Felis/docs/troubleshooting.md

Felis Troubleshooting Checklist

This file is the spec §28 #23 deliverable: a故障排查清单 (troubleshooting checklist) for the failure modes the platform actually produces. Every symptom below is traced to a concrete signal — a status.conditions reason, an HTTP error code, a log string, or a manifest name — so an operator can map what they see to the code path that emitted it.

How to read this document

Each entry is symptom → likely cause → where to look → fix. Signals are graded for how far the in-repo Go test suite proves the behaviour:

• [GO-TESTED] — a hermetic *_test.go exercises this exact path; the string/code is asserted in CI.
• [CODE-ONLY] — the code path and string exist and are real, but no unit test drives them (notably the Velocity Java plugin, which is not compiled or tested in this repo).
• [INTEGRATION-ONLY] — the symptom is produced by the kubelet, kaniko, containerd, Postgres, or the network, not by Felis Go code; you will see it in kubectl describe / pod logs, never in MinecraftServer.status.
• [INERT] — the configuration field exists in the CRD but no controller reads it. Tuning it does nothing. §12 lists the one field this still applies to, alongside the fields that are read and the condition each depends on.

The operator never invents the parent domain; routing identity is spec.subdomain under the deployment zone. Examples below use <root-domain> / registry.<ns>.svc:<port> placeholders rather than any concrete host.

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1. Server is stuck in Starting and never becomes Running

MinecraftServer.status.phase stays Starting. A start that never succeeds is requeued every 5s until one of the two startup budgets expires, then escalated to Failed — StartupTimeout if the pod never passed TCP readiness, ReadinessTimeout if the RCON probe never succeeded. Both default to 300s when spec.startup.timeoutSeconds / spec.startup.readinessTimeoutSeconds are unset or 0, and both are measured from status.startRequestedAt. [GO-TESTED: TestReconcileRunning_StartupTimeoutConvertsToFailed, TestReconcileRunning_ReadinessTimeoutConvertsToFailed.]

So Starting seen once is normal and TestReconcileRunning_RconProbeFailureStaysStarting asserts exactly that — a single failed probe must not flap the phase. Starting seen for longer than the budget means the reconcile loop is not running at all; check the operator's own logs before tuning anything. Either way the underlying cause is diagnosed from pod state, not from MinecraftServer.status.

First, read the condition reason:

kubectl get minecraftserver <name> -o jsonpath='{.status.conditions}'

markStarting writes the same reason to both Ready=False and RconReached=False. The reason is exactly one of:

status.conditions[].reason	Meaning	Requeue
PodNotReady	Pod not TCP-ready yet (status.readyReplicas < 1)	5s
RconSecretUnavailable	RCON secret missing or malformed	10s
RconNotReachable	RCON dial/auth failed	5s

[GO-TESTED for the reason set.]

1a. PodNotReady — pod never goes ready

The operator cannot tell why the pod is not ready; a broken image, an unbound PVC, and a backend that simply has not finished booting all surface as the identical PodNotReady signal. [GO-TESTED that the reason is emitted; [INTEGRATION-ONLY] for the underlying pod cause.] You must drop to the pod:

kubectl get pod -l app.kubernetes.io/name=<name>
kubectl describe pod <pod>     # look at Events + container State

• ImagePullBackOff / ErrImagePull → spec.image is wrong, the tag does not exist, or the registry is unreachable. spec.image is copied verbatim into the container with zero validation by the operator. Fix the image reference, or see §7 (registry reachability) and §6 (build push target).
• PVC Pending → kubectl get pvc -l app.kubernetes.io/name=<name>. A nonexistent spec.storage.storageClassName, or a request larger than any class can satisfy, leaves the PVC unbound. The operator does not error on this (only a malformed quantity errors — §2); it waits in Starting indefinitely. Fix the StorageClass name or capacity. [INTEGRATION-ONLY.]
• Container crash-looping before the readiness port opens → check container logs; this is a backend/entrypoint problem, not a Felis problem.

1b. RconSecretUnavailable — RCON secret missing or malformed

The probe needs the RCON password from spec.rcon.secretRef. The message is the verbatim error: [CODE-ONLY for these branches]

• rcon.secretRef.name and .key are required when rcon is enabled — you enabled spec.rcon.enabled but left secretRef.name or secretRef.key empty.
• secret "<name>" has no key "<key>" — the Secret exists but lacks the named key.

Fix: create the Secret with the referenced key, or correct secretRef. Verify:

kubectl get secret <secretRef.name> -o jsonpath='{.data.<key>}' | base64 -d | wc -c

1c. RconNotReachable — RCON dial or auth failed

The probe is a TCP connect plus RCON auth handshake, then immediate close — no command is ever run; a successful auth IS the entire readiness gate. The message is the verbatim dial error:

• rcon: authentication failed → the password in the Secret does not match the backend's rcon.password. Reconcile the two. [GO-TESTED that this maps to RconNotReachable.]
• connection refused / i/o timeout → the backend has not opened the RCON port yet, RCON is disabled in server.properties, or spec.rcon.port (default 25575) is wrong. [INTEGRATION-ONLY for the live handshake.]

