DevOps is a culture and set of practices bridging development and operations — breaking down the traditional silo where developers write code and a separate team deploys/runs it, in favor of shared ownership across the whole lifecycle. It enhances delivery through automation (CI/CD), faster feedback loops, and treating operational concerns (monitoring, reliability) as part of engineering from day one, not an afterthought handed off later.

CI/CD is the concrete automation backbone DevOps culture is built around — CI catches integration problems early by building/testing every change automatically; CD extends that to automatically (or semi-automatically, with an approval gate) deploy validated changes, shrinking the gap between writing code and it actually running in production.

• Faster, more frequent releases with lower risk per release (smaller, more incremental changes)
• Faster detection and recovery from failures, through better monitoring and shared on-call ownership
• Reduced friction between teams that used to have conflicting incentives (ship fast vs. keep it stable)
• More reliable, repeatable deployments through automation instead of manual, error-prone runbooks

IaC defines infrastructure (servers, networks, databases) in version-controlled configuration files (Terraform, CloudFormation, Bicep) rather than manual console clicks — covered with concrete tool examples in the AWS and Azure interview posts on this blog. The DevOps-level significance is that it makes infrastructure changes reviewable, repeatable, and rollback-able exactly like application code changes.

Shift Left means moving a concern (testing, security review, performance checks) earlier in the development lifecycle — running tests on every commit instead of at the end of a sprint, scanning for vulnerabilities at PR time instead of before a release — because catching a problem earlier is almost always cheaper to fix than catching it later.

Version control (covered exhaustively in the 100 Git interview questions post) is the foundation everything else in DevOps builds on — CI/CD triggers off commits/PRs, Infrastructure as Code is itself just version-controlled configuration, and GitOps (covered later) uses Git as the literal source of truth for what should be deployed.

Automation removes manual, repetitive, error-prone steps from the software delivery process — building, testing, provisioning infrastructure, deploying, and even routine incident remediation. It's not just about speed; a manual process performed slightly differently each time is a real source of production incidents that automation eliminates by construction.

These four DORA metrics (from Google's DevOps Research and Assessment team) are the industry-standard way to measure DevOps maturity — worth naming explicitly in an interview, since they shift the conversation from vague "are we agile" impressions to concrete, measurable outcomes.