State of the Art in Microservices

Microservices architecture and docker

Alexander IvanichevNovember 2015

AGENDA

• Evolution of Software Architecture• Docker concepts• Creating docker hosts with docker-machine• Running docker• Running an Application Server in Docker• Image vs. Container• Changing container behaviour• 3 ways to deploy an application• How to link multiple containers• Introduction to microservices

EVOLUTION OF SOFTWARE ARCHITECTURE

Methodology

Process

Patterns

Platform

Waterfall Agile Lean Engineering

Continuous Delivery

Microservice Architecture

Cloud

Scrum

3-Tier Layered

Windows / Linux

Gated

2-Tier Monolithic

Windows

Device Any DeviceBrowserDesktop

MARKET EVOLUTION

Thick, client – server appOn thick client

1995

Well-defined stack:• O/S• Runtime• Middleware

MonolithicPhysicalInfrastructure

2015Thick, app on

any device

Assembled bydevelopers using best available services

Running on any available set of

physical resources

Microservices

WHAT IS A SERVICE?

The service is peace of software which provides functionality to other peace's of software.Service provides functionality to application for example:Service that provides CRUD orders from database , communicated over network.

DBService

Website

Mobile app

Desktop app

APP

WHAT IS MICROSERVICE ?

An architecture of designing a software in a set of independent services loosely coupled via

lightweight communication.

Recommendation Service

(MongoDB)

Rating Service(Neo4j)

Analysis Service (Spark)

Movie Service (MySQL)

User Service(MySQL)

DiscoveryService

• Application that is spilt into small pieces(suite of small services)• Each service built around business capabilities (1 piece = 1 responsibility) and

independently deployable• Each service running in its own process• loosely coupled : Inter-process communication mechanism, e.g. HTTP, Message

Queue• Bare minimum centralized management service• Each service can be in different programming language and use different data

storage technologies

Microservice formal

definition: Loosely coupled

service orientedarchitecture with bounded

contexts

If every service has to be updated at the same time it’s not

loosely coupled

Microservice

formal definitio

n

Loosely coupled service oriented architecture with bounded

contexts

If every service has to be updated at the same time it’s not loosely

coupled

A Microser

vice formal

definition

Loosely coupled service oriented architecture with bounded

contextsIf you have to know too much about surrounding services you don’t have a bounded context. See the Domain Driven Design book by Eric Evans.

WE HAVE SOA , WHY DOING A MICROSERVICES

SOA problems:• How to size a service - traditional resulted in monolithic services• Service failure – takes all application offline• Scale specific part of a service

Why Microservices:• Efficiently scalable applications• Flexible applications• High performance applications

SOA VS MICROSERVICES Microservices are the kind of SOA we have been talking about for the

last decade. Microservices must be independently deployable, whereas SOA services are often implemented in deployment monoliths. Classic SOA is more platform driven, so microservices offer more choices

in all dimensions.

SOA is an architectural pattern in which application components provide services to other components. However, in SOA those

components can belong to the same application. On the other hand, in microservices these components are suites of independently deployable

services.

SOA THE MONOLITHIC

Accounts

Products

Inventory

Promotions

Internet

Shopping website

Orders

Internal Support website

Data AccessService DB

Customer

• No restriction on size• Longer development

times• Inaccessible features• High levels of coupling• Scaling requires

duplication of the whole• Minor change could result

in complete rebuild

MICROSERVICES SYSTEM EXAMPLE

Accounts Service

Products Service

Inventory Service

Promotions Service

Account Orders

BasketOffers

API G

atew

ayInternet

Client

Shoppingwebsite

Orders Service

Internal Support website

WHY MICROSERVICES• Need to respond to change quickly • Need for reliability• Business domain-driven design• Automated test tools• Release and deployment tools• On-demand hosting technology• On-line cloud services• Need to embrace new technology• Asynchronous communication technology• Simpler server side and client side technology

• Shorter development times• Reliable and faster deployment• Enables frequent updates• Decouple the changeable parts• Security• Increased uptime• Fast issue resolution• Highly scalable and better

performance• Better ownership and knowledge• Right technology• Enables distributed teams