The per-probe timeout is a fixed 5s in code (prober.go:45, shortened further if the reconcile context has a nearer deadline). It is not derived from spec.startup.readinessTimeoutSeconds, which is the deadline for the whole start, not for one probe — see §12.

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2. Server is in Failed

There is exactly one path to PhaseFailed: markFailed(server, "InvalidSpec", err), reached only when the StatefulSet cannot be built. In practice this means a malformed spec.storage.size (an unparseable resource quantity), surfaced as:

invalid storage size "<value>": <parse error>

status.conditions will show Ready=False and Provisioned=False, both with reason InvalidSpec. Fix the quantity (e.g. 10Gi, not 10 GB) and the server leaves Failed on the next reconcile. [GO path is real; the specific branch is [CODE-ONLY] — the reconciler test fixture uses a valid size.]

Two caveats when a server has been in Failed:

• A pod-not-ready or unreachable-RCON server is never Failed; it is Starting (§1). If you see Failed, it is a spec problem, not a runtime one.
• markFailed does not reset status.endpoint. A server that fails after having been Running keeps a stale endpoint.mode=direct. The proxy should treat any non-Running phase as "do not route direct" rather than trusting a lingering direct endpoint (§4).

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3. Players can't join / get sent to the wrong place

Routing is driven by status.endpoint:

• markRunningReady is the only writer of endpoint.mode=direct (address=<game address>), and only while phase=Running and RCON-ready.
• markStarting, markStopping, markStopped all write endpoint.mode=fallback, address=spec.fallbackServer.

So the proxy should route direct only when phase=Running; otherwise it gets a fallback endpoint. [GO-TESTED for the direct/fallback toggle via markRunningReady/markStopped.]

Two pitfalls:

1. spec.fallbackServer is empty → the fallback endpoint address is "", so during Starting/Stopping/Stopped the proxy has no lobby to park the player in. Set spec.fallbackServer to a registered Velocity server name.
2. Stale direct after Failed → see §2; the proxy must not honour a direct endpoint unless phase=Running.

3a. Wake-on-join is refused, slow, or rate-limited

When a player joins a stopped server, the proxy parks them in the fallback and calls the internal wake API. The authorization gate order is autostartPolicy → per-server cooldown → global running cap. Map the API result:

HTTP	Code	Cause	Fix
403	forbidden	autostartPolicy=allowlist and UUID not allowlisted, or ownerOnly and caller is not owner	Add the UUID / claim the server / set autostartPolicy=public
429	(cooldown)	Wake retried within the 30s per-server WakeCooldown	Wait out the cooldown
503	at_capacity	Global MaxRunningServers cap reached	Stop another server or raise the cap

[GO-TESTED: handlers_internal_wake_test.go, cooldown, running-cap shape.] The operator's RCON probe — not the wake call — is the authoritative readiness gate; the proxy polls GET /api/v1/internal/servers/{name}/status every ~2s and teleports when ready=true.

The Velocity-side consumption of these codes (403 → "You're not allowed to start «server»"; 429 → re-queue; other → "Couldn't start … Try again shortly.") lives in the Java plugin and is [CODE-ONLY] — the codes it reacts to are produced by the Go-tested authorizeWakeByUUID / cooldown limiter, so grade the two halves separately.

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4. Routing is disabled even though servers are up (online-mode coupling)

Wake/claim/allowlist semantics trust Mojang-verified online-mode UUIDs. If the proxy runs online-mode=false, those identities are spoofable, so the Velocity plugin refuses to activate routing:

Felis routing DISABLED: the proxy is in offline mode (online-mode=false).
Domain autostart and the allowlist trust Mojang-verified UUIDs; refusing to
route on spoofable identities. /link remains available. Set online-mode=true to
enable routing.

[CODE-ONLY — FelisVelocityPlugin.onProxyInitialize.] /link still works (account binding does not depend on routing), but no domain autostart happens. The summary line prints routing: disabled (offline mode) or (no root-domain set). Fix: set online-mode=true on the proxy, or configure the root domain if the log says no root-domain set.

On the server side, spec.autostartPolicy and spec.onlineMode are documented as only meaningful when the proxy enforces online-mode=true. Setting them does not by itself make an offline proxy safe — the proxy guard is the enforcement point.

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5. Web panel returns 401 / 403 (Zero-Trust / Cloudflare Access)

The external face accepts either a Cloudflare Access JWT (Cf-Access-Jwt-Assertion header) or a local session cookie. The error envelope is always {"error":{"code","message","request_id"}}. [GO-TESTED.]

• 401 unauthorized — not authenticated: no/invalid Access JWT and no valid session. [GO-TESTED.]
• 403 forbidden — authenticated but not permitted (e.g. a non-admin principal hitting an admin route; IsAdmin() requires role=admin and arrival via the admin Access audience/host). [GO-TESTED.]

