DOCKER SWARM

An introduction

Matthias Noback

@matthiasnoback

info@matthiasnoback.nl

some-other-machine

DOCKERA daemon and a client

Docker daemon

client

container container container

SWARMNodes running a Docker daemon "in Swarm mode"

Swarm

Node Node Node

CLI TOOLSdocker-machine and docker

CLUSTER MANAGEMENTEasily add new nodes to a cluster

CONFIGURATIONDocker Compose file (some keys are ignored)

# docker-compose.yml

version: '3'

services: ...

SCALINGConfigure the number of tasks (replicas)

Service (recipe)

Service_Task_1 Service_Task_2

SERVICE DISCOVERY & LOAD BALANCING

Divide incoming requests over available tasks

Service_Task_1:80

(10.0.0.23)

Service_Task_2:80

(10.0.0.24)

service:80

Host 1

MULTI-HOST NETWORKINGSecure, even across data centers

Node Node

Host 2

Node Node

Swarm

NODESNo login required

Use docker-machine to provision them

Use docker to deploy to them

MANAGERS AND WORKERSResilient

Manager

Worker Worker

Manager

Worker

CLOSING NOTES

Considerations

EVERYTHING IS AWESOME

STATEAim for stateless services

STATEFUL SERVICESDon't persist state on the host

Use a "volume scheduler" REX-Ray

STATEFUL SERVICESUse shared state (database)

Maybe use hosted solutions

STATEFUL SERVICESOr: use replication

DISPOSABLE INFRASTRUCTUREMake all setup automated

https://leanpub.com/the-devops-2-1-toolkit

https://leanpub.com/microservices-for-everyone/

https://training.matthiasnoback.nl/