MICROSERVICES DESIGN PRINCIPLES

High CohesionSingle thing done well

Single focus

Approach:Keeps splitting service until it only has

one reason to change

AutonomousIndependently changeableIndependently deployable

Approach:Loosely coupled system, versioning strategy,

microservice ownership by team

Business Domain CentricRepresent business function or represent a business domain

Approach:Business domain specific

Subgroup into functions and areas

ResilienceEmbrace Failure

Default or degrade functionality

Approach:Design for known failuresFail fast and recover fast

ObservableSee system health

Centralized logging and monitoring

Approach:Tools for real-time centralized

monitoring and centralized logging

AutomationTools for testing and feedback

Tools for deployment

Approach:Continuous integration tools Continuous deployment tools

MICROSERVICES COMMUNICATION

Synchronous vs Asynchronous

SYNCHRONOUS COMMUNICATION

Remote procedure call (RPC)• Sensitive to changeHTTP• Work across the internet• Firewall friendlyREST• CRUD using HTTP verbs• Natural decoupling• Open communication protocol• REST with HATEOS

Service One Service Two

http://Service/Account/23

HTTP Verbs:

POST PUTGET

DELETEJSON/XML

1. Make call2. Wait…3. Response

received

Synchronous issues• Both parties have to be available• Performance subject to network quality• Clients must know location of service (host\

port)

ASYNCHRONOUS COMMUNICATION

Event based• Mitigates the need of client and service

availability• Decouples client and serviceMessage queueing protocol• Message Brokers• Subscriber and publisher are decoupled• Microsoft message queuing (MSMQ)• RabbitMQ• ATOM (HTTP to propagate events)Asynchronous challenge• Complicated• Reliance on message broker• Visibility of the transaction• Managing the messaging queueReal world systems• Would use both synchronous and

asynchronous

Accounts Service

Products Service

Inventory Service

PromotionsService

APIGatewa

y

Internet

Client

Shopping website

Orders ServiceInternal

Support website

Message Broker

API GATEWAY

• Request routing • Bundling multiple calls (Composition)• Protocol translation• Authentication • Caching • Versioning• Monitoring• Load balancing

API Gateway is a server that is the single entry point into the system. The API Gateway encapsulates the internal system

architecture and provides an API that is tailored to each client.

.NET STACK TOOLS FOR MICROSERVICES

CI/ CDTeamCityDocker

TestingxUnit.net

NUnitMoq

FsCheck

Communication

RESTProtocol Buffers

RabbitMQParticular

MassTransit

PersistenceMongoDBRavenDBMySQL

CassandraRedis*

Memcached*

Logging and monitoringSerilog

SeqStatsD

GraphiteGrafana

Cabot - monitor and alert

Technology freedom, use the best tools available.

Demo

Docker

WHAT IS DOCKER? 

“ DOCKER IS AN OPEN PLATFORM FOR BUILDING, SHIPPING AND RUNNING DISTRIBUTED APPLICATIONS.

docker.io

Docker engine Docker Hub

APPLICATION DEPLOYMENT HISTORY

 MY APP

+A REAL SERVER

=But wait just a moment !Shouldn't it be all about applications?

Best practice is:Server application

1 : 1

WHAT IF WE WANT RUN MULTIPLE APPS?

[1] [2] [3] [4]

…………...…….…..

[10]

[+] [+] [+] [+]

100%

50%15%

10GB disk space4GB RAM5% CPU

100GB disk space40GB RAM50% CPU

x 10 =

DOCKER VS VMApp A

Bins/Libs

Guest OS

App ABins/Libs

Guest OS

HypervisorHost OS

Server Infrastructure

Virtual Machine• REUSABLE IMAGES

• SNAPSHOTS• SIMPLIFY CLUSTERS

CREATION

Problems?

YES!!"TOO HEAVY"

App ABins/Libs

App ABins/Libs

Docker EngineHost OS

Server Infrastructure

Docker

WHAT IS A CONTAINER?

Host OSServer Infrastructure

Physical Machine

APP

User Space

APP

User Space

APP

User Space

/

dev var proc

sda sda1 lib

/

dev etc lib

sda sda1 systemd

proc

udev

/

dev etc lib

sda sda1 systemd

proc

udev

Container 1(mnt namespace

1)

Container 2(mnt

namespace2)

Docker Engine

Containers

Container ~ VM but lightweight

HOW CONTAINERS WORK?

