2. Kubernetes
and the Rise of
Application-centric Computing
Angus Lees <gus@bitnami.com>

3. Why

4. The Software Stack
Your Code
Framework
Language
Software Distribution
OS/Kernel
CPU
Physical Enclosure
Electricity/Cooling

5. Maturity CurveRisk
Novelty
ExperimentationCommoditisation Maturation
Open-Source dominates here
Businesses want to be here

6. Maturity CurveRisk
Novelty
Niche/CrazyBoring Interesting

7. The Server-Side Software Stack
Your Code
Framework
Language
Software Distribution
OS/Kernel
CPU
Physical Enclosure
Electricity/Cooling
Boring infrastructure
Interesting 3rd-party
choices
Your actual problem
Somewhere here

8. Introducing Kubernetes
• Cluster orchestrator/manager
• Often abbreviated to “k8s”
• Runs jobs in containers (usually Docker images) - no VM overhead
• Originally created/released by Google based on internal experience
• Vibrant Free Software project (Apache2 license)
• Application-centric focus

9. Application-centric
You tell Kubernetes:
• Application executable, required libraries (as a docker image)
• Command line arguments, environment variables
• Config files
• Application health checks
• (Optionally) memory/cpu requirements, scheduling hints
... and Kubernetes does everything else

10. … with Kubernetes + Docker
Your Code
Framework
Language
Software Distribution
OS/Kernel
CPU
Physical Enclosure
Electricity/Cooling
Boring infrastructure
Interesting 3rd-party
choices
Your actual problem
Somewhere here

11. Application-Centric Computing
Before: After Kubernetes+Docker:
✓ Where to run
✓ How to run
✓ How to upgrade
✓ Recovering from failures
Interesting: Orchestration
Boring: Hardware
Interesting: Applications
Boring: Everything else

12. Kubernetes
Now boring is “how”, and
interesting is “what”

13. What

14. Declarative Configuration
• Say what not how
• Install/upgrade/downgrade is
all derived from single config
• Allows for strong tooling
ecosystem
• No mention of host details,
VMs, network topology, etc
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: frontend
spec:
replicas: 3
template:
metadata:
labels:
app: guestbook
tier: frontend
spec:
containers:
- name: php-redis
image: gcr.io/google-samples/gb-frontend:v4
resources:
requests:
cpu: 100m
memory: 100Mi
env:
- name: GET_HOSTS_FROM
value: dns
ports:
- containerPort: 80

15. Building Blocks
Most common:
• Pod - group of containers that always run together
• Deployment - describes a number of replicas of a pod
• Service - exposes several pods as a single load-balanced entity
• PersistentVolume - abstraction over network attached storage
• ConfigMap - configuration made available to pods
• Secret - like ConfigMap, but assumed to contain sensitive material

16. Internal Architecture

17. … with Kubernetes + Docker
Your Code
Framework
Language
Software Distribution
OS/Kernel
CPU
Physical Enclosure
Electricity/Cooling
Boring infrastructure
Interesting 3rd-party
choices
Your actual problem
Somewhere here

18. Functions aim to be general purpose infrastructure, unlike PaaS.
Functions raise the level of “boring”, into your application.
#!Boring
boring(boring)
boring
# Boring boring
boring boring(boring):
--> Your code goes here <--
Boring(boring) -> boring;
boring {{boring.boring}}
Next? Functions as a Service

19. Highlight: Kubeless
• Kubernetes native - designed specifically for Kubernetes
• Simple - reuses existing Kubernetes pieces wherever possible
• Node.js, Python, Ruby and more on the way
• Open Source project, led by Bitnami
• Get prometheus metrics, error handling, etc for free from runtime,
you just provide the “do work” function

20. Example: Automatic Thumbnail Creation
#!python
# (Some imports and global variable declarations elided)
def thumbnail(context):
bucket = os.path.dirname(context['Key'])
_, file_extension = os.path.splitext(context['Key'])
filename = os.path.basename(context['Key'])
if file_extension.upper() != ".JPEG":
return "Not a picture"
if context['EventType'] == "s3:ObjectCreated:Put" and bucket == 'foobar':
tf = tempfile.NamedTemporaryFile()
tf_thumb = tempfile.NamedTemporaryFile()
client.fget_object(bucket, filename, tf.name)
img = Image.open(tf.name)
img.thumbnail((120,120))
img.save(tf_thumb.name, "JPEG")
# puts the thumbnail in a thumbnail bucket
client.fput_object('thumb', thumb_name = filename + '.thumb', tf_thumb.name)
return "Thumbnail creation triggered"

21. Minio (an object store) configured to send notifications to kafka pubsub.
Install function:
% kubeless function deploy thumb1
--trigger-topic s3
--runtime python2.7
--handler resize.thumbnail
--from-file resize.py
--dependencies requirements.txt
Done.
Example: Automatic Thumbnail Creation

22. kubeless-ui

23. Behind the scenes, Kubeless builds:
Example: Automatic Thumbnail Creation
Function
ThirdParty
Resource
Service
(for HTTP
triggers)
ConfigMap
Deployment
kubeless
client or
kubectl
Code
Code

24. https://kubernetes.io
Local Kubernetes experiments: minikube
Kubernetes on Oracle Cloud Platform How-To:
https://docs.bitnami.com/kubernetes/how-to/set-kubernetes-cluster-oracle/
http://kubeless.io/
Next Steps

25. Thank You