Comments should say what the setting does and what constrains it. The
blocks added in #542, #544, #545 and #547 had grown into incident
write-ups: measurement runs, prior values, how a problem was found,
what a check used to be. That belongs in commit messages and the wiki,
both of which already carry it.
Trimmed, no behaviour change:
cephcluster.yaml 22 lines -> 6 (cephx rotation)
cephfs-ci.yaml 26 lines -> 7 (why size 2)
prometheusrule-ceph.yaml (CephHealthWarn, 43 -> 13;
CephPoolLostRedundancy, 15 -> 7)
The operative facts are kept: which checks are excluded and why they
cannot clear, that POOL_NO_REDUNDANCY reports blocked maintenance and
not only data risk, and that size 1 needs dedicated OSDs.
The unreplicated CI pools introduced in #542 make every OSD on the
cluster permanently un-restartable.
`ceph osd ok-to-stop` refuses while stopping an OSD would take PGs
offline. A size-1 pool puts every PG on exactly one OSD, so the check
fails for all three:
Error EBUSY: unsafe to stop osd(s) at this time
(20 PGs are or would become offline)
bad_become_inactive: 13.6 13.9 ... 14.1c 14.1d
Pools 13 and 14 are cephfs-ci-metadata and cephfs-ci-data0. The size-2
pools are not implicated — they run min_size 1 and appear under
ok_become_degraded, which is allowed.
Rook gates OSD restarts on that check, so this blocks CephX key
rotation, Ceph upgrades, node drains and reboots, and drive
replacement. It surfaced when #545 deadlocked: Rook retried
ok-to-stop against all three OSDs several times a second and could
never succeed, while `ceph -s` reported 217 pgs active+clean
throughout. Nothing is unhealthy; the restarts are simply refused.
The reasoning in #542 was that unreplicated CI data only risks
in-flight pipelines, since every byte is a fresh git clone. That part
holds. What it missed is that the cost is not scoped to the pool: one
unreplicated pool freezes maintenance for the entire cluster.
Most of #542's saving came from keeping CI churn off `cephfs`, whose
metadataPool is size 3 — that survives this change. Only the second-
order gain from dropping the replica is given up, and cephfs-ci-data0
stores 0 B with cephfs-ci-metadata at 182 MiB, so the backfill is
trivial.
size 1 becomes viable again once these pools sit on OSDs of their own,
where the permanently un-stoppable OSD holds nothing but throwaway
data. That is planned with the retired QLC drives.
Alerting follows the same change:
- POOL_NO_REDUNDANCY is no longer excluded from CephHealthWarn. It was
excluded because cephfs-ci was expected to keep it permanently
active; no pool is unreplicated now, so the exclusion would only
hide a real one losing its replicas.
- CephPoolLostRedundancy drops its cephfs-ci exemption for the same
reason, and its description now states the maintenance consequence,
not just the data-loss one.
- The AUTH_INSECURE_* exclusion is reworded. Calling it
"known-accepted" reads as a decision that the risk is fine; it is a
kernel-blocked remediation (aes256k over the CSI mount path needs
kernel 7.0+, nodes run 6.18).
Refs #542, #545, #527
Ceph v19.2.6 ships the fix for CVE-2025-30156, a CephX authentication
bypass: AES-128-CBC service tickets carry no HMAC and use a hard-coded
IV, so a holder of any low-privilege key can bit-flip a ticket into
cluster-admin in linear time. Upgrading the binaries does not resolve
it — the keys themselves must be rotated to the aes256k cipher.
The cluster is mid-procedure. auth_allowed_ciphers (aes, aes256k),
auth_preferred_cipher (aes256k) and auth_service_cipher (aes256k) are
already set, and the rotating service keys were wiped, but no actual
key rotation has happened: every entity in status.cephx is still
keyGeneration 1 with keyType aes, created under 19.2.3.
Rook automates daemon-key rotation but it is opt-in and defaults to
Disabled, so spec.security.cephx was left empty and nothing rotated.
Rook v1.20.6 and Ceph v19.2.6 are both past the version floor the
feature requires.
Rotating daemon keys clears AUTH_INSECURE_SERVICE_KEY_TYPE, the only
one of the six new checks at ERR severity. That is the operationally
urgent part: Rook skips CephFS and RGW reconciliation entirely while
health is HEALTH_ERR — which is what deadlocked the mds/rgw rollout in
issue #527 — and the check is presently held down only by a mon-side
mute with a finite TTL. When that mute lapses the cluster returns to
HEALTH_ERR and the reconcile freeze comes back.
CSI keys are deliberately left on aes. aes256k over the CSI mount path
requires a host kernel of 7.0 or newer and these nodes run 6.18, so
`aes` must stay in auth_allowed_ciphers for CSI to authenticate at all.
AUTH_INSECURE_CLIENT_KEY_TYPE, AUTH_INSECURE_KEYS_ALLOWED and
AUTH_INSECURE_KEYS_CREATABLE therefore stay raised at WARN until the
nodes run a kernel that supports it.
Rotation restarts most Ceph daemons. With size 2 pools across 3 OSDs
this should be applied deliberately rather than alongside other churn,
and Ceph should reach HEALTH_OK before anything else touches the
cluster.
Refs #527, #528
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
CephHealthWarn alerted on `ceph_health_status == 1`. It has been FIRING since
at least 2026-08-21T00:26Z and cannot clear: four AUTH_INSECURE_* checks are
permanently active from CVE-2025-30156 (#527) and stay that way until Rook
>=1.20.5 lands. A permanently-firing alert reports nothing -- every Ceph
warning since then has been invisible behind it.