Physical or Virtual Server

Docker Engine

libcontainer LXC

Host OSNamespace

s cgroups Capabilities

Linux Kernel

LXC = "LINUX CONTAINERS"OS-LEVEL VIRTUALIZATION FOR RUNNING MULTIPLE ISOLATED LINUX SYSTEMSCGROUPS = "CONTROL GROUPS"LINUX KERNEL FEATURE THAT LIMITS AND ISOLATES THE RESOURCE USAGE (CPU, DISK I/O, NETWORK, ETC.)

AUFS= "ADV. MULTI LAYERED UNIFICATION FS"FILESYSTEM WHICH IS BASED ON IMAGES WHERE EVERY MODIFICATION IS A DIFF FROM THE PREVIOUS ONE (LIKE COMMITS IN GIT)

HOW TO INSTALL ?

Linux:$ wget -qO- https://get.docker.com/ | sh

Mac OSX: https://github.com/docker/toolbox/releases/download/v1.9.1c/DockerToolbox-1.9.1c.pkgWindows: https://github.com/docker/toolbox/releases/download/v1.9.1c/DockerToolbox-1.9.1c.exe

http://docs.docker.com/engine/installation/

To use docker it's necessary a linux machine.But.. for Windows and Mac OS X there are some tools to run docker in these OS with a Virtual Machine”.

DOCKER HUB“The Docker Hub is a cloud-based registry service

for building and shipping application or service containers” 

5.6MPulls per Day

240KRepositories

onDocker Hub

65Pulls per Second

https://hub.docker.com/

DOCKER ARCHITECTURE

Docker clientdocker searchdocker run docker start docker pull

Local / Remote Docker daemon

Container 1

Container 2

Host OS

…

DOCKER CLIENT• binds to daemon via unix socket• can access if user is in docker

groupcan• bind to TCP or other UNIX socketDOCKER DAEMON• runs as root user• creates UNIX socket for client

Demo time! #1Docker hello world

Docker

Client

docker run hello-world

Docker Host

docker run <image x>

Image 1 Image 2 Image 3 

Docker Hub

Container 1

Container 2

Image 1 Image 2 Image 3 

DOCKER DEMO OVERVIEW

Daemon

DOCKER BASICS

To show all docker commands just run docker binarydocker

Get command helpdocker pull --help

Usage: docker pull [OPTIONS] NAME[:TAG|@DIGEST]

Pull an image or a repository from a registry -a, --all-tags=false Download all tagged images in the repository --disable-content-trust=true Skip image verification --help=false Print usage

DOCKER BASICSTo show installed docker version

docker -v

Download a docker Ubuntu imagedocker pull ubuntu

Interact with a containerdocker run -it ubuntu bash

Show containersdocker ps

Show container run historydocker ps -a

HOW DOES IT WORK?

Image RegistryContainer

Build DistributeDeploy

DOCKER IMAGESDocker images are the basis of containers.Previously we’ve used Docker images that already exist, for example the ubuntu image.

• Immutable templates • Used to create containers• Used to create other images• Images built in layers• Uses union filesystems to glue layers together• Layer are cached when build• Can be uploaded to registry

docker images # To view all images available docker run --rm -ti somecontainer bash

Basic images commands:

• Built from instructions in Dockerfile• Built FROM base image• Each instruction in Dockerfile creates new layer

DOCKER LAYERS

• AUFS - AnotherUnionFS/advanced multi layered unification filesystem

• Each layer has its own hash • Layer can be tagged• Layers are shared

docker images --tree

2 WAYS TO CREATE DOCKER IMAGES

1.COMMIT WAYdocker commit -m "<menssage>" <image name>docker history <image name>

2.DOCKERFILE WAYdocker build -t <tag> <dockerfile path>

DOCKERFILE REFERENCEFROMMAINTAINERWORKDIRENVRUNCOPYADDEXPOSEVOLUMEUSERCMD

Dockerfile example:

