DongHyeonkaandClaude Opus 5
b2963105a8
The keycloak project ended with four open questions that design could not
settle. A two-VM lab was built to answer them by measurement, and this is
that material: 26 experiments, 125 raw command outputs, 22 browser captures.
Follows the import procedure in README.md.
source/ the originating repository verbatim — 78 documents, 28 SVGs,
8 manifests, plus .source-revision recording the commit
final/ the SSOT
document.md 729 lines written from the 29 experiment documents, not
concatenated: what was predicted, what was measured, and
where the measurement itself was wrong
evidence/raw 125 outputs, flattened to <experiment>__<file> because
the originals collided (01-baseline.txt appeared three
times) and the audit only globs the top level
evidence/meta one per raw file; command and exitCode are null and the
README says why rather than inventing them
evidence/browser 22 captures
assets/ three diagrams through techviz
.techviz/ their VizSpecs
A separate project rather than an addition to keycloak: the B-layer answers
that project's four questions, but the A, C and D layers are about cluster
failure, SSO and operations, and one document.md should hold one subject.
The four question records there can point here through 관계.
Recorded rather than papered over: only three of the 28 diagrams were
remade. The repository forbids hand-drawn SVG and forbids titles inside the
canvas; all 28 originals carry both, so converting them is redrawing, not
reformatting. They stay in source/ and the gap is written into the document.
verify-pipeline.py passes. audit-records.py reports no issues.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
A-2 — PostgreSQL 정지 증거
2026-09-04 11:56–11:58 KST · Keycloak 26.7.0
해설: docs/experiment-a2-database-loss.md
| 파일 | 무엇을 보여주는가 |
|---|---|
01-baseline.txt |
정지 전 — 양쪽 Ready, cluster_size=2 |
02-setup-sessions.txt |
양쪽 노드에 세션 하나씩. 캐시는 각자 노드에만 |
03-four-paths.txt |
네 경로 전부 500. 캐시를 가진 노드도 실패 — refresh 는 쓰기다 |
04-health-and-service.txt |
전면 장애 증거 — Ready 파드 0개, ready 주소=[], 외부 503, database connections: DOWN. JWKS·.well-known 은 200 |
05-recovery.txt |
up=1 인 채로 503. DB 복귀 15초 후 재시작 0회로 자동 회복, 세션 5건 생존 |
a2-up-stayed-1-during-outage.png |
Grafana — up{job="keycloak"} 이 전면 장애 내내 1에 평평 |
핵심 세 줄
- DB 는 단일 장애점이다. Keycloak 을 몇 대로 늘려도 같이 죽는다 — Ready 파드 0개, 외부 503.
- 캐시는 읽기를 대신할 뿐 쓰기를 못 한다. refresh 는
UPDATE LAST_SESSION_REFRESH를 하므로 캐시가 있어도 실패한다. up은 이 장애를 못 잡는다. 알림은 readiness 와 외부 응답 코드에 걸어야 한다.