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Design a CI/CD pipeline like GitHub actions

PremiumCloud infrastructureMedium

  • CI/CD
  • Ephemeral runners
  • Job queue

Quick answer

This cloud infrastructure interview question asks you to design a CI/CD pipeline like GitHub actions. Aim for a design that runs reliably and securely in the cloud at a sensible cost, then explain the services, regions, deployment and trade-offs. Interviewers want to see how you balance reliability, security and cost.

The problem

Design a CI/CD pipeline service like GitHub Actions: on every push or pull request it runs the workflow file in the repository, schedules its jobs onto isolated runners and deploys the result. The hard parts are running untrusted code safely, absorbing bursty queues and never deploying out of order.

A workflow is a YAML file in the repository. It lists jobs, the jobs each one needs first, the runner type and the steps. A build that passes can be promoted to staging and then production, where a deployment environment can require a human approval.

What must a CI/CD pipeline like GitHub actions do?

  • Triggers: Start a workflow run on push, pull request, a schedule or a manual click, using the workflow file at that commit.
  • Job graph: Run jobs as a DAG: independent jobs in parallel, dependent jobs after their needs succeed, with matrix expansion (3 OS × 4 versions = 12 jobs).
5 more requirementsUnlock to see all

How well must it do it?

  • Isolation: A job must never read another customer's code, secrets or cache; a hosted runner serves one job and is then destroyed.
  • Queue latency: A job waits under 30 s for a hosted Linux runner at p95, even at the weekday morning peak.
3 more requirementsUnlock to see all

What scale should you design for?

Use these numbers in your estimates.

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Key concepts

  • CI/CD
  • Ephemeral runners
  • Job queue
  • Workflow DAG
  • Deployment environments
  • OIDC

How you’ll practise

6 short steps · save and come back any time
  1. Requirements
  2. Environments and topology
  3. Deployment pipeline
  4. Reliability and disaster recovery
  5. Observability and cost
  6. Wrap-up

Lala, personalized to you, gives a hint when you ask and reviews your design when you are ready.

What do interviewers look for?

In any cloud infrastructure design round.

  • Clarifies availability, security and cost targets
  • Chooses managed services with reasons
  • Plans regions, zones and failover
  • Covers identity, secrets and network boundaries
  • Explains deployment, rollback and observability
  • Keeps an eye on cost as usage grows

Questions people ask about this interview question

Which design type is this question?
It is a cloud infrastructure question. You design a CI/CD pipeline like GitHub actions and explain your choices the way you would in an interview.
Is this question asked at entry level?
It is marked Medium. Entry-level engineers can practise it, but it expects you to reason about requirements and trade-offs, not only list components.
What should I cover first?
Start with the workloads, the availability target and the security and cost limits. Agree on scope with the interviewer before you design anything.
Can I practise it for free?
It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.

Related questions

Updated · Written by the SevyDevy team

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