large-scale software developmenttdde06/lectures/tdde06-lecture2-2018.pdf · 1. single developer,...

Large-Scale Software DevelopmentTools and Methods

Scenarios - actions1. Single developer, multiple changes — Version control system 2. Many developers, multiple changes — Distributed version control system 3. Many groups of developers, multiple changes — Package management

system 4. Building artefacts based on multiple files with dependencies — build scripts 5. Conducting multiple actions with inter-dependencies on multiple files … —

Flexible build system 6. Automatically sensing changes and conducting such actions based on

changes — Continuous integration tools

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Scenarios - configuration• Configuration files • Setup scripts • Container environments • Virtual Machines

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Version control — Git

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5

Version control - GIT

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Sample Disorganized Project• “Hey, Anders, could you send me a copy of those changes you

made last Tuesday?” • “Ola, this function doesn’t work anymore. Did you change

something?” • “Sorry, I can’t seem to find those old classes. I guess you’ll just

have to re-implement them.” • “OK, we’ve all been working hard for the last week. Now let’s

integrate everyone’s work together.”

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What is version control?Basic functionality:

keep track of changes made to files (allows roll-backs) merge the contributions of multiple developers

Benefits: facilitates backups increased productivity (vs manual version control) encourages experimentation helps to identify/fix conflicts makes source readily available – less duplicated effort

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Additional benefitsAccountability

who wrote the code? do we have the rights to it?

Support software engineering hooks for peer reviews

Software branches different versions of software need to be maintained, ensure bug fixes shared

Record Keeping Commit logs may tie to issue tracking system or be used to enforce guidelines

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More BenefitsSupport Distribution of Work

Remote work, outsourcing, open-source projects Use in conjunction with “good communication habits” – via email etc.

Rapid Development (XP/Agile) Supports frequent refactoring Helps automate frequent system builds

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The Big Picture

http://blog.mikepearce.net/2010/05/18/the-difference-between-git-pull-git-fetch-and-git-clone-and-git-rebase/

Branching

• Gitseescommitthisway…• Branchannotateswhichcommitweareworkingon

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Branching

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Merging

• Whatdowedowiththismess?– Mergethem

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Merging

• Stepstomergetwobranch– Checkoutthebranchyouwanttomergeonto– Mergethebranchyouwanttomerge

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Package management systems

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Dependency management

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Dependency management issues• Is a request to modify the current software component graph

satisfiable? – Are additions compatible with other components? – Are deletions safe with respect to other dependencies?

• Given a component, determine versions of other components we can safely rely on

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Dependency management as satisfiability

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(a | b | c) & (d | e | f) ... = TRUE

(a | b | c) & (-c) & (-b | -a) ... = TRUE

A requires B provided by B1, B2, B3Rule: (-A | B1 | B2 | B3)

A conflicts with B provided by B1, B2, B33 Rules: (-A | -B1), (-A | -B2), (-A | -B3)

Rules

Dependency management issues• Y depends on X >= 1.8. X makes binary incompatible changes from

v. 1.9 to v. 2.0... • Can components be installed from local sources as well as from

remote? • Should OS-specific dependency management or language-specific

be used?

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Software package management systems

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Name Environment Format

NuGet .Net CLR XML

Gradle JVM XML

dpkg/APT Linux Ar archive

Rubygems Ruby Ruby

MSI Windows In-file DB

BSD Ports OS X/Linux/BSD Makefile

...

Maven

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mvn -h

Lifecycles

Clean

Default

Site

validatecompiletestpackageverifyinstalldeploy

Maven example 38

Olas-MacBook-Pro:java-petclinic olale$ mvn graphwalker:test[INFO] Scanning for projects...[ … ][INFO] >>> graphwalker-maven-plugin:3.4.2:test (default-cli) > [graphwalker]test-compile @ java-petclinic >>>[INFO][INFO] --- graphwalker-maven-plugin:3.4.2:generate-sources (generate-sources) @ java-petclinic ---[INFO][INFO] --- graphwalker-maven-plugin:3.4.2:validate-models (default-cli) @ java-petclinic ---[INFO][INFO] --- graphwalker-maven-plugin:3.4.2:generate-sources (default-cli) @ java-petclinic ---[INFO][INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ java-petclinic ---[INFO] Using 'UTF-8' encoding to copy filtered resources.[INFO] Copying 10 resources[INFO][INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ java-petclinic ---[INFO] Nothing to compile - all classes are up to date[INFO][INFO] --- graphwalker-maven-plugin:3.4.2:validate-test-models (default-cli) @ java-petclinic ---

Maven — structure

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mvn archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

