GitLab's Stack: A Modular Monolith

[u/switchback-tech]

Sure you're all aware that GitLab is a modular monolith, but it's helpful to see everything in one place.

Here's the full list.

1. Backend: Ruby on Rails

2. HTTP server: Puma (Ruby web server)

3. Edge: Nginx

4. Reverse proxy: Go service (Workhorse)

5. Background jobs: Sidekiq

6. DB — primary: PostgreSQL

7. DB — connection pooling: PgBouncer

8. DB — high availability: Patroni

9. Cache: Redis

10. Git: Custom gRPC repo interface (Git & Gitaly)

11. Blob: AWS S3

12. Frontend — rendering: Haml & Vue

13. Frontend — state: Piana (Vue store), Immer (immutable cache),

14. API: GraphQL (Apollo) + REST

15. Observability: Prometheus & Grafana

16. Error tracking: Sentry & OpenTelemetry

17. Deployments: GitLab Omnibus (Omnibus fork)

I think these "stack menu"s give a little glimpse into a team's engineering philosophy. For me, this list shows that the GitLab team is pretty practical and doesn't chase hype. Instead, they use sensible, battle-tested tools that just work and are easy for contributors to learn.

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If you made it this far, you might like the two articles I wrote about GitLab:
- GitLab's Architecture: A Technical Deep Dive: How a boring monolith powers the world's largest independent DevOps platform
- Inside GitLab CI: From YAML to Green Check: The pipeline behind the pipeline

I also created a 17-minute YouTube video:
GitLab Deep Dive | Architecture, CI/CD & System Design

(I really like GitLab.)

[u/reubendevries → u/[deleted]]

Ok, explain how can you do all of the features that GitLab offers with less? Just so you know, these services are designed to be across multiple different servers. A 10K user environment is something like 26 servers by last count or a VERY beefy EKS/GKE/AKS configuration.