DevOps Guides

DevOps is a culture and set of practices in which software development (dev) and IT operations (ops) teams work toward shared goals instead of in separate silos. Building, testing and releasing code is automated through CI/CD pipelines, infrastructure is defined as code and the live system is monitored continuously. The aim is to ship changes more often with fewer errors and to spot and fix problems quickly. DevOps is a way of working, not a specific tool or job title.

CI/CD stands for continuous integration and continuous delivery or deployment. In continuous integration, every code change merged into the shared repository is automatically built and tested. In continuous delivery, a version that passes the tests is kept ready to release with a single approval; in continuous deployment, it goes live automatically without waiting for a person. The chain of these steps is called a CI/CD pipeline, and GitHub Actions, GitLab CI and Jenkins are common tools for building one.

Docker is used to package an application, along with the libraries, settings and dependencies it needs, into a portable unit called a container. The same container runs the same way on a developer's laptop, a test server and in production, so code that works on one machine no longer breaks on another. Containers share the host's operating system kernel, which makes them lighter than virtual machines. Docker Compose can run several services, such as an app and its database, together.

Kubernetes is an open source container orchestration platform that automates deploying, scaling and managing many containers across multiple servers. Docker packages and runs an application as a container; Kubernetes decides which server those containers run on and how many copies run, restarts the ones that crash and can add copies when traffic grows. So the two are not rivals but complements. For projects with only a few services, the management overhead Kubernetes brings is often unnecessary.

Cloud computing is renting computing resources such as servers, storage, databases and networking over the internet, usually on a pay-as-you-go basis, instead of buying your own hardware. Amazon Web Services (AWS), Microsoft Azure and Google Cloud are the best-known providers. Services usually come in three models: infrastructure (IaaS), platform (PaaS) and ready-made software (SaaS). Scaling resources up or down in minutes is a major advantage; keeping costs under control and setting access permissions correctly need care.

A DevOps engineer builds, automates and maintains the path software takes from build and testing to release and day-to-day operation. They set up CI/CD pipelines, package applications with Docker, run infrastructure on Kubernetes or cloud services and define that infrastructure as code with tools such as Terraform. They also set up monitoring and alerts, respond to outages and keep backups and security updates on track. Linux, networking basics, a scripting language and cloud platforms are the core skills.