adrian mouat - docker: why, what, and for what? | codemotion milan 2015

ChiefScientist@ContainerSolutions

Writing"UsingDocker"forO'Reilly@adrianmouat

http://www.container-solutions.com

WhatDockerisWhyit'ssopopularWhatthemainusecasesare

BothprovideisolatedenvironmentsLargeoverlapinusecases

NovirtualisationDockerismuchmoreefficient

BootsinunderasecondMuchsmallerimagesize

Developerorientedinterface

ADockercontainerisaportablestoreforasinglecomponentanditsdependencies

LikeastoppedVMBuiltfromDockerfilesListofrepeatablestepsRedisDockerfile

RepositoryforimagesDistros

Centos,Debian,Alpine...Languages

Go,Java,C...Applications

Redis,Wordpress,RevealJS...

ControlGroupsGroupstasksControlsresources

AppliesLimitsIsolatesAccountsfor

ProcessFilesystemNetworkPlussomeothers

LimitwhatacontainercandoRestrictkernelcalls

Basisof"UnionFilesystem"ImagesmadeupofmulitplereadlayersContainersputar/wlayerontopOverlay,AUFS,ZFS,BTRFS,devicemapper...

Jails,chroot,SolarisZones,VirtuozzoBorgLXC

GluedtogethermissingpiecesFastandportableTargetteddevelopers

ContainersbecomeunitofdevelopmentShippedbetweendev,testandprodWorksthesameeverywhereContainsdependenciesandenvironment

VMstooslowandclunkyDeveloperinterfacelacking

DevelopfasterTestfasterDeployfaster

ConsistentenvironmentDeployfasterTestfasterMakesureyoushipwhatyoutest!

SmallservicesthatdoonethingwellLooselycoupledAsopposedtomonolithsScale-outasopposedtoscale-up

CansimplifysoftwareScaleonlyneededservicesEasiertochangeEasiertodistributeUsebesttoolforthejob

Howtodividesystemintomicroservices?FastfunctioncallsbecomeslowRESTcalls

Complexityismovedtonetwork

GoldenimagesDon'tallowrunningcontainerstochangeInsteadreplacewithnewcontainersSimpler,noneedforCM

Auditimages,notrunningcontainersCan'thavemovedfromimage

NotyetconsideredassecureasVMsUsebothAddingisolation

Patterns&BestPracticesSignals,logging,envvars,pods,sidecars,ambassadors...Stillbeingdeveloped

Patterns&BestPracticesSignals,logging,envvars,pods,sidecars,ambassadors...Stillbeingdeveloped

OrchestrationBattlefield!Kubernetes,Mesos,Swarm?

Patterns&BestPracticesSignals,logging,envvars,pods,sidecars,ambassadors...Stillbeingdeveloped

OrchestrationBattlefield!Kubernetes,Mesos,Swarm?

UnikernelsHugepotentialMayovertakecontainers

WhatAportablestoreforasinglecomponentanditsdependencies

WhyAgilityforthewin

WhatForMicroservicesCI/CDImmutableInfrastructure...