Deep dive into the basics of Kubernetes Operators . Talk given at Docker Meetup - Bangalore.

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