Files
cairnobs/PROJECT-SPEC.md
jcoffey-dev 0ee2e9183b Take multi-tenancy off the roadmap
Cairn OBS is self-hosted, and the way to separate two environments is to
run two installations rather than two tenants inside one. Tenancy is the
wrong boundary for that, on three counts this repository demonstrates
rather than assumes: chwriter.WriteBatch is all-or-nothing across
tenants, so one tenant's failure stalls offset progress for every other;
CLICKHOUSE_DEFAULT_ACCESS_MANAGEMENT puts every tenant's data behind a
single superuser credential, as docker-compose.yml's own comment says;
and one binary with one set of migrations moves every tenant together,
which is the opposite of what separate environments are for. A whole
installation idles at about 1.3 GB, so the sharing buys nothing.

The project led with multi-tenant RBAC in the README banner and in
PROJECT-SPEC's goal statement. Both now say what it is instead:
self-hosted. "Open-core" goes with them -- it was already inaccurate,
since CONTRIBUTING states there is no feature gate and no paid tier, and
with enterprise/ off the roadmap there will not be one.

A second identity provider comes off the list of things standing between
this and production-ready. SSO belongs to enterprise/, and a self-hosted
deployment is not waiting on it. Terraform's tenant/RBAC resources move
from "disclosed future work" to not planned.

Nothing is scrubbed from the record. Phase 4 stays shipped, its runbook
stays, and its known gaps stay stated -- rewriting that history would
contradict the candour the Status section is built on. enterprise/ stays
in the tree, AGPLv3 and working, as the answer to a question this
project is not asking.

Signed-off-by: John Coffey <[email protected]>
2026-09-04 18:31:23 -07:00

4.9 KiB

Project: Cairn OBS — Distributed Log Aggregation & Observability Platform

Mission

Build a self-hosted, Kubernetes-native centralized logging platform that rivals Splunk on features but wins on cost-per-GB and a modern language stack. Full architecture spec is in /docs/architecture.md — read it before touching any component. Do not deviate from the storage/query split described there without flagging it to me first.

Cairn OBS is positioned against Cribl as well, which is a different claim rather than the same one twice: Splunk is the destination and Cairn OBS replaces it; Cribl is the road, and Cairn OBS is currently a road that exposes none of a pipeline's controls. Reconciling the two — including the part where cheap storage removes the usual reason to buy Cribl at all, and the part where competing with it means helping data leave this platform — is /docs/positioning.md, along with the four phases of processing, routing, archive/replay and fleet work it implies. Read it before proposing anything pipeline-shaped.

Non-negotiable constraints

  • Distro-agnostic Linux agent: must run identically on RHEL/Debian/Arch/SUSE derivatives via a statically-linked musl binary. No glibc runtime deps.
  • Windows support via native ETW/Event Log API, not a WSL shim.
  • AGPLv3 for the entire project, no exceptions. The enterprise/ module (SSO/multi-tenancy/compliance) was under a commercial-license stub from Phase 4 through Phase 5; Phase 6 relicensed it to AGPLv3, matching core — see /docs/compliance/license-audit-report.md for the full record and its business-model consequences. enterprise/ stays a separate directory that core never imports from, but that boundary is now architectural only (keeps core buildable/deployable standalone, keeps tenant resolution server-side), not a licensing wall.
  • Schema-on-write with OTel semantic conventions as the default schema, with schema-on-read fallback for unstructured text.
  • Every UI action must correspond to a documented REST/gRPC call. No UI-only logic. CLI (cairnobsctl) and Terraform provider are first-class, not afterthoughts. Status: cairnobsctl has been built out phase by phase since Phase 3. The Terraform provider (/terraform) only exists as of this note -- four resources (cairnobs_dashboard and cairnobs_dashboard_panel, both full CRUD, panels as their own resource rather than a nested block since the API manages them independently of their parent dashboard; cairnobs_alert_rule and cairnobs_notification_target, both create/destroy only -- alerting has no PUT /rules/{id} or PUT /targets/{id} to update against), each paired with a read-only data source, built on HashiCorp's terraform-plugin-framework, reusing the exact same REST contracts cairnobsctl dashboards apply/web's dashboard export and cairnobsctl alerts apply already use. Tenant/RBAC resources are real, disclosed future work -- see /terraform/README.md for the full accounting of what is and isn't built, and the same "written but not run against a live stack" verification caveat as everything else Docker-gated in this repo.

Tech stack (pinned — do not substitute without discussion)

Component Language/Tool
Edge agent Rust, musl target
Transport Redpanda (Kafka API)
Ingest/parse Go
Analytical store ClickHouse
Full-text index Tantivy (Rust)
Control plane/API Go, gRPC + REST gateway
Frontend SvelteKit + TypeScript
Deployment Kubernetes Operator (Go, kubebuilder), Helm, docker-compose for local/homelab

Repo conventions

  • Monorepo, one top-level dir per component (see structure below).
  • Rust: workspace-based, cargo clippy --all-targets -- -D warnings must pass.
  • Go: standard go vet + golangci-lint, no globals for shared state.
  • Every component ships with: unit tests, a README.md, and a Dockerfile using distroless or scratch base images where feasible.
  • Conventional commits. Every PR-sized change should be a logically complete, independently revertible unit.
  • Prefer boring, well-understood dependencies over novel ones. This is infrastructure software; operators need to trust it.

Project status

Phase-by-phase scope, what "done" meant for each, and the verification record — including what is not yet shipped and what remains unverified — live in /docs/status.md. Read it before assuming a capability works end-to-end; several are built but unconfirmed against a live stack, and the per-phase runbooks in /docs record exactly how each was checked.

When in doubt

Ask before: changing the pinned stack, adding a new external dependency that pulls in a large transitive tree, or making an architectural decision that isn't already specified in /docs/architecture.md.