We have about 50 product teams and every one of them has rolled their own pipeline. Design a CI/CD platform that all 50 can use. Take me through it.
What they are really testing: They want to see if you design for other engineers as your users, not just for one repo. The subtext is whether you can standardise without becoming the team that blocks everyone.
A real interview question
We have about 50 product teams and every one of them has rolled their own pipeline. Design a CI/CD platform that all 50 can use. Take me through it.
What most people say
drag me
“I would set up Jenkins, or maybe GitHub Actions, with a shared library, and then all the teams use it. I would add stages for build, test, and deploy, and use Docker for consistency.”
It names a tool and a stage list but never mentions build volume, queue times, migration, or what happens to the team whose service does not fit the template. That reads like a single-repo pipeline scaled up by hope.
The follow-ups they ask next
How do you stop the platform team becoming the bottleneck for every change?
Talk about templates as versioned products, self-service overrides, and a contribution model where teams can raise PRs against the templates.
How would you roll out a breaking change to the shared template?
Semantic versioning, pinned refs, a deprecation window with a date, dashboards showing who is still on the old version, and a bulk PR bot.
One team's build takes 45 minutes and they blame the platform. What do you do?
Measure first, split queue wait from execution time, and be honest that a slow test suite is a team problem the platform can only help with, not fix.
What the interviewer is listening for
- Asks for build volume and queue time before naming any tool
- Treats the 50 teams as customers and designs a paved road with an escape hatch
- Has a migration plan that starts with pilots instead of a mandate
- Names the flexibility given up and the metric that would change their mind
What sinks the answer
- Jumps straight to a tool name with no numbers
- Assumes all 50 teams will simply comply because leadership said so
- No story for the team whose workload does not fit the template
- Talks about stages and Docker but never about queue time or cost
If you genuinely do not know
Say this instead of freezing. Reasoning out loud from what you do know beats silence every single time, and a good interviewer is listening for exactly that.
“I have not run CI for 50 teams, but here is how I would reason about it: I would first ask how many builds a day and how long they queue, then design one golden path with an escape hatch, and I would expect runner capacity to be the first thing to break.”
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