fix(platform): control plane runs system-cluster-critical, so eviction refuses it (#8)

| 18 | **绑定码并发兑换 500**：`RedeemPlayerBindCode` 无 `FOR UPDATE`（同文件 `VerifyLinkCode` 有），且裸 INSERT。6 路并发同码兑换 → 3×HTTP 500（`users_username_key` 唯一冲突）+ 1×400 + 2×200；跨码并发同 UUID 同样会撞 | 真机四组并发测试 + API 日志 `unmapped error ... duplicate key` | 同码：码行 `FOR UPDATE`（输家干净地 400 invalid_code）；跨码：`INSERT users ... ON CONFLICT (username) DO NOTHING`+重读、`account_links ON CONFLICT (mc_uuid) DO NOTHING`（两路汇聚同一 user）。复测：同码×6=1×200+5×400、双码×2=2×200 同 ID、DB 干净、日志零 unmapped |

| 19 | **reaper CronJob 渲染位置错误，永远无法调度**：`felis manifests` 把 CronJob 渲染到控制 ns，却引用 minecraft ns 的备份 PVC（Pod 不能跨 ns 挂 PVC：真机 `FailedScheduling: persistentvolumeclaim "felis-backups" not found`）；修正 ns 后又发现 ServerAccount 也不能跨 ns 使用（`serviceaccount "felis-reaper" not found`）。而 reaper 的 Role/RoleBinding 本就在 minecraft ns | 真机三层取证（PVC/SA/调度）| CronJob 与 SA、RoleBinding subject 全部移到 `MinecraftNamespace`（提交 `e4f2cff`+`c839454`）。**修复后完整演练通过**（见下） |

| 6 | **默认安装无备份能力 + 回收链路不可达/不可用**：(a) 没有任何环节渲染归档 PVC，`FELIS_BACKUP_PVC` 永远为空 → backup/restore 恒 503；(b) bootstrap 从不下传 reaper 三旗标 → 官方安装路径根本无法启用回收；(c) 即便启用，stock k3s 的 `<root>/<pvc>` 布局不存在，且 k3s storage root 是 `0700 root:root`、reaper pod 以 uid 1000 运行 → 真机 `lstat /worlds/…: permission denied`（fail-closed 跳过，但纯空转）；(d) README 口径（“定时备份”）不实 | 真机全链路：默认渲染 PVC+env → 建服→marker→备份 202→jobs 端点 running→succeeded→改 marker→restore→读回原值 ✅；再建 resolvecheck 世界（20d idle，marker）→ CronJob 手动 Job：`evaluated=2 reaped=1`，归档含 marker、PVC+宿主目录回收、`world_backups` 得 `inactive_15d` 行、servers 行/CR 保留 ✅ | `platform/workloads.go` 渲染归档 PVC（minecraft ns、RWO 10Gi、默认 SC），`felis manifests --backup-pvc` 默认 `felis-backups`（`=` 空为显式关闭），bootstrap 统一下传 env/旗标并写 [archive] local_path；`resolveWorldDir` 新增精确 local-path 目录解析（读 PVC `spec.volumeName`，非 glob，杜绝陈旧 PV 目录顶替）；ReaperRole 增 `pvc:get`；bootstrap 设 `FELIS_WORLDS_HOST_PATH` 时给 uid 1000 授 traverse（setfacl/o+x）；README/故障手册改写。提交 `fd33fd0`+`2b87a5a` |

| 8 | **磁盘打满灾难链**：DiskPressure → kubelet 驱逐控制面（无 PriorityClass 保护）→ 镜像被 GC（无外网、registry 空）→ 全部 ImagePullBackOff；释放后约 8 分钟才恢复调度。恢复依赖人工 `docker save felis:* | k3s ctr images import -`（docker 存储是唯一副本） | 早前真机 drill；本次复核 k3s 默认驱逐顺序 | 控制面（api/operator/reaper/registry）全部挂 `felis-control-plane` PriorityClass（value 1,000,000，`preemptionPolicy: Never`）——节点压力按优先级升序驱逐，游戏 pod（0）先走，控制面留下；镜像 GC 无法用代码根治（air-gap 无回源），新增 troubleshooting §13b 固化恢复路径（重跑安装器重建导入；单镜像可 `docker save | k3s ctr images import -`）。提交见下 |

