get - Kubernetes Serverless Architecture Models
Custom
Commercial
Deployments

28. Open Source Serverless comparison

29. Commercial Serverless Feature comparison
https://cloudacademy.com/blog/microsoft-azure-functions-vs-google-cloud-functions-fight-for-serverless-cloud-domination-continues/

31. Container Orchestration Comparison

32. Container Orchestration Comparison

33. https://apprenda.com/white-papers/container-orchestration-comparison-guide
Container Orchestration Comparison
Astonishing growth

34. Kubernetes still lead the pack
in comparison to other container orchestration!
Some of the materials used in this presentation are taken from web.
Its used here just for educational purpose only. Thanks to all for those wonderful contents.  
Thanks……