5a. Every external request 401s on a fresh deploy

The Access verifier is wired fail-closed: Keyfunc (the JWKS key function) is nil until deployment wiring supplies it. With a nil Keyfunc, every JWT verification fails, and startup logs:

felis api: external face fails closed (Access JWKS key function not configured)

[INTEGRATION-ONLY — the live JWKS path is a deployment point.] This is intended: the panel rejects all callers until JWKS is configured. Fix by wiring the Access JWKS key function for cfg.Auth.AccessJWTAud.

5b. Token rejected with audience error

token audience does not include "<aud>"

The JWT's aud claim does not contain the configured cfg.Auth.AccessJWTAud (or the admin audience for admin routes). [GO-TESTED.] Confirm the Access application audience matches cfg.Auth.AccessJWTAud.

Trust-model note for operators: verification is expiration-required + audience + signing-key (JWKS). There is no iss (issuer) check anywhere in the verifier. Trust rests entirely on the audience claim plus the JWKS signing key. When documenting or auditing the trust boundary, do not assume issuer is validated — it is not.

5c. Local-password login fails or is silently rejected

Local sessions use the felis_session cookie (HttpOnly, Secure, SameSite=Lax, 12h TTL, host-only). They are gated by the local_auth_enabled row in platform_settings, read live per request and fail-closed (missing or unparseable → treated as disabled). Symptoms:

• Cookie present but login rejected with local auth disabled → the local_auth_enabled setting is false/absent. A present cookie under disabled local-auth is rejected outright, not fallen through to the JWT path.
• invalid session: … → bad/forged session hash.

Fix: set local_auth_enabled=true in platform_settings if local password auth is intended. [GO-TESTED for the session/QR-login logic.]

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6. Internal API rejects Velocity / proxy callers (service-token)

The internal face (--internal-addr :8081, routes under /api/v1/internal/...) is never Zero-Trust; it authenticates a single service token via Authorization: Bearer <token>, compared in constant time.

In-cluster it is reached through the ClusterIP Service felis-api-internal (port 8081), which is separate from the external NodePort felis-api (443) precisely so the no-Zero-Trust face is never exposed on a node. On the control-plane node the break-glass console reaches it by resolving that Service's ClusterIP and dialing :8081.

• Internal calls fail to connect (not 401) → the felis-api-internal Service is missing or its selector no longer matches the api pods. kubectl -n felis get svc felis-api-internal must show a ClusterIP with 8081; a bare felis-api name serves only 443 and every internal call would hang/refuse.

• All internal calls 401 → the token is unset or wrong. The API reads env FELIS_SERVICE_TOKEN. If unset, startup logs:

  felis api: warning: FELIS_SERVICE_TOKEN unset — internal face will reject all callers
  

  and wires an empty token, which rejects everyone (no bypass). [GO-TESTED for the constant-time compare / empty-token rejection.]

In-cluster, the token's source of truth is the Secret felis-service-token (key token), injected as FELIS_SERVICE_TOKEN on the API Deployment. Fix:

kubectl get secret felis-service-token -o jsonpath='{.data.token}' | base64 -d

Ensure the proxy is configured with the identical value.

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7. Account-link and claim API errors

Codes from handlers_account.go / handlers_internal.go. [GO-TESTED.]

HTTP	Code	When
400	bad_request	Missing mc_uuid, empty code, or invalid auth_source (must be mojang/thirdparty)
400	invalid_code	Link code unknown or expired (10-min TTL, 8-symbol code)
409	already_linked	That MC UUID is already linked to another user
412	not_linked	Claim/owner op by a caller with no verified account link
403	quota_exceeded	Claim would exceed the user's server quota
409	already_claimed	Atomic UPDATE … WHERE owner_id IS NULL affected 0 rows
404	not_found	Unknown server/resource

Flow reminder: the code is minted in-game on the internal face (POST /api/v1/internal/account/link/code, proves the UUID) and verified on the web external face (POST /api/v1/account/link/verify, proves the user). A 409 already_linked rolls the transaction back and preserves the code so a different user can still use it. The claim's race-safety is the single conditional UPDATE under READ COMMITTED — 1 row → 200, 0 rows → 409. The real SQL execution is [INTEGRATION-ONLY] (no sqlmock/dockertest in repo); the handler logic is [GO-TESTED] via an in-memory fake repo.

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8. Image build fails (Kaniko, spec §14/§16)

8a. Build push rejected at submission with 400

Pre-build validation rejects any push target that is not the internal registry:

must target the internal registry "<registry.<ns>.svc:<port>>", not "<your-target>"

[GO-TESTED via the validate gate.] Fix the image reference to push to cfg.Registry.URL (the internal registry — §9).