| 8 | **磁盘打满灾难链**：DiskPressure → kubelet 驱逐控制面（无 PriorityClass 保护）→ 镜像被 GC（无外网、registry 空）→ 全部 ImagePullBackOff；释放后数分钟才恢复调度。恢复依赖人工 `docker save | k3s ctr images import -` | 三轮真机 drill（原缺陷复现 + 两轮修复验证）：①自定义 1e6 类：游戏 pod 先走、控制面随后仍被驱逐（kubelet 日志逐条列出 ranked/evicted），随后镜像被 GC → ErrImagePull；②内建 `system-cluster-critical`（2e9）：填盘至 1.7G free，kubelet 对 felis-api/operator/registry 全部报 **“cannot evict a critical pod”**，三者在整个 DiskPressure 期间保持 Running；游戏 pod（0）被驱逐；③释放磁盘后：`DiskPressure` 经 ~5 分钟（`eviction-pressure-transition-period`）转 False——即“恢复慢”的主因；被 GC 的游戏镜像按 runbook 重导入后 25s 恢复 ✅ | 控制面四类 pod 挂内建 `system-cluster-critical`（用户自定义类值上限 1e9，达不到 2e9 临界阈值；preemption 保留=管理面可调度，已记录权衡）；troubleshooting §13b 固化事件链、5 分钟条件过渡与镜像恢复路径。提交见下 |

## 待决策台账（未修）

the images exist only in the node's containerd (air-gapped by design), so a

GC'd image has no pull source.

Eviction ordering. Kubelet's node-pressure eviction removes pods in ascending

priority. Every control-plane pod (api, operator, reaper, registry) carries the

bundle's `felis-control-plane` PriorityClass (value 1,000,000,

`preemptionPolicy: Never`), while game-server pods run at the default 0 — so a

burst of running servers is evicted first and the control plane keeps serving

status/console until pressure is genuinely extreme. The class never *preempts*:

a scheduling decision will not kill a running game server to restart the api.

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.

But the *game* images can still be GC'd. If game pods were evicted, the kubelet

may garbage-collect their images (unused > 2 minutes under imagefs pressure), and

those pods then sit in `ImagePullBackOff` after recovery — re-import as above

(`docker save felis-limbo:demo felis-lobby:demo | k3s ctr images import -`, then

delete the stuck pods). Verified: both system servers returned to Running in

~25s after the import.

Symptoms of the image-GC stage: pods stuck `ImagePullBackOff`/`ErrImagePull`

with `kubectl describe pod` showing a pull attempt for a tag that plainly

// Deployments and the in-cluster registry (Deployment + Service + PVC), which

// make the SAs and NetworkPolicy peers refer to something real, plus the

// world-archive PVC that backs backup/restore when a backup PVC is named (see

// workloads.go). Workloads also carries the one cluster-scoped object, the

// felis-control-plane PriorityClass (node-pressure eviction shield — a

// PriorityClass is not namespaced by design); everything else is namespaced.

// workloads.go). Every object here is namespaced; the control plane's

// node-pressure eviction shield is the BUILT-IN system-cluster-critical

// PriorityClass the pod templates reference (workloads.go controlPlanePriorityName),

// not an object this bundle renders.

// The reaper CronJob is also part of Workloads, rendered only when the retention

// storage topology is supplied (WorldsHostPath + BackupPVC + ArchiveLocalPath —

// workloads.go documents the gate and the shape-asserted hostPath caveat). The

	appsv1 "k8s.io/api/apps/v1"

	batchv1 "k8s.io/api/batch/v1"

	corev1 "k8s.io/api/core/v1"

	schedulingv1 "k8s.io/api/scheduling/v1"

	"k8s.io/apimachinery/pkg/api/resource"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	"k8s.io/apimachinery/pkg/util/intstr"

// felis-operator Deployment, and the in-cluster registry (Deployment + Service +

// PVC), the world-archive PVC when p.BackupPVC names it (it backs the

// backup/restore Jobs and the reaper), plus the reaper CronJob when

// reaperEnabled(p). Every pod template carries the felis-control-plane

// PriorityClass (controlPlanePriorityClass below), the node-pressure eviction

// shield. FelisImage is required — `felis manifests` enforces it (fail-loud), so

// a rendered bundle always names a concrete image.

