{Kubernetes}

- Developer 101 -
How to transition from ECS to K8s & Gitops

Florian Dambrine - Principal Engineer

From ECS to K8s - What has changed ?

CI/CD

1.

  • Changes in CI/CD
  • GitOps workflow

2.

Container Platform

  • Container Platform
  • Deployment Anatomy
  • Load balancing

3.

Tooling

  • CLI and Tools
  • ArgoCD
  • Logging
# Agenda

CI/CD Changes

Legacy Vs New Pipeline

GitOps Workflow

Kubernetes CI/CD Workflow

# Legacy ECS

CI - Build the application JAR and run checkstyle & unit tests

Deployment Api & Router - Active ECS deployment using ecs-cli (tight coupling)

Notification - Developer feedback on Slack

CD - Docker image build and registry push

# New K8s

CI - Build the application JAR and run checkstyle & unit tests

Deployment Api & Router - Auto Versioning + GitOps Workflow (passive / decoupled)

Notification - Developer feedback on Slack

CD - Docker image build and registry push

Principles
 

  • Ensure separation of concerns by decoupling the application code from its platform deployment (make use of two git repos)
     
  • Ensure propagation of a change to the live infrastructure in an automated fashion (eg. new docker image pushed to registry)

1. Auto versioning

2. GitOps

Principles
 

#1 The entire system is described declaratively

#2 The canonical desired system state versioned in git

#3 Approved changes that can be automatically applied to the system

#4 Software agents ensure correctness and alert on divergence

# Key concepts
# GitOps Workflow
Push
Push

2/ Kubernetes App repository (verity-k8s-ops)

K8s Templates Repo

CI / CD

GitOps Repo

Push
Publish

1/ App repository (verity-api)

image:vX.Y.Z

Application Repo

CI / CD

Container Registry

Sync
Source of truth

Deploy Operator

K8s Cluster
image:vX.Y.Z
# K8s CI/CD Workflow

Canonical Desired States

verity-api--production
verity-api--staging
myapp:staging
myapp:v1.0.0

#1 The entire system is described declaratively

staging.yaml

production.yaml

verity-k8s-ops

Collection of templates

Rendering

# K8s CI/CD Workflow
verity-api--production
verity-api--staging

Canonical Desired States

#2 The canonical desired system state versioned in git

verity-api--production
└── monochart
    └── templates
        └── deployment.yaml
verity-api--staging
└── monochart
    └── templates
        └── deployment.yaml
git://va-verity-eks-stage-gitops
git://va-verity-eks-prod-gitops
# K8s CI/CD Workflow

#4 Software agents ensure correctness

verity-api--production
└── monochart
    └── templates
        └── deployment.yaml
verity-api--staging
└── monochart
    └── templates
        └── deployment.yaml

ArgoCD

Sync

?

Container Platform

Container Platform

K8s Deployment Anatomy

# Container Platform
Service Discovery
EC2
EC2
EC2
EC2
 ECS
 K8s workers
EKS Control Plane (Master)

 ECS World

 K8s World

# Container Platform

 ECS World

 K8s World

 Task
 Task definition
 Service
 ReplicaSet
 Deployment
 Pod

Kubernetes is a lot more than a simple container scheduler, it can be seen as an automation platform to define multiple pieces of configuration or infra using YAML objects (It's a big REST API)

ECS is a fairly simple scheduler that gets the job done. It is much more lightweight in term of capabilities and requires additional work to bridge all the components together (Prometheus monitoring / Service discovery / ...)

# K8s App Anatomy

Monochart

K8s Tooling

Basics

ArgoCD

# Basics

kubectl

kubectx

kubens

k9s

Official client to interact with K8s

Ease the cluster context switching (can be done with kubectl)

Ease the namespace switching (can be done with kubectl)

Interactive terminal interface that helps you navigate cluster resources

argocd

Official ArgoCD Cli that allows you to do what you do in the UI

Developer 101 - Transitioning from ECS to K8s

By Florian Dambrine

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Developer 101 - Transitioning from ECS to K8s

Developer 101 - How to transition from ECS to K8s

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