Migrating Swarm Applications to KubernetesJanakiram MSVAnalyst | Advisor | ArchitectJanakiram & AssociatesGoogle Developer Expert

Joseph JacksSr. DirectorApprenda Founder, KubeCon

Announcing The Kubernetes Webinar Series

● Monthly webinar focused on helping you get started with Kubernetes● Delivered by the experts from the container ecosystem● Each webinar introduces a concept to accelerate your learning● No specific prerequisites

○ Basic understanding of Docker will help

● All attendees will get $100 Google Cloud Platform Credits● Win free annual and monthly subscriptions of MAPT eBook library● The recording of this webinar will be available at Kubernetes.live

Objectives

● Overview of Swarm-Mode● Exploring the Reference Application Architecture● Mapping Swarm Deployment to Kubernetes● Scaling and Optimizing Application

Overview of Swarm Mode

● Swarm mode brings cluster management and orchestration to Docker Engine

● Bundled with Docker Engine 1.12 or above - Based on Swarmkit● Swarm mode is initialized in one of the nodes, which becomes the

manager● Worker nodes join an existing Swarm controller● Docker CLI is used for managing the cluster including adding and

removing nodes

Key Concepts of Swarm Mode

● Manager Node○ Dispatches the submitted tasks to worker nodes

● Worker Node○ Receive and execute tasks dispatched from manager nodes

● Service○ Definition of tasks to execute on worker nodes

● Task○ Carries a Docker container and the commands to run inside the container

● Load balancing○ Manager node uses ingress load balancing to expose the services

Swarm Mode Architecture

Swarm Mode Architecture

Overview of Sample Deployment

● API Management service based on open source Kong● PostgreSQL is used as the persistent backend● Nginx is acting as the API proxy● Node.js based Dashboard to manage APIs● Each component is packaged as a Docker container

PostgreSQLKongDashboard

DemoDeploying Microservices in Swarm Mode

Quick Recap - Kubernetes Architecture

DeploymentMaster

kube-proxyDocker kubelet

Supervisord

fluentdWeb Pod

Node

DB Pod

Deployment

Web

DB

Mapping Swarm Concepts to Kubernetes

● Manager Node● Worker Node● Service● Task● Replicas● DNS-based Service Discovery● Ingress● PublishedPort● Volumes● Overlay Network

Swarm Mode● Master● Node● Deployment● Pod● Replica Set● DNS-based Service Discovery● Service● Endpoint● Persisted Volumes● Flat Networking space

Kubernetes

Mapping Swarm Concepts to KubernetesSwarm Kubernetes

Controller Manager Master

Slave Worker Nodes

Workload Definition Service Deployment

Deployment Unit Task Pod

Scale-out Definition Replicas Replica Set

Service Discovery DNS DNS

Load Balancing Ingress Service

Port PublishedPort Endpoint

Storage Volumes Persistent Volumes / Claims

Network Overlay Flat Networking Space

DemoMigrating the Application to Kubernetes

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