Containers aren't just for stateless apps. You might have mission-critical stateful applications like MySQL, Kafka, or Cassandra databases that you want to run in containers as well. Sahil Sawhney gave an overview on how both; stateless and stateful services could be deployed over Kubernetes with ease thus reducing the service management efforts and making the scaling more manageable. This pdf walks you through, the application of Stateful Sets and Operators and how they work internally to ensure state maintenance over the K8 cluster

1. Being Stateful In Kubernetes
Presented By : Sahil Sawhney
Sr. Software Consultant
@lihas5

2. Agenda
In this session we will explore how feasible it is to deploy a
stateful services over Kubernetes.
Introduction
Knowing Kubernetes
Types Of Services
Understanding stateful and stateless services
Stateful Sets And Operators
Knowing how to deploy a stateful Service
Case Study With Demo
Lets See Things Rolling

3. Kubernetes, The Buzz
Kubernetes is a production grade open source
orchestration system used to deploy, scale and
manage containerised applications. It is based on the
same principles that allow Google to run billions of
containers a week.
Container Platform
With Kubernetes you can
orchestrate your fleet of
containers with ease.
Microservices Platform
K8 could also be used as a
platform for deploying your
microservice architecture
Portable Cloud Platform
K8 as a platform makes it
easier to deploy, scale,
and manage apps

4. Service Types
Stateless Applications
Single-Instance Stateful Application
Replicated Stateful Application
Nginx, My Play/Akka-Http Application
or any other stateless Microservice.
My single node mysql with a
persistent volume.
Use a StatefulSet to create a
Cassandra ring.

5. Comparing Our Protagonists
services applies operations on the input
data and produces an output. Fos same
set of inputs, the output will always be
same.
Stateless
means the system can be in different
states ie. The same input can produce
different output based on other
information in the system
Stateful

6. Once Upon A Time ...
The classic containerized approach of deploying a
microservice architecture meant this :
Spark
I am a processing engine. My mistake is that
i sometimes I do stateful operations.
Kafka
I am a message queue. My mistake is that I
persist the inter service comm. messages.
Cassandra
I am a NOSQL Db. My mistake is that I can
scale easily on bare metals.
Elasticsearch
Hang me please …..

7. Kubernetes is not just a platform to run your containers. It provides various other rich
features like network management and persistent storage which could be exploited so
as to deploy your microservice architecture that follow Reactive Manifesto:
But Isn't Kubernetes All About Containers
?

8. The Saviour
StatefulSets are valuable for applications that
require one or more of the following.
Stable, unique network identifiers.
Graceful deployment and scaling.
automated rolling updates.
Stable, persistent storage.
Use Case
Used majorly to deploy stateful
services like
1). Databases (Mysql, MongoDB, ES)
2). Queues (Kafka)
Many more ...
Stateful Sets

9. Demonstration

10. Noida, NSEZ
+919871211045
sahil.sawhney.10
@lihas5
Thank You!
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