8b. Build Job's ServiceAccount can do nothing (RBAC "denial" by design)

The build/restore Job SAs (felis-build, felis-restore, namespace felis-build) have no Role and no RoleBinding anywhere — isolation is the absence of permissions (spec §16/§21). If you see the build SA denied a namespaced API operation, that is correct, not a misconfiguration. [GO-TESTED that the rendered manifests give these SAs no Role.] Do not "fix" it by granting the build SA permissions.

8c. Build hangs then fails fetching base image / packages

The build namespace runs a default-deny egress NetworkPolicy (felis-build-egress); the only allowed egress is the package-mirror CIDRs from --package-cidr, which defaults to none (fail-closed, no internet). [GO-TESTED for the netpol shape.] A kaniko run that hangs pulling a base image or OS package from a non-allowlisted host is the egress policy doing its job — the hang/failure text comes from kaniko/containerd and is [INTEGRATION-ONLY]. Fix: add the mirror CIDR via --package-cidr, or pre-stage the base image in the internal registry.

8d. Build reaches Failed phase

reconcileBuilds polls the Job; a Job reaching Failed is surfaced via writeBuildError (JobPhase→Failed). [GO-TESTED for the mapping.] The underlying cause — a kaniko build error or the Trivy CRITICAL-CVE gate failing the build before push (spec §16) — is in the Job's pod logs and is [INTEGRATION-ONLY]. Inspect:

kubectl logs -n felis-build job/<build-job>

8e. Build Pods never start: executor images and air-gapped installs

The build Job runs Kaniko and Trivy from external registries by default (gcr.io/kaniko-project/executor:latest, aquasec/trivy:latest). On a box whose build namespace cannot reach those registries (the egress policy allows only DNS, the internal registry and --package-cidr mirrors — and an air-gapped box has no route at all), the Pods sit in ImagePullBackOff/ErrImagePull and the build stays building until its deadline. Point the overrides at images in the internal registry — the one pull source that survives an image GC (a bare node-containerd import does not: kubelet's image GC collects unused images under disk pressure, and an air-gapped box then has nothing to restore them from) — in felis.toml:

[registry]
url = "registry.felis.svc:5000"
build_namespace = "felis-build"
kaniko_image = "registry.felis.svc:5000/mirror/kaniko-executor:v1.24.0"
trivy_image  = "registry.felis.svc:5000/mirror/trivy:0.74.0"
trivy_db_repository = "registry.felis.svc:5000/mirror/trivy-db:2"
build_cpu_limit = "2"
build_mem_limit = "4Gi"

Mirror the executor images into the registry once. On the node itself, push through the loopback hostPort the registry Deployment binds (docker treats 127.0.0.1 as insecure by default; the installer leaves the daemon stopped, so sudo systemctl start docker first):

docker pull gcr.io/kaniko-project/executor:v1.24.0   # any versions you pin
docker pull aquasec/trivy:0.74.0
docker tag gcr.io/kaniko-project/executor:v1.24.0 127.0.0.1:5000/mirror/kaniko-executor:v1.24.0
docker tag aquasec/trivy:0.74.0                   127.0.0.1:5000/mirror/trivy:0.74.0
docker push 127.0.0.1:5000/mirror/kaniko-executor:v1.24.0
docker push 127.0.0.1:5000/mirror/trivy:0.74.0

From another machine, port-forward the registry instead (kubectl -n felis port-forward svc/registry 5000:5000) and push to localhost:5000/... — the registry keys a repository by the path after the host, so pushes through either door land in the same place the build Pods will pull from.

Put them in both /etc/felis/felis.host.toml (host-side CLI) and /etc/felis/felis.pod.toml (the file rendered into the API's felis-config Secret — the two differ only in the database URL; the setup screens re-render the Secret from the pod file, so edits made only through kubectl on the live Secret are lost at the next reconfigure). A Deployment restart alone is NOT enough — the API Pod mounts the Secret, never the host file. Re-render the Secret from the pod file, then roll felis-api:

kubectl -n felis create secret generic felis-config \
  --from-file=felis.toml=/etc/felis/felis.pod.toml --dry-run=client -o yaml | kubectl apply -f -
kubectl -n felis rollout restart deployment/felis-api

Unset fields keep the defaults.

trivy_db_repository is not optional on an egress-locked box. Trivy fetches its vulnerability DB from mirror.gcr.io/ghcr.io unless told otherwise, and the build egress policy denies those hosts — so the scan step fails closed (failed to download vulnerability DB) and NO build ever completes, even though Kaniko pushed the image. Mirror the DB into the internal registry once:

# On the node (docker treats 127.0.0.1 as insecure by default), or through the
# port-forward above:
#   docker pull mirror.gcr.io/aquasec/trivy-db:2
#   docker tag  mirror.gcr.io/aquasec/trivy-db:2 127.0.0.1:5000/mirror/trivy-db:2
#   docker push 127.0.0.1:5000/mirror/trivy-db:2

The Job's Trivy container already runs with --insecure, so the internal registry's plain HTTP works for the DB pull exactly as it does for the scanned image. Re-mirror the tag periodically (Trivy refreshes the DB several times a day upstream; a stale mirror only means stale CVE data, never a failed gate).

