The document discusses Kubernetes operators and provides an overview of a Drupal operator called Druperator that is being developed by Srijan. It summarizes Kubernetes operators, how they automate application lifecycles on Kubernetes. It then discusses extending the Kubernetes control plane through custom resource definitions and controllers. Finally, it mentions that Druperator is a custom controller for managing the lifecycle of Drupal applications on Kubernetes.

1. Kubernetes Operators
Druperator - Drupal Operator
Adheip Singh | Senior DevOps | Srijan
#SrijanWW | @srijan

2. ⏩ Hybrid Cloud
⏩ API Economy
⏩ Cloud Native
⏩ Big Data
⏩ DevOps
SRIJAN is a full stack, full lifecycle digital engineering
firm.
We specialize in platform & product innovation, utilizing
the best in class polyglot tech stack, open source
frameworks & (almost any) cloud infrastructure.
Our customers say we run software delivery like a
hospitality business.
● Product Engineering
● Enterprise Content
Management
● Learning Ecosystems
● Omnichannel Media
● Analytics
● Machine Learning
● Data Engineering
● Intelligent Automation
➔ 16+ years of profitable growth
➔ 10+ multi-year enterprise customers
➔ 15+ global offices across 10 countries in 4 continents
➔ 350+ employees and growing, across 3 service lines
Digital Experience Platform Modernization Data Intelligence

3. #SrijanWW | @srijan
This session is relevant for you if
you are:
● An IT / Business stakeholder responsible
for the development and operations of Drupal
project on k8s.
● An infrastructure or cloud engineer curious
to gain a worldview around running
Kubernetes
● A developer / application engineer who
wants to run application workloads
seamlessly on k8s.
● A Drupal Company / Managed Services Org
that builds (OR) maintains a number of Drupal
sites.
About this session
What you will learn during this session:
● Gotchas around “running” Kubernetes
Operators
● Def:
○ “Platform”
○ “Cloud Native”
● LAMP stack Gotchas
○ On Docker Containers
○ Kubernetes (a full refresher)
● How to build and run your own

4. #SrijanWW | @srijan
● Formerly a Content Management System with D8 -
Evolved to a Symfony-esque Content Management
Framework
● Amongst the most popular OSS projects in the world:
Active community of 100K+ contributors with a plugin
ecosystem of 40K+
● Powers a whole range of web applications in diverse
domains: Gov, Media/Entertainment, Education,
Publishing, Nonprofits Consumer Internet unto high
tech
● Mature ecosystem of service providers:
Single-person studios to SIs with whole units focussed
on Drupal development
A quick recap on Drupal

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● Docker: de-facto standard for containers. Tiny
footprint vis-a-vis conventional VMs. Shared
kernel and separated user space
● Kubernetes: de-facto standard for container
orchestration (born at Google)
● Containers needs management plus distributed
systems is a problem
● Kubernetes helps to manage lifecycle of
containers, distribution, scheduling, command &
control, etc
● Together: de-facto standard for cloud
abstraction. Ability to run on any cloud without
binding to IaaS primitives
Introduction To Kubernetes

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KUBERNETES ARCHITECTURE

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● Operators are softwares written to encapsulate all of those operational considerations for a
specific Kubernetes application.
● Operators ensure that all aspects of an application lifecycle starting from configuration and
deployment to upgrades, monitoring, and failure-handling, are integrated right into the
Kubernetes framework and invoked when needed.
● Capability levels of an Operator :--
○ An operator ensures Basic Install of an Application in an automated way which is
usually a single spec file.
○ Operator offers seamless upgrades.
○ Full Application Lifecycle.
○ Auto Pilot Mode. Deploy and sit back.
Kubernetes Operators

8. #SrijanWW | @srijan
Let’s Extend the Kubernetes Control Plane

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● Kubernetes provides various ways to extend its control
plane :--
○ Custom API Server
○ Custom Resource Definitions CRD’s.
○ Custom Schedulers
○ Webhooks ( Admission Control Plugins )
○ Kubernetes 1.11 provides a way of adding custom
cloud controller manager process to integrate with
the Cloud.
○ Kublet Plugins
How to extend Kubernetes Plane

10. #SrijanWW | @srijan
● CRD’s are available in every kubernetes cluster since version 1.7.
● Custom Resources are stored in the same etcd as the main K8s resources.
● The kubernetes API creates a new REST path for the CR.
● CRD’s have a scope, they can be namespaced or cluster scoped.
● Validation of a CRD takes place through OpenAPI Scheme. Current version is v3.
● Each Custom Resource has a
○ Group -- srijan.net
○ Version -- v1 alpha1
○ Kind. -- druperator
Custom Resource Definition

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Custom Controllers or Operators ?

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● In order to write operators SDK’s are available for scaffolding and helping you focus
primarily on the reconcile loop.
● Provides high level API’s, Useful abstractions and project scaffolding
● Extensions to cover common operator use cases.
● Some popular SDK’s widely used are :-
1. Operator-SDK
2. Kube-Builder
3. MetaController
Getting Started With Operators Using
SDK’s

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SDK or No SDK

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● Though SDK’s can help you get started quickly but due to high level abstractions,
boilerplate code which can be cause for multiple bugs and low level production grade code.
● In order to write controllers from scratch one must have understanding of client libraries
and kubernetes controllers as in whole.
● Tools like code-gen can be useful and timesaving in generating Listeners, Watchers and
writing DeepCopy Functions.
● Client Libraries are available in :--
○ Golang
○ Java
○ Python
○ Rust
Writing Operators From Scratch

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Custom Controller Architecture

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● At Srijan we are building a Drupal Operator (Druperartor), which is an operator for
managing drupal application lifecycle on kubernetes.
● Currently the operator is in pre-alpha stages of development.
● Druperator is a custom controller for watching druperator resources as defined with a
Custom Resource Definition(CRD).
● Druperator code will be open sourced once development proceeds to beta stage.
Druperator - Drupal Operator For
Kubernetes

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Demo