DevOps

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

IaaS (Infrastructure)	PaaS (Container)	SaaS (Abstract)
Data	Data	Data
Application	Application	Application
Operating System	Operating System	Operating System
Virtualization	Virtualization	Virtualization
Infrastructure	Infrastructure	Infrastructure
Physical	Physical	Physical

Serverless

Serverless is a set of architectural principles.

The principles of serverless

• 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

• 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

*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)

External links

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