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9. Registry push/pull failures (spec §15)

The in-cluster registry is Deployment/Service/PVC named registry in the control namespace (or --registry-namespace):

• Push/pull target (the exact string to match): registry.<ns>.svc:<port> (port from --registry-port, default 5000; e.g. --felis-image registry.felis.svc:5000/felis:v1). A wrong push URL is caught at build time by the validate gate (§8a, 400). An unreachable registry at runtime (wrong DNS/port, PVC unbound, missing default StorageClass) surfaces as kaniko push or kubelet pull errors — [INTEGRATION-ONLY], not a Felis-emitted string.
• Storage: PVC is RWO, 10Gi, mounted at /var/lib/registry, no storageClassName → binds the cluster default class. If the cluster has no default StorageClass the PVC stays Pending and the registry never starts.
• Node-side pulls: containerd cannot dial the Service VIP (the live stack answered "Empty reply"), so the registry Deployment binds a loopback hostPort (127.0.0.1:<port>) and the installer writes a /etc/rancher/k3s/registries.yaml mirror relaying registry.<ns>.svc:<port> onto it. That pair is what lets kubelet re-pull a garbage-collected image; both halves must survive together (remove either and every pull after an image GC fails).
• Memory: the registry's limit is 2Gi, deliberately larger than the other control-plane pods' 256Mi — a live 475MB-layer push OOM-killed the 256Mi template mid-upload (audit #46). Very large layers need headroom here, not more CPU.
• Selector quirk worth knowing: the registry Service selector is only name + component=registry — it deliberately lacks the part-of=felis-control-plane label, so the registry is invisible to the RCON-peer NetworkPolicy selector. This is intended isolation, not a bug; do not "fix" it by adding the label.

Registry manifest rendering is [GO-TESTED]; actual serving is [CODE-ONLY/INTEGRATION-ONLY].

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10. World reaper: false-deletes and skipped backups (spec §18)

The reaper is a run-once daily CronJob batch, not an operator controller. It reaps a world only when now - last_active_at > 15d (inactive_15d); the 15-day deadline is hard-fixed in code (only warn_before / retention / max_local_bytes are configurable from felis.toml [archive]).

What a "backup" contains

A backup tars the server's ENTIRE data volume — the same volume the server mounts at /data: world folders, server.properties, plugins/mods, configs, jars, libraries, logs and cache, not just the world/ directory. A restore replaces the volume's contents with the archive (files added since the backup are pruned), so a restore also rolls config/plugin changes back. Sizes are dominated by libraries/cache on stock Paper servers (~170MB for a fresh instance before any world growth) — do not size the archive PVC as if only world data were stored.

The backup-before-delete invariant

The reap sequence (all [GO-TESTED] hermetically) preserves the world unless a confirmed, DB-recorded backup exists:

1. ensureCapacity (only if max_local_bytes > 0) → store full ⇒ world preserved (not deleted).
2. Archiver.Archive fails ⇒ world preserved, PVC untouched.
3. InsertBackup (DB) fails ⇒ the orphan archive is deleted, PVC untouched.
4. Only then DeletePVC → ReleaseWorld → Stop (cosmetic) → audit → felis_reaper_worlds_deleted_total++.

So a missing backup never results in a deleted world. [GO-TESTED: TestReapArchiveFailurePreservesWorld, TestReapInsertBackupFailurePreservesWorld, TestReapIdleWorldFullSequence.]

Exemptions (world never reaped)

• spec.reaperExempt=true → skipped entirely (system servers). [GO-TESTED TestReapExemptServerNeverTouched.]
• CRD missing → logs reaper: CRD missing, skipping, skipped.
• Idle ≤ 15d → not yet eligible.

Pre-reap warnings (the warn_before offsets)

An OWNED server inside a warning window gets an email notice (3d/1d before the deadline, warn_before from [archive]) to the owner's verified email — the same [smtp] relay felis-api uses. The warned_3d_at / warned_1d_at stamps record a delivered notice:

• No [smtp] configured (or owner has no verified address): the run logs reaper: warning suppressed — no warner wired / a delivery error and does NOT stamp. Nothing is falsely recorded as sent, and the day SMTP is configured the pending warning can still go out.
• Delivery failure (relay down): logged and retried on the next daily run — bounded by the warning window, since the reap removes the candidate anyway.
• warned= in the run output counts DELIVERED notices, not attempts.

The reaper runs in the minecraft namespace and reads the mirrors of felis-smtp and felis-config there (a secretKeyRef is namespace-local). The installed felis setup's "configure email" screen refreshes both mirrors when it applies, so configuring SMTP after install is enough; a manual edit of the control-namespace Secret alone is not. [GO-TESTED: the delivered/retried/ suppressed matrix in internal/reaper; live-drilled end to end against a local SMTP sink.]