Maven — Configuration

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<parent> <groupId>org.graphwalker.example</groupId> <artifactId>graphwalker-example</artifactId> <version>3.4.2</version> </parent>

<artifactId>java-petclinic</artifactId>

<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.1</version> <configuration> <source>1.7</source> <target>1.7</target> </configuration> </plugin> <plugin> <groupId>org.graphwalker</groupId> <artifactId>graphwalker-maven-plugin</artifactId> <version>${project.version}</version>  <executions> <execution> <id>generate-sources</id> <phase>generate-sources</phase> <goals> <goal>generate-sources</goal> </goals> </execution> </executions> </plugin> </plugins> </build>

Automation and languages for … development41

ASM

C

Java

Compiler

JVM

OS

Buildtools

Testautomation,packaging,…CIworkautomationMultipledevelopers/languages/components





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Jenkins

43

Jenkins 44

Workflowautomationtool

Jenkins 45

Workflowautomationtool-pipelines

node{//<1>stage('Build'){//<2>sh'make'//<3>}

stage('Test'){sh'makecheck'junit'reports/**/*.xml'//<4>}

stage('Deploy'){sh'makepublish'}}

Groovy(JVM-basedlanguage)

Travis CI 46

Automation and languages for … deployment

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Singlefile,structurednon-programminglanguage.Requirementsinstalled,updated,startedmanually.Deploymentthroughmanualscripts

Programminglanguage Automationofsetup

Chef/Puppet/Ansible/Salt/Terraform

Isolationofcomponents

Xen/SolarisZones,Docker/Chroot

Chef/Puppet/Ansible/Salt/Terraform/…• Automates setup of environments for development/deployment • Introduces programming languages for your infrastructures

• Declarative (Terraform/Puppet) - What is the desired end-state? • Imperative (Chef/Ansible) - How do you achieve it?

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Deployment

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Market View: Evolution of IT1995 2015

Runningonanyavailablesetof

physicalresources(public/private/virtualized)

Assembledbydevelopersusingbestavailable

services

Thinapponmobile,tabletThick,client-serverapp

onthickclient

Well-definedstack:-O/S-Runtime-Middleware

MonolithicPhysical

Infrastructure

Challenges2015

Howtoensureservicesinteractconsistently,avoid

dependencyhell

Howtomigrate&scalequickly,ensurecompatibility

HowtoavoidnXndifferentconfigs

Runningonanyavailablesetof

physicalresources(public/private/virtualized)

Assembledbydevelopersusingbestavailable

services

Thinapponmobile,tablet

Static website

Web frontend

User DB

Queue Analytics DB

Background workers

API endpoint

nginx 1.5 + modsecurity + openssl + bootstrap 2

postgresql + pgv8 + v8

hadoop + hive + thrift + OpenJDK

Ruby + Rails + sass + Unicorn

Redis + redis-sentinel

Python 3.0 + celery + pyredis + libcurl + ffmpeg + libopencv + nodejs + phantomjs

Python 2.7 + Flask + pyredis + celery + psycopg + postgresql-client

Development VM

QA server

Public Cloud

Disaster recovery

Contributor’s laptopProduction Servers

The ChallengeMultip

licity

ofS

tacks

Multip

licity

of

hardware

environm

ents

Production Cluster

Customer Data Center

Doservicesandappsinteract

appropriately?

CanImigrate

smoothlyandquickly?

Results in NxN compatibility nightmareStatic website

Web frontend

Background workers

User DB

Analytics DB

Queue

Development VM QA Server Single Prod

ServerOnsite Cluster

Public Cloud

Contributor’s laptop

Customer Servers

? ? ? ? ? ? ?

? ? ? ? ? ? ?

? ? ? ? ? ? ?

? ? ? ? ? ? ?

? ? ? ? ? ? ?

? ? ? ? ? ? ?

Static website Web frontend User DB Queue Analytics DB

Development VM

QA server Public Cloud Contributor’s laptop

Placing code in movable boxes Multip

licity

ofStacks

Multip

licity

of

hardware

environm

ents

Production Cluster



appropriately?

CanImigrate

smoothlyandquickly

…that can be manipulated using standard operations and run consistently on virtually any hardware platform

An engine that enables any payload to be encapsulated as a lightweight, portable, self-sufficient container…

Static website Web frontend User DB Queue Analytics DB

Development VM

QA server Public Cloud Contributor’s laptop

Or…put more simplyMultip

licity

ofStacks

Multip

licity

of

hardware

environm

ents

Production Cluster



appropriately?

