Difference between revisions of "DevOps"

Revision as of 00:05, 30 August 2018

DevOps (a clipped compound of "software DEVelopment" and "information technology OPerationS") is a term used to refer to a set of practices that emphasize the collaboration and communication of both software developers and information technology (IT) professionals while automating the process of software delivery and infrastructure changes. It aims at establishing a culture and environment, where building, testing, and releasing software can happen rapidly, frequently, and more reliably.

DevOps is a software development methodology that flattens and streamlines the communication, collaboration, and integration activities between the software developers and information technology (IT) professionals during the different phases of Software Development Life Cycle.

The adoption of DevOps is being driven by the following factors:

• Difficulties in use of Agile and other software development processes and methodologies;
• Demand for an increased rate of production releases from application and business stakeholders;
• Wide availability of virtualized and Cloud infrastructure from internal ("Private Cloud") and external providers (e.g., AWS, GCP, etc.); and
• Increased usage of data centre automation and configuration management tools.

Why DevOps?

• To increase deployment frequency.
• Significantly shorter time-to-market.
• For faster recovery when problems occur.
• For more robust and better integrated security.
• Better product quality, more reliable releases.
• A "shift left" in quality — quality of code, testing, architecture, deployability, and culture.
• For fast feedback loops and effective communication between teams and departments.

Shared Responsibility Model

Serverless

Serverless is a set of architectural principles.^[1]

The principles of serverless^[1]

• Use a compute service to execute code on demand.
• Write single-purpose stateless functions.
• Design push-based, event-driven pipelines.
• Create thicker, more powerful frontends.
• Embrace third-party services.

Serverless pros and cons^[1]

• Pros
  • It is serverless (i.e., no servers to mange)
  • Flexible
  • Scaleable
  • Low cost
  • Less code
• Cons
  • Public Cloud
  • Reliance on Service Level Agreements (SLAs)
  • Non-customizable
  • Vendor lock-in
  • Decentralized challenges

Serverless providers (in the Public Cloud)

• AWS Lambda
• Google Cloud Functions
• Azure Functions
• IBM OpenWhisk

Cost

• Serverless Cost Calculator

CI/CD

Continuous Integration (CI)

• CI is the practice of merging development work with the main branch constantly.
• Developers commit code to a shared repository (e.g., git) on a regular basis.
• The version control system (e.g., GitHub) is monitored and when a commit is detected, a build (e.g., via Jenkins) will be triggered automatically.
• If the build is not "green", developers will be notified immediately.
• Benefits:
  • Detect problems or bugs as early as possible in the development lifecycle.
  • Since the entire code base is integrated, built, and tested constantly, the potential bugs and errors are caught earlier in the life-cycle, which results in better quality software.

Continuous Delivery

• Continual delivery of code to an environment, once the code is ready to ship. This could be staging or production. The idea is that the product is delivered to a user base, which can be QAs or customers for review and inspection.

Continuous Deployment

• The deployment or release of code to production as soon as it is ready.
• Requires both continuous integration and continuous delivery to be operating first.

CI tools include

• Jenkins (a non-hosted solution)
• CircleCI (a hosted solution)
• See Comparison of continuous integration software for a more complete list.

Jenkins

• A continuous integration and build server.
• It is used to manually, periodically, or automatically build software development projects.
• It is an open source CI tool written in Java (requires a minimum of Java 7; Java 8 or newer is recommended).

*aaS

IaaS 

Infrastructure as a Service

PaaS 

Platform as a Service

SaaS 

Software as a Service

FaaS 

Functions as a Service (e.g., AWS Lambda)

Cloud hosted, event driven, stateless, massively scaleable

BaaS 

Backed as a Service

Cloud hosted, managed, undifferentiated, scaleable

Glossary

SOA

Server Oriented Architecture (legacy way of doing things; microservices are the next step in the evolution of moving away from monolithic applications)

References

1. ↑ ^{1.0 1.1 1.2} Sbarski, Peter (May 2017). "Serverless Architectures on AWS". Manning. ISBN 978-1-617-29382-5.

External links

• DevOps Defined — by HashiCorp
• The Twelve-Factor App