Genuine false-delete risk vectors

• Stale last_active_at. The keep-alive is RecordJoin, called from the internal join-event handler. If join events are not delivered to the API, the activity clock never resets and an actively-played world becomes reap-eligible after 15 days. Verify join events are flowing (§3a) — this is the most important reaper check. [INTEGRATION-ONLY for the live Postgres write.]
• Unowned servers are still reaped. A server with owner_id="" gets no pre-deletion warning (maybeWarn skips unowned), but is still reaped at 15d. [GO-TESTED TestReapUnownedServerStillReaped.] Claim or exempt servers you want to keep.
• DeletePVC is idempotent (missing PVC is not an error), so a re-run will not fail on already-reaped worlds; and Stop failure is only logged, so a reaped world's MinecraftServer may not be flipped to Stopped.

Only TarLocal (tar+gzip) archiving is implemented; VolumeSnapshot/Longhorn backends return not implemented in this build. The live PVC delete / Postgres store paths are [INTEGRATION-ONLY].

Where worlds are read from (hostPath resolution)

The CronJob mounts --worlds-host-path read-only at /worlds; the resolver runs cmd/felis/reaper.resolveWorldDir: it looks for <root>/<pvc>, then for the stock local-path directory <root>/<pv-name>_<ns>_<pvc-name> derived from the live PVC's spec.volumeName (never a glob — a leftover directory of a deleted PV must not stand in for the world the PVC currently binds). Pointing the flag at k3s's storage root (/var/lib/rancher/k3s/storage) is therefore the supported way to enable retention on a stock install. Two deployment facts the resolver cannot fix:

• Permissions. The reaper Pod runs as root and carries DAC_OVERRIDE: worlds are written by the game image's own UID (root for every Paper image we ship), and Paper saves level.dat mode-0600, so any fixed non-root identity (the previous uid-1000 convention, and the ACL setup that went with it) could neither walk the tree nor read the files — every archive failed open …/level.dat: permission denied and the same defect failed on-demand backups/restores. Root is the same identity the game container itself runs as (see the operator's forwarding-init note); DAC_OVERRIDE extends the archive to game images with a different UID. If a world is still preserved while a reap was expected, it is now a different cause: check the run's ERROR logs for the resolver's lstat messages before suspecting permissions.
• Node placement. Multi-node clusters: the world's directory exists only on the node holding its volume, and the CronJob sets no nodeSelector, so add one (single-node starters are pinned implicitly).

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11. Idle auto-stop never fires; player count always shows 0

Both are implemented, and both hang off the same switch: spec.rcon.enabled. Check it first.

kubectl get minecraftserver <name> -o jsonpath='{.spec.rcon.enabled}'

The player tally is a by-product of the RCON readiness probe — prober.go:63 runs list on the same connection that just authenticated, and parseListReply extracts the tally from There are (\d+) of a max of (\d+) players online. With RCON disabled the probe never runs, players keeps its zero value, and markRunningReady (reconciler.go:413) writes that zero into status.players.online. So a permanent 0 means "never sampled", not "nobody online".

Idle auto-stop (reconciler.go:175) reads that same tally, which is why it carries the RCON condition explicitly:

if server.Spec.Rcon.Enabled && server.Spec.Idle.AutoStopEnabled && server.Spec.Idle.EmptySecondsBeforeStop > 0 {

The comment above it says why: with RCON off the zero tally "would read as 'empty' and use to stop a server full of people". So the guard is deliberate — enabling spec.idle.* without RCON is a no-op by design, not a missing feature.

Both fields set and still nothing happens? Then the probe is failing rather than disabled: the server would be stuck in Starting with RconNotReachable (reconciler.go:156), which is §1's symptom, not this one.

This path used to fail even with everything configured correctly, through three stacked defects proven and fixed on a live cluster (auditfix21/22): the emptySince stamp was pruned by a missing CRD status field, a quiescent empty server produced no watch events to re-check the timer, and the Role lacked the minecraftservers:patch grant the stop write needs. If auto-stop ever looks dead again, check these three in order (each is now pinned by a test):

# ① The stamp must persist — should print a timestamp, not an empty string,
#    a few seconds after a server goes Ready with zero players.
kubectl get minecraftserver <name> -o jsonpath='{.status.emptySince}'

# ② The operator must be able to write spec.desiredState (403 in the operator
#    log = missing patch grant on Role felis-operator).
kubectl auth can-i patch minecraftservers -n <ns> --as=system:serviceaccount:<ctl-ns>:felis-operator

# ③ A wake-up must be scheduled: while empty, expect whatever you set
#    as emptySecondsBeforeStop to elapse and the box to flip to Stopped without
#    any external action.

While players are online the operator re-probes on a 30s cadence so it notices the moment the last one leaves; while empty it schedules a wake-up exactly at the deadline. Quiet operator logs on an idle server are normal — the action is the scheduled wake-up, not a stream of reconciles.

