What is DevOps? It is a way of working that brings software development and IT operations together, so teams can deliver changes quickly and reliably. DevOps combines culture, practices and tools. Its goal is simple: ship value to users faster, with fewer failures and quicker recovery when things go wrong.
Where DevOps came from
Traditionally, developers wrote code and handed it to a separate operations team to deploy and run. Developers wanted change, while operations wanted stability, so releases were slow and painful. From around 2009, practitioners began promoting “DevOps”: shared goals, automation and fast feedback across both groups.
Core principles
A popular summary is CALMS:
- Culture: shared responsibility, trust and blameless learning.
- Automation: automate builds, tests, infrastructure and deployments.
- Lean: small batches, limited work in progress and less waste.
- Measurement: use data to guide decisions.
- Sharing: open knowledge, tools and feedback between teams.
The DevOps lifecycle
DevOps is often drawn as an infinity loop that never ends.
| Stage | What happens | Example tools |
|---|---|---|
| Plan | Define work and priorities | Jira, GitHub Issues |
| Code | Write and review code | Git, GitHub, GitLab |
| Build | Compile and package | Maven, npm, Docker |
| Test | Run automated tests and scans | JUnit, pytest, SonarQube |
| Release | Approve and version artefacts | Container registries, artefact repositories |
| Deploy | Roll out to environments | Jenkins, GitHub Actions, Argo CD |
| Operate | Run and scale services | Kubernetes, Terraform, Ansible |
| Monitor | Observe health and usage | Prometheus, Grafana, OpenTelemetry |
Key practices
Continuous integration and delivery (CI/CD)
Developers merge small changes often, and pipelines build, test and prepare every change for release. With continuous deployment, passing changes go live automatically.
Infrastructure as code
Servers, networks and cloud resources are defined in code with tools like Terraform or Ansible. As a result, environments are repeatable and reviewable.
Containers and orchestration
Containers package applications consistently, and Kubernetes runs them at scale.
Monitoring and observability
Metrics, logs and traces show how systems behave, so teams can detect and fix problems quickly.
Measuring success
The DORA research programme recommends four key metrics:
- Deployment frequency.
- Lead time for changes.
- Change failure rate.
- Time to restore service.
High-performing teams deploy often, with short lead times, few failures and fast recovery.
DevOps and security
Security must be part of the pipeline, not a final gate. DevSecOps adds automated code, dependency, secret and infrastructure scanning, plus runtime monitoring. Read our DevSecOps interview questions for the key concepts.
DevOps and the cloud
Cloud platforms provide on-demand infrastructure, managed services and APIs that DevOps teams automate. In practice, AWS, Azure and Google Cloud are the most common environments.
Careers in DevOps
Common roles include DevOps engineer, site reliability engineer (SRE), platform engineer and cloud engineer. Useful skills:
- Linux and networking fundamentals;
- scripting in Bash and Python;
- Git and CI/CD tools;
- Docker and Kubernetes;
- Terraform or Ansible;
- a major cloud platform;
- monitoring and incident response.
Prepare with our DevOps interview questions.
Sources
Running Linux servers in production? Our Linux server hardening & security audit checks configuration, patching, SSH and logging. You can also use our free Linux server hardening checklist, or contact us.
