Splunk and Cribl are not the same competitor and the claim is not the same claim twice. Splunk is the destination and Cairn OBS replaces it, which is what phases 0-7 were for. Cribl is the road: routing, reduction, enrichment, redaction and replay on the way to wherever data is going. Cairn OBS is already a road in shape -- agent, Redpanda, ingest -- and exposes none of a pipeline's controls. The agent cannot filter, drop, sample, mask or re-route anything; ingest normalises a schema and writes it; there is exactly one destination and it is us. Reconciling the two turns up something a cost-led project has to face rather than paper over: most people buy Cribl because Splunk is expensive per gigabyte, so being genuinely cheap per gigabyte removes the main reason to buy Cribl in front of us. That makes the strongest pitch "one system where there were two" rather than "we are also a pipeline vendor" -- but that pitch only survives a buyer if we also do the four things people buy a pipeline for that are not about spend: routing to several destinations, redacting before data leaves the network, archive and replay, and not being locked to one analytics vendor. Those are about control, which is better ground anyway: cost advantages get matched and architectural ones do not. The consequence is uncomfortable and is written down as a decision rather than left to be discovered: competing with Cribl means being able to send data to S3, Splunk HEC, Elastic, OTLP and Kafka -- building features whose purpose is to help data leave this platform. A project that refuses lock-in in its licence and then builds it into its egress would be lying about itself. Four phases follow, ordered so each pays for itself: processing (8), routing (9), archive and replay (10), fleet (11). Processing without routing still shrinks what is stored; routing without processing forwards everything and helps nobody. One design decision is called out now because it collides with a non-negotiable constraint. Cribl's rule language is JavaScript, and embedding a JS engine in a statically-linked musl agent would end "no glibc runtime deps" as a claim. The recommendation is a declarative rule DSL -- matchers and typed actions, no arbitrary code -- deliberately less expressive, small enough to audit and safe to push to ten thousand hosts. The retention/TTL question in architecture.md is no longer deferrable and now says so: Phase 10 asks it from the other side.
4.9 KiB
Project: Cairn OBS — Distributed Log Aggregation & Observability Platform
Mission
Build an open-core, Kubernetes-native centralized logging platform that rivals
Splunk on features but wins on cost-per-GB, modern language stack, and honest
multi-tenant RBAC. 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.mdfor 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:cairnobsctlhas been built out phase by phase since Phase 3. The Terraform provider (/terraform) only exists as of this note -- four resources (cairnobs_dashboardandcairnobs_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_ruleandcairnobs_notification_target, both create/destroy only --alertinghas noPUT /rules/{id}orPUT /targets/{id}to update against), each paired with a read-only data source, built on HashiCorp'sterraform-plugin-framework, reusing the exact same REST contractscairnobsctl dashboards apply/web's dashboard export andcairnobsctl alerts applyalready use. Tenant/RBAC resources are real, disclosed future work -- see/terraform/README.mdfor 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 warningsmust 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.