I've set up or fixed well over a hundred CI/CD pipelines at this point. The same five mistakes keep showing up, regardless of whether the team is on GitLab CI, GitHub Actions, or Jenkins.
1. No caching between stages
Rebuilding dependencies from scratch on every job is the fastest way to turn a 3-minute pipeline into a 15-minute one. Cache your package manager's directory, and cache Docker layers if you're building images.
2. Tests and deploys share one monolithic job
If "test" and "deploy" live in the same job, a flaky deploy step blocks you from seeing whether your tests actually passed. Split them — fail fast, deploy separately.
3. No environment parity between staging and production pipelines
Different teams end up hand-editing the staging pipeline and forgetting to port fixes to production. Parameterize one pipeline definition instead of maintaining two.
4. Secrets injected as pipeline variables, unscoped
Broad-scope CI variables mean any branch, including a fork's merge request, can potentially read production credentials. Scope secrets to protected branches and specific environments.
5. No rollback path
Teams build elaborate deploy automation and then have no equivalent "roll back to last known good" job. If deploying is automated, rolling back should be too — ideally a single button.
None of these are exotic problems. They're just easy to miss when you're moving fast, and expensive to leave in place once you're not.
Need your pipeline rebuilt properly the first time? See the GitLab CI/CD Setup package or book a call.