CI/CD Fundamentals
Fast recall
Quick revision
Core answer
Whether you understand CI and CD as two distinct goals — 'integrate often to catch conflicts early' vs. 'always releasable so deploys are boring' — and the pipeline stages that realize each.
Treating CI/CD as 'a tool we installed' (Jenkins/GitHub Actions) rather than the practices (small commits, automated tests, fast feedback, deployable main) the tool enforces.
Separate the two intents — CI catches integration bugs early via frequent merge+test, CD makes deploys safe and frequent by keeping main always releasable — then name the pipeline stages and the core metrics: build time, test coverage, deploy frequency, change failure rate, MTTR.
Interview-ready guide
Interview answer
CI/CD is the automated pipeline that builds, tests, and deploys every commit so the software is always releasable.
It exists because the manual path from code to production — build it by hand, hand it to QA, deploy by clicking through a runbook — is slow and error-prone, and automating it makes every change reproducible and tested. I separate the two intents: continuous integration is about merging to main often so integration conflicts are caught early, and continuous delivery is about keeping main always deployable so releases are boring.
The pipeline stages are build, test, scan, package, deploy, and promote, and the non-negotiable rule is fast feedback — if the pipeline takes an hour, people stop trusting it, so I keep the PR gate in minutes with parallelism and caching. And I measure it with the DORA metrics, because having a pipeline isn't the same as it actually working.
CI/CD Fundamentals
Direct Answer
CI/CD (continuous integration / continuous delivery) is the automated pipeline that builds, tests, and deploys every commit so that software is always in a releasable state. It exists because the manual path from code to production — build it, hand it to QA, deploy by clicking through docs — is slow, inconsistent, and error-prone; automation makes every change reproducible, tested, and safely deployable, shrinking risk and lead time from days to minutes.
Common Mistakes & Pitfalls
Treating CI/CD as 'a tool we installed' (Jenkins/GitHub Actions) rather than the practices (small commits, automated tests, fast feedback, deployable main) the tool enforces.
Check your understanding
Answer these without looking back at the article.
- What is the difference between continuous delivery and continuous deployment, and which should a team adopt first?
- How do you keep a CI pipeline fast enough that developers trust the feedback?
- What is the role of feature flags in decoupling deploy from release?
- Which DORA metric tells you a CI/CD change actually improved outcomes, and how would you measure it?
- How do you prevent a flaky test from eroding trust in a green pipeline?
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