And then we can build itdocker build -t somecontainer somecontainer/

FROM ubuntu RUN apt-get update && apt-get install -y \ python \ telnet ENTRYPOINT ["/bin/bash"]

IMAGES COMMANDS// Build new image based on Dockerfile > docker build -t neueda/myimage:tag ./path/to/Dockerfile

// List containers (-a to print also intermediate layers)> docker images

// Create container based on ubuntu image, create pseudo-TTY, run command in interactive mode > docker run -t -i ubuntu:14.04 rm -rf /etc

// Create new image based on mutations made by container > docker commit -m "Removed /etc directory" -a "Nikolajs Arhipovs" $CONTAINER neueda/ubuntu

// Add tag to untagged image > docker tag 5db5f8471261 neueda/ubuntu:broken

// Push to repository (Docker Hub) > docker push neueda/ubuntu:broken

// Remove image with all intermediate layers on host > docker rmi neueda/ubuntu:broken

Example commands

Demo time! #2Building custom docker image

DOCKER CONTAINER

• Built on top of image• Adds RW layer using union fs

Launch

(build-time) (runtime)

Image Container

511136ea3c5a (rootfs)

6170bb7b0ad1

9cd978db300e

87026dcb0044

core

os/

apac

he

Metadata

Image layering3) 87026dcb00442) 9cd978db300e1) 6170bb7b0ad10) 511136ea3c5a

etc…..

Docker ImageOne per container

Can be shared by many containers

Thin writable layer

CONTAINERS COMMANDSExample commands

// List containers (-a to print also stopped containers)> docker ps

// Show stdout of a container (works as `cat`) > docker logs $CONTAINER_ID

// Attaches to currently running container (like `tail -f`), same as `docker logs -f` > docker attach $CONTAINER_ID

// Stop running containers > docker stop $CONTAINER_ID1 $CONTAINER_ID2

// Start stopped containers > docker start $CONTAINER_ID

// Show running processes > docker top $CONTAINER_ID

// Show all docker-related meta info like net interfaces, port forwarding, volumes > docker inspect $CONTAINER_ID

DOCKER REGISTRY

• Images can be pushed to registry

• Images can pulled from it• Images can be built on FROM

other images pulled from repository

~ $ docker push -h Usage: docker push NAME[:TAG] Push an image or a repository to the registry --disable-content-trust=true Skip image signing

~ $ docker push alexiv/hello The push refers to a repository [alexiv/hello] (len: 1) b88f9422f14d: Image push failed Please login prior to push: Username: alexiv Password: Email: alexiv@gmail.com WARNING: login credentials saved in /Users/alex/.dockercfg. Login Succeeded The push refers to a repository [alexiv/hello] (len: 1) b88f9422f14d: Image already exists 91e54dfb1179: Image successfully pushed d74508fb6632: Image successfully pushed c22013c84729: Image successfully pushed d3a1f33e8a5a: Image successfully pushed Digest: sha256:d659f9011eab6d04b3d9fd9f6324e23505bd1299c52d295c4b04ebe3e58878ce ~ $

Publish image to registry:

Demo time! #3Publishing custom

image to HUB

DOCKER VOLUME A data volume is a specially-

designated directory within one or more containers that bypasses the 

Union File System.~ $ ls /Users/baptou/myDirectory file1 file2 file3 ~ $ docker run -it -v /Users/baptou/myDirectory:/opt ubuntu:latest /bin/bash root@29088b02f260:/# ls /opt file1 file2 file3 root@29088b02f260:/# rm /opt/file2 root@29088b02f260:/# ls /opt file1 file3 root@29088b02f260:/# exit exit ~ $ ls /Users/baptou/myDirectory file1 file3 ~ $

DOCKER KITEMATICRun containers through a simple, yet powerful

graphical user interface.

DOCKER FOR WINDOWS / .NET STACK

• Visual Studio 2015 Tools for Docker• Docker Toolbox• Windows server 2016

DOCKER NEXT STEPS

Tutum Build, deploy, and

manage your apps across any

cloud

Docker Universal Control

On-premises management solution for Docker apps - regardless of where they

run

Docker SwarmDocker Swarm is native clustering

for Docker.

KubernetesManage a cluster

of Linux containers as a single system

THANK YOU!