// reaperEnabled(p). Every pod template carries the built-in

// system-cluster-critical PriorityClass (controlPlanePriorityName), the

// node-pressure eviction shield. FelisImage is required — `felis manifests`

// enforces it (fail-loud), so a rendered bundle always names a concrete image.

func Workloads(p Params) []Object {

	p = p.withDefaults()

	objs := []Object{

		controlPlanePriorityClass(),

		APIDeployment(p),

		apiService(p),

		apiInternalService(p),

}

// controlPlanePriorityName is the PriorityClass every control-plane workload runs

// under (api, operator, reaper, registry). Node-pressure eviction (a full disk

// being the realistic case on a game box) removes pods in ASCENDING priority, and

// a classless pod is priority 0 — the same as the game servers, which are exactly

// the pods a burst of joins has just filled the node with. A full disk then takes

// the api/operator down too, and recovery needs a human: with no reachable

// registry on an air-gapped box the images are gone, so the fix is a re-run of the

// installer to re-import them. The class is an eviction shield, not a preemption

// lever: PreemptionPolicy=Never, so a busy node never loses a running game server

// merely to schedule the api. Value 1,000,000 sits above every game pod (0) and

// far below the kubelet's system-reserved classes (2,000,000,000).

const (

	controlPlanePriorityName         = "felis-control-plane"

	controlPlanePriorityValue  int32 = 1_000_000

	controlPlanePriorityReason       = "Felis control plane (api/operator/reaper/registry) survives node-pressure eviction before game servers"

)

// controlPlanePriorityClass renders the cluster-scoped PriorityClass the

// control-plane pod templates reference (the ONE cluster-scoped object in the

// bundle; a PriorityClass is not namespaced by design).

func controlPlanePriorityClass() *schedulingv1.PriorityClass {

	never := corev1.PreemptNever

	return &schedulingv1.PriorityClass{

		TypeMeta:         metav1.TypeMeta{APIVersion: "scheduling.k8s.io/v1", Kind: "PriorityClass"},

		ObjectMeta:       metav1.ObjectMeta{Name: controlPlanePriorityName},

		Value:            controlPlanePriorityValue,

		PreemptionPolicy: &never,

		Description:      controlPlanePriorityReason,

	}

}

// under (api, operator, reaper, registry): the BUILT-IN system-cluster-critical,

// not a class we render. Two live findings force it:

//

//   - ordering alone is not enough. With the disk at k3s's eviction threshold

//     (nodefs.available<5%) a drill watched the kubelet evict the game pods first

//     — and then the api, operator and registry too, because evicting them was

//     never what would reclaim the disk. The images live only in the node's

//     containerd (air-gapped), so once their pods were gone the kubelet GC'd them

//     and recovery degenerated into ImagePullBackOff plus a manual re-import.

//   - a class we render cannot reach the critical threshold: user-defined

//     PriorityClasses are capped at 1e9, while kubelet's

//     `IsCriticalPodBasedOnPriority` — and with it the eviction manager's

//     "cannot evict a critical pod" refusal — needs ≥ 2e9. Only the built-in

//     classes carry those values.