CanImigrate

smoothlyandquickly

Operator: Configure Once, Run Anything

Developer: Build Once, Run Anywhere (Finally)

Static website

Web frontend

Background workers

User DB

Analytics DB

Queue

Development VM QA Server Single Prod

ServerOnsite Cluster

Public Cloud

Contributor’s laptop

Customer Servers

Containers tries solves the NxN problem

Two types of boxes

• Virtualization (Virtual machines)• Xen • KVM• QEMU • Virtual Box • UML • ….

• Containers • Docker (LXC)• LXD• CoreOS (rkt)

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What is Docker?Docker is an open-source project that automates the deployment of applications inside software containers, by providing an additional layer of abstraction and automation of operating system–level virtualization on Linux.

[Source: en.wikipedia.org]

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Docker: Namedocker [naut.]: der Dockarbeiter, der Hafenarbeiter

Source: leo.org

• Provide a uniformed wrapper around a software package: «Build, Ship and Run Any App, Anywhere» [www.docker.com]

– Similar to shipping containers: The container is always the same, regardless of the contents and thus fits on all trucks, cranes, ships, ...

[www.docker.com]

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Docker vs. Virtual Machine

Source: https://www.docker.com/whatisdocker/

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Docker Technology

• libvirt: Platform Virtualization • LXC (LinuX Containers): Multiple isolated

Linux systems (containers) on a single host • Layered File System

[Source: https://docs.docker.com/terms/layer/]

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Run Platforms• Various Linux distributions (Ubuntu, Fedora, RHEL, Centos,

openSUSE, ...) • Cloud (Amazon EC2, Google Compute Engine, Rackspace,

Azure ) • Mac • Windows

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Hello WorldSimple Command - Ad-Hoc Container • docker run ubuntu echo Hello World – docker images [-a]

– docker ps –a

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Terminology - Image• Persisted snapshot that can be run

– images: List all local images – run: Create a container from an image and

execute a command in it – tag: Tag an image – pull: Download image from repository – rmi: Delete a local image

• This will also remove intermediate images if no longer used

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Terminology - Container• Runnable instance of an image

– ps: List all running containers – ps –a: List all containers (incl. stopped) – top: Display processes of a container – start: Start a stopped container – stop: Stop a running container – pause: Pause all processes within a container – rm: Delete a container – commit: Create an image from a container

Container cid4

Container cid3

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Image vs. ContainerBase Image ubuntu:latest

Container cid1

run

Container cid1

cmd à new state

New Image iid1

commit

base image

Container cid2

run

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Dockerfile• Create images automatically using a build script: «Dockerfile» • Can be versioned in a version control system like Git or SVN,

along with all dependencies • Docker Hub can automatically build images based on

dockerfiles on Github

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Dockerfile Example• Dockerfile:

– FROM ubuntu ENV DOCK_MESSAGE Hello My World ADD dir /files CMD ["bash", "someScript"]

• docker build [DockerFileDir]

• docker inspect [imageId]

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FROM ubuntu

MAINTAINER Anders

RUN apt-get install -y python-software-properties python python-setuptools ruby rubygems

RUN add-apt-repository ppa:chris-lea/node.js

RUN echo "deb http://us.archive.ubuntu.com/ubuntu/ precise universe" >> /etc/apt/sources.list

RUN apt-get update

RUN apt-get install -y nodejs

RUN apt-key adv --keyserver keyserver.ubuntu.com --recv 7F0CEB10

RUN echo "deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen" | tee -a /etc/apt/sources.list.d/10gen.list

RUN apt-get -y update

RUN apt-get -y install mongodb-10gen

RUN easy_install supervisor

RUN echo_supervisord_conf > /etc/supervisord.conf

RUN printf "[include]\nfiles = /var/www/Supervisorfile\n" >> /etc/supervisord.conf

ADD . /var/www

RUN cd /var/www ; npm install

CMD ["/usr/local/bin/supervisord", "-n", "-c", "/etc/supervisord.conf"]

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Mount Volumes• docker run –ti –v /hostLog:/log ubuntu

• Run second container: Volume can be shared – docker run –ti --volumes-from firstContainerName ubuntu

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Publish Port• docker run –t –p 8080:80 ubuntu nc –l 80

– Map container port 80 to host port 8080 – Check on host: nc localhost 8080

• Link with other docker container – docker run -ti --link containerName:alias ubuntu

– See link info with set

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Around Docker• Docker Images: Docker Hub • Vagrant (Also for VMs) • Automated Setup

– Puppet, Chef, Ansible, ...

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Docker Hub• Public repository of Docker images

– https://hub.docker.com/ – docker search [term]

• Automated: Has been automatically built from Dockerfile – Source for build is available on GitHub

https://hub.docker.com/

https://hub.docker.com/

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