# Release Engineering & Continuous Delivery
- Treat every commit as a deployable artifact.
- Use CI to run tests and build artifacts; use CD to push to staging/production.
- Pin versions, sign artifacts, and audit changes.
- Release trains > hero deploys: small batches, fast feedback.

# 11 Factor Apps (12 Factor methodology adapted)
1. Codebase: one repo per service, tracked in version control.
2. Dependencies: explicit manifests, lockfiles, isolated environments.
3. Config: env vars/secrets outside code.
4. Backing services: attach databases/queues as resources.
5. Build/run separation: immutable artifacts, separate runtime.
6. Processes: stateless, share nothing, push state out.
7. Port binding: self-contained HTTP service.
8. Concurrency: scale by process model.
9. Disposability: fast startup, graceful shutdown.
10. Dev/prod parity: avoid one-off configs.
11. Logs/logging: treat logs as event streams.

# Microservices Architecture
- bounded context per service
- async communication where possible
- API contracts + versioning
- independent deployability
- observability: metrics, traces, structured logs

# Disk capacity incident

Root filesystem usage at or above 85% is an operations incident.

1. Capture the initial state with `df -h / /var/lib/gitea`.
2. Inspect directory sizes and active processes before cleanup. Reclaim only
   disposable caches and abandoned temporary environments. Responders must not
   delete Gitea data, repositories, databases, secrets, or active release
   artifacts.
3. Re-run `df -h / /var/lib/gitea`; usage must be below 85%.
4. Confirm the release path with `systemctl is-active gitea act_runner`, then run
   the repository test suite.

Record the before and after usage in the incident ticket. If safe cleanup cannot
restore capacity below 85%, keep the incident open and escalate storage
expansion rather than removing durable data.