//

// system-cluster-critical keeps the panel/console alive through a full-disk

// incident (which is what lets an operator see it and act) and makes the control

// plane schedule before game pods after a reboot. Its preemptionPolicy is

// PreemptLowerPriority (built-in classes fix it; the API rejects a per-pod

// override), so a control-plane pod that cannot fit MAY preempt a game pod:

// accepted deliberately — the management plane must be placeable, and the

// alternative is an unreachable box. Game pods stay at the default 0 and are

// still the first casualties of node pressure.

const controlPlanePriorityName = "system-cluster-critical"

// reaperEnabled reports whether the retention CronJob should render. It needs all

// three storage coordinates: WorldsHostPath (where worlds live, mounted to read

	appsv1 "k8s.io/api/apps/v1"

	batchv1 "k8s.io/api/batch/v1"

	corev1 "k8s.io/api/core/v1"

	schedulingv1 "k8s.io/api/scheduling/v1"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	"k8s.io/apimachinery/pkg/labels"

)

// internal Service must be present or the login pod's felis-api:8081 path is dead.

func TestWorkloads_BundleContents(t *testing.T) {

	objs := Workloads(testParams())

	if len(objs) != 9 {

		t.Fatalf("Workloads returned %d objects, want 9", len(objs))

	if len(objs) != 8 {

		t.Fatalf("Workloads returned %d objects, want 8", len(objs))

	}

	var haveInternalSvc bool

	for _, o := range objs {

}

// TestControlPlanePriorityClass pins the node-pressure eviction shield: every

// control-plane pod template (api/operator/reaper/registry) references the one

// PriorityClass, which outranks the default-0 game pods by eviction order while

// never preempting them, and is the bundle's only cluster-scoped object. Without

// this, a full disk evicts the api alongside the game pods and (no reachable

// registry on an air-gapped box) recovery needs a human re-importing images.

// control-plane pod template (api/operator/reaper/registry) runs under the

// BUILT-IN system-cluster-critical class (value 2e9), at which kubelet's

// eviction manager refuses to evict the pod. A live drill showed the whole

// cascade with plain ordering: disk pressure evicted the game pods and then the

// control plane, whose images (air-gapped, containerd-only) were GC'd →

// ImagePullBackOff plus a manual re-import. User-defined classes are capped at

// 1e9 (API-enforced), so the built-in class is the only way to reach the

// critical threshold.

func TestControlPlanePriorityClass(t *testing.T) {

	objs := Workloads(reaperParams()) // include the reaper CronJob's pod template

	var class *schedulingv1.PriorityClass

	clusterScoped := 0

	deployments, cronJobs := 0, 0

	for _, o := range objs {

		if o.GetNamespace() == "" {

			clusterScoped++

		}

		switch v := o.(type) {

		case *schedulingv1.PriorityClass:

			class = v

		case *appsv1.Deployment:

			deployments++

			if v.Spec.Template.Spec.PriorityClassName != controlPlanePriorityName {

			}

		}

	}

	if class == nil {

		t.Fatal("Workloads must render the control-plane PriorityClass")

	}

	if class.Name != controlPlanePriorityName || class.Value != controlPlanePriorityValue {

		t.Errorf("class = %s/%d, want %s/%d", class.Name, class.Value, controlPlanePriorityName, controlPlanePriorityValue)

	}

	if class.PreemptionPolicy == nil || *class.PreemptionPolicy != corev1.PreemptNever {

		t.Errorf("class preemptionPolicy = %v, want Never (an eviction shield, never a lever against running game servers)", class.PreemptionPolicy)

	}

	if clusterScoped != 1 {

		t.Errorf("bundle has %d cluster-scoped objects, want exactly the PriorityClass", clusterScoped)

	}

	if deployments != 3 || cronJobs != 1 {

		t.Errorf("scanned %d deployments / %d cronjobs, want 3 / 1 — a pod template escaped the class check", deployments, cronJobs)

	}

	// The class must outrank the default game-pod priority (0); equality would make

	// the eviction order nondeterministic between the api and a full game server.

	if controlPlanePriorityValue <= 0 {

		t.Errorf("control-plane priority %d must exceed the default 0 game-pod priority", controlPlanePriorityValue)

	// The name must be the built-in critical class: any custom class is capped at

	// 1e9 by the API server and would be evictable.

	if controlPlanePriorityName != "system-cluster-critical" {

		t.Errorf("control-plane priority class = %q; only the built-in critical classes reach the 2e9 eviction-refusal threshold", controlPlanePriorityName)

	}

}