This is a pre-existing gap, not a consequence of the cephfs-ci work, though
that work would have added a second permanent cause (POOL_NO_REDUNDANCY, since
the CI pools are size 1 on purpose).
ceph_health_detail exposes each check as its own series, so the alert now fires
on any check that is NOT known-accepted, and names it. Verified against live
data: 5 checks active, 0 unexpected, so it is quiet now and fires the moment
something genuinely new appears.
Excluding POOL_NO_REDUNDANCY wholesale would give something up: that check is
cluster-wide and does not say WHICH pool, so accepting it for cephfs-ci would
equally hide a production pool dropping to one replica. CephPoolLostRedundancy
restores that. There is no pool-size metric, but bytes_used/stored IS the
replication factor -- verified live as replicapool 2, cephfs-data0 2,
cephfs-metadata 3, cephfs-ci-metadata 1.
Both alerts were tested against live data before committing, in BOTH
directions. The positive control matters as much as the negative one: an early
draft used a >1e9 floor which silently excluded the CI pools entirely, so the
expression could not have matched anything. It looked correct precisely because
it returned no results. The control caught it; the floor is now 1e6.
The floor is not what suppresses the near-empty rgw pools. Their ratios are
9-36 because per-object overhead dominates, so they never match `< 1.5`.
6h on CephHealthWarn is unchanged -- Ceph warns for self-clearing conditions
and paging on those trains people to ignore the alert.
description:"The Ceph cluster has held HEALTH_WARN for six hours, so it is not a self-clearing blip. Get the detail with `kubectl -n rook-ceph exec deploy/rook-ceph-tools -- ceph health detail`."
summary:"Ceph health check {{ $labels.name }} active for 6h"
description:"Ceph health check {{ $labels.name }} has been active for six hours, so it is not a self-clearing blip. Only AUTH_INSECURE_* is excluded (kernel-blocked, see #527), so this is a new condition. Detail: `kubectl -n rook-ceph exec deploy/rook-ceph-tools -- ceph health detail`."
- alert:CephPoolLostRedundancy
# Names the pool, which POOL_NO_REDUNDANCY does not.
#
# There is no pool-size metric, but bytes_used/stored IS the
# replication factor. The >1e6 floor drops pools too small to measure
# meaningfully, empty ones included.
#
# No pool is exempt.
expr:|
ceph_pool_bytes_used / ceph_pool_stored < 1.5 and ceph_pool_stored > 1e6
for:30m
labels:
severity:critical
annotations:
summary:"Ceph pool {{ $labels.pool_id }} is running unreplicated"
description:"Pool {{ $labels.pool_id }} has a replication factor below 1.5, meaning a single OSD loss destroys data. No pool is meant to be unreplicated — an unreplicated pool also blocks ALL OSD maintenance cluster-wide, since `ceph osd ok-to-stop` refuses while its PGs would go offline. Check with `kubectl -n rook-ceph exec deploy/rook-ceph-tools -- ceph osd pool ls detail`."
- alert:CephHealthError
# HEALTH_ERR means data availability or redundancy is at risk.
# A SEPARATE CephFS whose only purpose is Woodpecker CI workspaces, with both
# pools at size 1.
# A SEPARATE CephFS whose only purpose is Woodpecker CI workspaces. Each
# pipeline gets a PVC that is created, filled and deleted within ~2 minutes;
# keeping that churn off `cephfs` spares its size-3 metadataPool.
#
# WHY THIS EXISTS
# Woodpecker's Kubernetes backend creates a PVC per pipeline, fills it with a
# checkout plus build output, and deletes it when the pipeline ends. Measured
# 2026-08-21 by polling both pools at 15s (a 5-minute interval misses a whole
# pipeline — its PVC is created, used and deleted inside ~2 minutes):
#
# one pipeline, a single 15s interval: data0 +71.6 MB metadata +8.2 MB
# every interval without a CI pod: data0 ~0 metadata ~0
#
# CI drove essentially all of it. On the shared filesystem that costs
# 71.6x2 + 8.2x3 = ~168 MB of drive writes per pipeline. Here it costs ~80 MB.
#
# WHY size 1 IS CORRECT HERE, HAVING BEEN REJECTED FOR THE MAIN FILESYSTEM
# `cephfs` keeps metadataPool at size 3 because losing it destroys the whole
# filesystem, not the objects on one OSD, and 550 GiB in cephfs-data0 depends
# on it. None of that applies to this filesystem. Every byte in it is a fresh
# git clone; the worst case of total loss is that in-flight pipelines fail and
# get re-run. Replicating throwaway data is the thing being paid for, so it is
# the thing removed.
#
# Losing an OSD takes these PGs offline and kills running pipelines. That is
# not a regression: CI already breaks during Ceph maintenance.
# size 2, not 1: an unreplicated pool makes `ceph osd ok-to-stop` refuse for
# every OSD, blocking all OSD maintenance cluster-wide. size 1 is viable only
# once these pools have OSDs of their own.
apiVersion:ceph.rook.io/v1
kind:CephFilesystem
metadata:
@@ -32,15 +14,11 @@ metadata:
spec:
metadataPool:
replicated:
size:1
# Rook refuses size 1 without this — it is asserting that an unreplicated
# pool is deliberate rather than a typo. It is.
requireSafeReplicaSize:false
size:2
dataPools:
- name:data0
replicated:
size:1
requireSafeReplicaSize:false
size:2
metadataServer:
activeCount:1
# No standby-replay, unlike `cephfs`. A standby exists there so a failed
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