Stateful vs Stateless Applications in Kubernetes might be cliche in 2018. A host of advancements and projects in the K8’s ecosystem help bridge the gap. With the Product Owner’s dilemma, having to produce a K8’s deployable was one more distribution for an application.

1. July 2018
Call the Operator!
A little dabble into Kubernetes Operators and Operator SDK
Ravi Lachhman

2. Ravi Lachhman
● Technical Evangelist at AppDynamics.
● Prior experience at Mesosphere, Red
Hat, and IBM.
● Specialties include SQL and NoSQL DB
corruptions and not being able to do
CIDR calculations.
@ravilach

3. Stateful Applications in Docker?! [2014]
OR
@ravilach

4. Our Friend, the Technology Curve
https://blog.risingstack.com/the-history-of-kubernetes/ @ravilach

5. Our Friend, the Technology Curve
● MVP
● Describe your application in a deploy.yaml
@ravilach

6. Stateful Applications in Docker?! [2018]
OR
@ravilach

7. Product Owner’s Dilemma
https://deis.com/blog/2016/kubernetes-illustrated-guide/ @ravilach

8. Why the Operator?
● Steller example from Yellow Jacket, Neha Narkede, co-
founder of Confluent.
● Allows programmatic mappings and packaging of
application functionality to Kubernetes Primitives.
● Moving from describing applications in K8’s to building
applications to K8’s.
● https://www.confluent.io/blog/introducing-the-
confluent-operator-apache-kafka-on-kubernetes/
@ravilach

9. Wait, is this a CRD?!
● CRD is a Custom Resource Definition in the K8’s spec.
Next generation of “Third Party Resource” <1.8
● Custom endpoint which represents a custom K8’s
installation.
● Below setting up a CronTab via K8’s [CNF exam].
@ravilach

10. A Brief History of the Operator
● Created by CoreOS in late 2016
● Next rendition is the Operator SDK which was built in
conjunction with Red Hat in the first half of 2018; this is
a pre-alpha release.
● With the SDK, can start interfacing with low level API’s
and primitives with K8’s.
● Getting traction with platforms such as Kafka, etc.
@ravilach

11. +1 Controller
● A Controller is needed to manage resources, in this case
a Custom Resource.
● A Custom Controller needs to watch, react, and update
components.
● Get ready to write some GO!
● https://resources.coreos.com/youtube-coreos-fest-
2017/writing-a-custom-controller-extending-the-
functionality-of-your-cluster
@ravilach

12. Good Resources
● CoreOS Blog:
● https://coreos.com/blog/introducing-operators.html
● List of Operators
● https://github.com/operator-framework/awesome-
operators
● Building a Controller
● https://engineering.bitnami.com/articles/kubewatch-
an-example-of-kubernetes-custom-controller.html
● Controller Parts
● https://medium.com/@cloudark/kubernetes-custom-
controllers-b6c7d0668fdf
.
@ravilach

13. July 2018
Go and Operate (or Control)!
rlachhma@cicso.com
@ravilach