DevOpsContinuous Integration and Delivery

Arthur de Moura Del Esposte - 9534332

Athos Coimbra Ribeiro - 9532618

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Presentation reviewed by Rogério Cardoso

Evolution of Software Engineering

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Evolution of Software Engineering

● Software has evolved in Complexity, Price, Support, Impact…

● Software engineering has evolved as well:

○ Methodologies

○ Practices

○ Tools

● Software Engineering aims to deliver valuable high-quality software.

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Agile software developmentIndividuals and Interactions over Processes and Tools

Working software over Comprehensive documentation

Customer collaboration over Contract negotiation

Responding to change over Following a plan

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● SaaS Book - Chapters 1, 7, 8, 9, 10, 12

● http://www.agilemanifesto.org/

● http://noop.nl/2008/06/top-20-best-agile-development-books-ever.html

Agile software development

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● SaaS Book - Chapters 1, 7, 8, 9, 10, 12

● http://www.agilemanifesto.org/

● http://noop.nl/2008/06/top-20-best-agile-development-books-ever.html

Principles

Practices Methodologies

Eureka! - Automated Tests

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Software Development vs. Tests

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Iterative Development

Continuous Delivery

Refactoring

Test!

Simplicity

Feedback

Collective Code Ownership

Automated Tests● Reproducibility

● Fast and continuous feedback

● Automated coverage analysis

● Reducing uncertainty

● Documentation

● Saves time and money

● Accuracy

Whenever a test fails it proves that something is not working as expected!

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Types of tests

Production Tests like black-box

monitoring may also ensure that small

core functionalities are available.

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The problems with tests

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Common problems about tests

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● Not everybody run tests before commit

● Complex projects tend to have complex tests (Noosfero > 1h)

● Code reviews (MR) depends on whether tests work

● Some tests pass under some environments, but not in others

Running tests

https://xkcd.com/303/

“My tests are running”

Eureka! - Continuous Integration

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Continuous Integration● CI: Executing tests before deploying, which may be challenging for developers

○ Depends on automation

● CI can test different scenarios

○ Browser compatibility

○ Compatibility with different compiler versions

○ External services integration

○ Stress

● Test may run after each single change

SaaS Book, 12.3

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CI

Continuous Integration● Binaries and configuration must be

○ Reproducible

○ Automated

○ We don't want unique snowflakes!

● A new release may be generated each time all tests pass

● Deploy will only succeed if the software was tested and kept stable during

development

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My software is ready, just need to put it into production!

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But wait...

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● How should you handle versioning?

● Should you use a continuous build and deploy model or perform periodic builds?

● How often should you release?

● Do we have access to the production server?

● How should we delivery bug-fixes?

https://www.youtube.com/watch?v=VG5ZOOb5T9o

The gap between Development and Operation

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Traditional Thinking

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● Devs’ job is to add new features and Ops’ job is to keep the site stable and fast

● After finishing the development, send the code to Ops

● “It’s not my machines, it’s your code!” VS. “It’s not my code, it’s your machines!”

● When developers "throw software over the wall" for admins to update servers,

there is a loss of reliability and agility

10+ Deploys Per Day: Dev and Ops Cooperation at Flickr

Eureka! - DevOps

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Dev Ops

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● Developers and Sysadmins should work together in the entire software lifecycle

○ Developers should not build and throw results over the fence

○ Devs think like Ops and Ops think like Devs

● All in the name of Continuous Delivery of valuable software

https://continuousdelivery.com/

Continuous delivery● To run a reliable service, you need a reliable release process (not a snowflake)

● Stability drives agility

● Frequent releases = Fewer changes between versions = Easier troubleshooting

● Releasing can be as painless as pressing a button

● Must be thought from the beginning of the development cycle

○ it's cheaper to put these practices early than later

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Developer + Operations = DevOps● The term DevOps emerged in industry around 2008

● DevOps principles:

○ IT involvement in each phase of the system's design and development

○ Heavy reliance on automation

○ Application of engineering practices and tools to operations tasks

● Development teams control and own their own release process

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DevOps is a Culture!

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DevOps - Basic Concepts

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Ok… But how?● Version control

● Automated tests

● Automated builds

● Automated packaging

● Automated deploy

● Infrastructure as code

● "Push on green"

● Black-box monitoring

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Reliability● Different behavior may arise in different environments

● It is important to work with different environments

○ Development

○ Testing*

○ Staging

○ Production

* Book does not mention a testing environment

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Deploy vs. Release● Release

○ New features available for the client

● Deploy

○ New code that incrementally builds those new features

● Point Release Software

○ Fedora, Debian, Gitlab, Android

● Rolling Release Software

○ Arch Linux, Facebook, Github

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Related Tools

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Version Control System31

https://subversion.apache.org/https://www.mercurial-scm.org/

https://git-scm.com/

Automated tests32

junit.org/

rspec.info/

https://cucumber.io/

Continuous Integration33

https://travis-ci.org/

https://about.gitlab.com/gitlab-ci/

https://jenkins.io/

Continuous Delivery34

https://www.chef.io/

https://puppet.com/

https://www.ansible.com/

Monitoring35

munin-monitoring.org/

www.zabbix.com/

https://www.nagios.org/

Virtualization36

https://www.vagrantup.com/

www.linux-kvm.org/

https://www.docker.com/ https://linuxcontainers.org/

https://www.virtualbox.org/

Our Experiences

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"Toda vez que alguém modifica algo diretamente em um servidor de produção, um gatinho morre em algum lugar".

Antônio Terceiro

Learn more● Site Reliability Engineering: How Google Runs Production Systems

○ Chris Jones

● Engineering Software as a Service: An Agile Approach Using Cloud Computing

○ Fox, Armando and Patterson, David

● Continuous Delivery: Reliable Software Releases through Build, Test, and

Deployment Automation

○ Jez Humble

● Also, see the mentioned tools documentation

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We code!

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