Note the reaper's last_active_at (§10) is a different subsystem (Postgres business layer, bumped by join events) — it keeps worlds alive against the reaper, but it does not auto-stop empty running servers.

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12. A configuration field seems to be ignored

Every field below is read by a controller. What varies is the condition that decides whether setting it does anything.

Field	What you might expect	Reality
spec.startup.timeoutSeconds	Start budget before Failed	Read by startupTimedOut (reconciler.go:479), called at :126. 0 or unset falls back to 300s, then markFailed("StartupTimeout")
spec.startup.readinessTimeoutSeconds	First-probe budget	Read by readinessTimedOut (reconciler.go:490), called at :157. 0 or unset falls back to 300s, then markFailed("ReadinessTimeout"). Not to be confused with the prober's own 5s dial timeout (prober.go:45)
spec.idle.autoStopEnabled	Auto-stop empty servers	Read at reconciler.go:175 — but gated on spec.rcon.enabled, since the player tally comes from the RCON probe (§11)
spec.idle.emptySecondsBeforeStop	Empty grace period	Same branch. Must be > 0; the guard treats 0 as "off", not "stop immediately"

Both startup budgets are measured from the same status.startRequestedAt, so readinessTimeoutSeconds is not a budget after pod readiness — it is a deadline for the whole start, applied on the RCON-probe branch.

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13. World PVC survives after I deleted the MinecraftServer

This is expected. The world PVC is a StatefulSet VolumeClaimTemplate. There is no persistentVolumeClaimRetentionPolicy and no finalizer anywhere in the operator. Deleting the MinecraftServer garbage-collects the StatefulSet, but StatefulSet deletion does not cascade to its template PVCs, and nothing else cleans them up. So the world PVC always survives server deletion. The only code that deletes a world PVC is the reaper, and only after a verified backup (§10). To reclaim a world PVC manually:

kubectl get pvc -l app.kubernetes.io/name=<name>
kubectl delete pvc <pvc>      # irreversible — the world is gone

spec.storage.retainOnDelete sat in the CRD and reached no controller. Spec v4.1 §5 asks for it — 「删除:finalizer 清 Service/STS/ConfigMap,PVC 按 retainOnDelete」 — and neither half was ever built: there is no finalizer, and nothing read the field. It was removed rather than implemented, which is a deliberate departure from that line, recorded here because the spec is a frozen document and still says otherwise.

The reasoning is that implementing it buys a second path that deletes a world — one that skips the reaper's verified-backup check — in order to restore a finalizer whose other listed duties (Service, StatefulSet, ConfigMap) ownerReference GC already performs. A CR still carrying the field keeps working: the API server prunes the unknown key on its next write, and nothing above changes, because retention was never conditional in the first place.

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13b. Node runs out of disk: what survives, and how to recover

A full disk is the most destructive failure this stack sees: kubelet evicts game pods (the control plane is protected below), and its image GC then collects images nothing is running. The images have a pull source now — the in-cluster registry — so they come back without an operator re-import; freeing space is what completes the recovery.

Eviction. Every control-plane pod (api, operator, reaper, registry) runs under the BUILT-IN system-cluster-critical PriorityClass (value 2e9). Kubelet's node-pressure eviction refuses to touch those pods — the log shows "Eviction manager: cannot evict a critical pod" for each of them — while game-server pods at the default priority 0 are evicted first. A drill that filled the disk to 1.7G free saw exactly this: login/lobby evicted, the whole control plane still Running (before the fix the same drill evicted the api, operator and registry too, and the image-GC stage below followed). User-defined PriorityClasses cannot substitute: the API caps them at 1e9, below kubelet's critical threshold. The built-in class allows preemption (its policy is fixed), so a control-plane pod that cannot fit may preempt a game pod — deliberate: the management plane must be placeable.

The pressure condition clears slowly. After you free space, the node can stay DiskPressure:True for up to ~5 minutes (--eviction-pressure-transition-period defaults to 5m, to stop the condition flapping); pods that need scheduling wait for it. This is the bulk of the "recovery takes minutes" observation, not a stuck node.

The images may be gone — they come back on their own. If pods were evicted, the kubelet can garbage-collect their images (unused > 2 minutes under imagefs pressure). Every image this platform runs is ALSO hosted in the in-cluster registry: the installer builds each one as registry.<ns>.svc:5000/felis/… and mirrors it there, and the node's containerd is configured (a registries.yaml mirror onto the registry's loopback hostPort) to relay those refs back through it. So a GC'd image is re-pulled on the next attempt with no operator action — delete the stuck pod to force an immediate retry (or wait out the backoff), and the workload converges.

