feat(defrag): EtcdDefragPolicy — scheduled EtcdDefrag runs

[Andrey Kolkov (androndo)]

Adds a CronJob-style EtcdDefragPolicy so the operator drives recurring defragmentation itself, instead of relying on an external CronJob/GitOps cron to create EtcdDefrag objects. This is the follow-up flagged as planned in the EtcdDefrag docs.

Stacked on #361 (the EtcdDefrag controller) — base is feat/defrag-and-capacity-metrics. The diff here is the policy kind + its controller; the runs it stamps are the EtcdDefrag from #361. Merge #361 first; GitHub will retarget this to main.

What it does

Reconciles an EtcdDefragPolicy as a scheduler that stamps out EtcdDefrag runs on a cron cadence:

• Schedule — standard five-field cron, evaluated in UTC (a CRON_TZ=<zone> prefix is honoured). On each due tick it creates one EtcdDefrag, owned by the policy (cascades on delete) and labelled with the policy name.
• The stamped run carries the policy's rule and ttlSecondsAfterFinished, then follows all of feat(defrag): EtcdDefrag controller #361's safety rules — per-cluster serialization, the health gate (incl. NOSPACE handling), followers-before-leader. The policy only triggers; it never defragments directly.
• concurrencyPolicy — Forbid (default: skip a tick while a stamped run is still active) or Allow (stamp anyway; EtcdDefrag's own serialization queues it).
• suspend pauses stamping (missed ticks are not backfilled); startingDeadlineSeconds skips a tick already older than the deadline (e.g. after downtime) rather than starting it late; historyLimit trims retained finished runs (the oldest go first), complementing per-run TTL.
• A long backlog after the operator was down is collapsed into a single run, not replayed slot-by-slot.

status.lastScheduleTime anchors the next tick (so a tick is never acted on twice); status.lastSuccessfulTime records the last Complete; status.active lists in-flight runs; an Active condition carries Suspended/InvalidSchedule reasons.

Adds the API type + generated CRD/deepcopy/RBAC; the controller (wired in main.go, watches its owned EtcdDefrags); github.com/robfig/cron/v3 (what k8s CronJob uses). No changes to EtcdCluster/EtcdDefrag behavior.

Usage

apiVersion: etcd-operator.cozystack.io/v1alpha2
kind: EtcdDefragPolicy
metadata:
  name: nightly
  namespace: team-a
spec:
  clusterRef:
    name: etcd
  schedule: "0 3 * * *"        # UTC
  concurrencyPolicy: Forbid
  ttlSecondsAfterFinished: 3600
  historyLimit: 3
  rule:
    freeSpaceAbove: 200Mi
    quotaUsageAbove: 80%
    minReclaim: 32Mi

Tests

• Unit: schedule parsing (UTC forcing, invalid input) and the next-tick math (not-yet-due, most-recent-boundary, backlog collapse).
• Controller-integration (fake client, injected clock): stamps a run when due (owner ref + labels + rule/ttl propagated, lastScheduleTime set); not-due requeues without stamping; suspend reports Suspended; an unparseable schedule reports InvalidSchedule; Forbid skips while a run is active; Allow stamps concurrently; historyLimit GCs the oldest finished runs.

go build / go vet / go test ./... / gofmt green; CRD/RBAC/deepcopy regenerated (codegen-drift clean).

Refs #221.

🤖 Generated with Claude Code

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