This document discusses Kubernetes operators and provides an overview of their purpose and components. Operators allow developers to focus on business logic and desired application configuration rather than manual deployment and lifecycle management details. Operators extend the Kubernetes API through custom resources and custom controllers. Custom resources define the desired state and custom controllers work to keep the current state in sync with the desired state. Operators automate common tasks like scaling, upgrading, and reconfiguring stateful applications while protecting data.

1. Demystifying K8s Operators
Docker Meetup – Dell EMC

2. $whoami
 Suman Chakraborty - Sr. Devops
Platform Engineer @SAP Labs
 Community member @Docker
Bangalore, Collabnix
 Tech Blogger mostly on PaaS &
Opensource stuffs
https://www.linkedin.com/in/
schakraborty007/
@suman123

3. Kubernetes 101
 Open source platform for managing, orchestrating and deploying
container workloads.
 Google open source (Borg)- 2014, name originated from helmsman or
pilot
 Ensures scalability and separation of workloads.
 Distributed architecture with clear segregation of control plane and data
plane
 Application management through native stable resources (pods,
deployments, replicasets, services)
 Allows extending the API through custom resource defintions.

4. ‘Stateless’ vs ‘Stateful’
Stateless is EASY !!!
$ kubectl scale deployment web --replicas=3
Deployment
app=web, env=prod
Pod
app=web, env=prod
Scale Out
desired =3 count =1
start
count =3

5. Stateful is hard !!!
 Stateful applications require application domain knowledge to
correctly scale, upgrade and reconfigure while protecting data loss
or unavailability.
eg – distributed database, caches and monitoring systems.
 Needs stable persistent storage. Requires application specific
notion of clustering and interconnectivity.
 Requires coordination for authentication and authorization of
cluster members.
 Coordination is again needed during resizing and upgrading.
 Needs backup and lifecycle management operations.

6. Kubernetes Operators ~ the Savior !!!
 “An Operator is a method of packaging, deploying and managing a
Kubernetes application” – CoreOS
 Extends the Kubernetes API to enable management of multiple
instances of a complex stateful application.
 Leverages powerful Kubernetes extraction of resources and
controllers by including domain-specific knowledge to automate
common tasks.
Operators allow developers to focus on business logic on the desired
configuration , not the details of manual deployment and lifecycle
management

7. Components of an Operator
 Custom Resources :
 Custom resource is an extension of the Kubernetes API that is not
necessarily available in a default Kubernetes installation.
 Created through dynamic registration and perform CRUD operation.
 Managed independently of the cluster itself using ‘kubectl’ as
managed for Kubernetes resources.
apiVersion: mysql.oracle.com/v1
kind: MySQLCluster
metadata:
name: my-db-cluster
spec:
replicas: 3
multiMaster: true

8. Components of
an Operator
 Custom Controllers :
 Controller uses a ‘declarative API’ to
declare or specify the desired state of
the resource and tries to keep the
current state of Kubernetes objects in
sync with the desired state.
 Controllers can be updated
independent of cluster own lifecycle.

9. 101 ways to build an operator
 go language :
• client-go & co.
• operator-sdk
• KUDO (Kubernetes Universal Declarative Operator)
• kubebuilder
 Other languages :
• kubernetes python and java clients and others
 Other tools:
• helm
• ansible

10. Operator Framework
Build: Enables developers
to build Operators based on
their expertise without
requiring knowledge of
Kubernetes API complexities
Run: Oversees installation,
updates and management
of the lifecycle of all of the
Operators
Operate (beta phase): Enables
usage reporting for Operators
that provide specialized
services.
Lifecycle Manager Operation

11. https://operatorhub.io/

13. THANK YOU