If a pull does NOT come back:

1. Free disk on the node (df -h /var/lib/rancher; the biggest consumers are k3s ctr images ls -q and the world/backup PVCs under /var/lib/rancher/k3s/storage).
2. Check the registry: kubectl -n felis get pods -l app.kubernetes.io/component=registry and, on the node, curl -s http://127.0.0.1:5000/v2/ (expect {}).
3. Check the mirror file: /etc/rancher/k3s/registries.yaml must map registry.felis.svc:5000 to http://127.0.0.1:5000. Missing or changed: re-run the installer (it rewrites the file and restarts k3s only when the content changed).
4. Re-mirror a tag the registry does not have (hand-built images were never pushed): sudo systemctl start docker (the installer leaves the daemon stopped), then docker tag <ref> 127.0.0.1:5000/<repo>:<tag> && docker push 127.0.0.1:5000/<repo>:<tag>.

For an image that is in neither place, the old fallback still stands: re-run the installer (it rebuilds/re-imports from the local Docker store AND mirrors into the registry), or for a single image docker save felis:<tag> | k3s ctr images import -. The Docker store remains a deliberate second copy on the node; treat it as the recovery path, not as free space.

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14. Metrics for diagnosis (spec §23)

All four mandated metrics have real producers; scrape them when triaging:

• felis_servers_total — managed server count.
• felis_start_duration_seconds — histogram, observed once per start when readiness is first reached (ReadySignalAt − StartRequestedAt). A start that never completes (§1) contributes nothing here — absence of observations is itself the signal that starts are hanging.
• felis_image_build_failures_total — increments on build Job failure (§8d).
• felis_reaper_worlds_deleted_total — increments only after a world PVC is actually deleted post-backup (§10); a spike here means worlds crossed the 15d idle line — cross-check that join events are flowing (§10 risk vectors).

Scraping

The series come from two processes:

• felis-operator pod :8080/metrics — felis_servers_total, felis_start_duration_seconds (no Service; scrape pod-scoped, e.g. a PodMonitor targeting port metrics).
• felis-api internal face :8081/metrics (Service felis-api-internal) — felis_image_build_failures_total. Unauthenticated like the probes; ClusterIP-only, and the external face never serves it.
• felis_reaper_worlds_deleted_total is produced inside the one-shot reaper CronJob, which exits long before any scrape interval — without a pushgateway it has no scrape path. Read the reaper Pod log or the world_backups table for deletions instead.

Alert rules

deploy/alerts/ ships ready-made rules: build failures, slow starts, node disk/memory thresholds, and the kubelet DiskPressure condition.

• Plain Prometheus: add felis-alerts.yaml to rule_files. Check and unit-test it standalone with promtool check rules felis-alerts.yaml and promtool test rules felis-alerts_test.yml (the tests pin exactly when each alert fires).
• kube-prometheus-stack / prometheus-operator: kubectl apply -f felis-prometheusrule.yaml (adjust its release: label to your stack's ruleSelector).

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15. Control-plane upgrades, and rolling back a bad one

There is no in-place updater: an upgrade is re-running the installer (curl -fsSL <installer URL> | sudo bash), which rebuilds/re-imports the image and re-applies the bundle. (sudo felis setup is not this path; on a completed install it only opens the config console.) The channel is not persisted across the re-run, so pass FELIS_VERSION_BOOTSTRAP=dev on a host that tracks main. Two properties of the control plane matter when you do:

• Both Deployments use strategy Recreate (single replica, no leader election: two overlapping instances would fight over the same cluster). An upgrade takes the panel/API down for the rollout window — seconds normally, longer if the new image still has to be imported.
• If the new pod cannot start (bad tag, missing image), the installer's rollout wait fails after 180s and prints kubectl describe diagnostics: you see ErrImagePull/ImagePullBackOff there instead of a silent hang.

Roll back with:

kubectl -n felis rollout undo deploy/felis-api
kubectl -n felis rollout status deploy/felis-api

(the same for felis-operator and registry). rollout undo returns to the previous ReplicaSet, whose image is normally still on the node; if the image GC collected it, the registry re-serves it automatically (§13b) for every tag the installer built — only hand-built tags need a manual re-mirror.

Quick reference: symptom → section

Symptom	Section
Stuck Starting, never Running	§1
Starting with PodNotReady (image? PVC? boot?)	§1a
RCON secret/auth/port errors	§1b, §1c
Phase Failed	§2
Players land in lobby / wrong place	§3, §4
Wake refused / rate-limited (403/429/503)	§3a
Routing disabled, offline-mode	§4
Panel 401/403; fails-closed; audience error	§5
Local password login rejected	§5c
Internal callers 401 (service token)	§6
Link/claim 400/409/412/403/404	§7
Build push 400 / SA denied / egress hang / Failed / executor ImagePullBackOff	§8, §8e
Registry push/pull unreachable	§9
World deleted unexpectedly / backup skipped	§10
Idle auto-stop not firing; player count 0	§11
A config field seems ignored	§12
PVC left behind after delete	§13
Node out of disk; pods evicted / ImagePullBackOff	§13b
Which metric to scrape	§14
Upgrade / roll back a bad control-plane image	§15