1
0
forked from wrenn/wrenn
Files
wrenn-releases/internal/sandbox/manager.go
pptx704 124e097e23 refactor: eliminate DRY violations across control plane and host agent
Extract shared helpers to consolidate repeated patterns:
- requireRunningSandbox: sandbox lookup + running check (10 call sites)
- upgradeAndAuthenticate: WS upgrade + JWT/API-key auth (3 handlers)
- updateLastActive: last_active_at update with background context (5 sites)
- attachCowAndCreate: cow loop attach + dmsetup create (devicemapper)
- issueRegistrationToken: token gen + Redis + audit (host service)
- ErrNotFound sentinel: replaces string matching in hostagent server

Also merges duplicate wsProcessOut/wsOutMsg types into one.

Net: -208 lines, zero behavior change.
2026-05-17 02:03:06 +06:00

1822 lines
58 KiB
Go

package sandbox
import (
"context"
"errors"
"fmt"
"log/slog"
"net"
"os"
"os/exec"
"path/filepath"
"sync"
"time"
"github.com/jackc/pgx/v5/pgtype"
"git.omukk.dev/wrenn/wrenn/internal/devicemapper"
"git.omukk.dev/wrenn/wrenn/internal/envdclient"
"git.omukk.dev/wrenn/wrenn/internal/layout"
"git.omukk.dev/wrenn/wrenn/internal/models"
"git.omukk.dev/wrenn/wrenn/internal/network"
"git.omukk.dev/wrenn/wrenn/internal/snapshot"
"git.omukk.dev/wrenn/wrenn/internal/vm"
"git.omukk.dev/wrenn/wrenn/pkg/id"
envdpb "git.omukk.dev/wrenn/wrenn/proto/envd/gen"
)
// ErrNotFound is returned when a sandbox is not present in the in-memory map.
var ErrNotFound = errors.New("sandbox not found")
// Config holds the paths and defaults for the sandbox manager.
type Config struct {
WrennDir string // root directory (e.g. /var/lib/wrenn); all sub-paths derived via layout package
EnvdTimeout time.Duration
DefaultRootfsSizeMB int // target size for template rootfs images; 0 → DefaultDiskSizeMB
// Resolved at startup by the host agent.
KernelPath string // path to the latest vmlinux-x.y.z
KernelVersion string // semver extracted from filename
VMMBin string // path to the cloud-hypervisor binary
VMMVersion string // semver from cloud-hypervisor --version
AgentVersion string // host agent version (injected via ldflags)
}
// LifecycleEvent describes an autonomous state change initiated by the agent.
type LifecycleEvent struct {
Event string
SandboxID string
}
// EventSender sends autonomous lifecycle events to the control plane.
type EventSender interface {
SendAsync(event LifecycleEvent)
}
// Manager orchestrates sandbox lifecycle: VM, network, filesystem, envd.
type Manager struct {
cfg Config
vm *vm.Manager
slots *network.SlotAllocator
loops *devicemapper.LoopRegistry
mu sync.RWMutex
boxes map[string]*sandboxState
stopCh chan struct{}
autoPausedMu sync.Mutex
autoPausedIDs []string
// onDestroy is called with the sandbox ID after cleanup completes.
// Used by ProxyHandler to evict cached reverse proxies.
onDestroy func(sandboxID string)
// eventSender sends autonomous lifecycle events (auto-pause, auto-destroy)
// to the CP via HTTP callback. Optional — nil means events are only
// propagated through the HostMonitor reconciler.
eventSender EventSender
}
// SetOnDestroy registers a callback invoked after each sandbox is cleaned up.
func (m *Manager) SetOnDestroy(fn func(sandboxID string)) {
m.onDestroy = fn
}
// SetEventSender registers the callback sender for autonomous lifecycle events.
func (m *Manager) SetEventSender(sender EventSender) {
m.eventSender = sender
}
// sandboxState holds the runtime state for a single sandbox.
type sandboxState struct {
models.Sandbox
lifecycleMu sync.Mutex // serializes Pause/Destroy/Resume on this sandbox
slot *network.Slot
client *envdclient.Client
connTracker *ConnTracker // tracks in-flight proxy connections for pre-pause drain
dmDevice *devicemapper.SnapshotDevice
baseImagePath string // path to the base template rootfs (for loop registry release)
// Metrics sampling state.
vmmPID int // VMM process PID (child of unshare wrapper)
ring *metricsRing // tiered ring buffers for CPU/mem/disk metrics
samplerCancel context.CancelFunc // cancels the per-sandbox sampling goroutine
samplerDone chan struct{} // closed when the sampling goroutine exits
}
// buildMetadata constructs the metadata map with version information.
func (m *Manager) buildMetadata(envdVersion string) map[string]string {
meta := map[string]string{
"kernel_version": m.cfg.KernelVersion,
"vmm_version": m.cfg.VMMVersion,
"agent_version": m.cfg.AgentVersion,
}
if envdVersion != "" {
meta["envd_version"] = envdVersion
}
return meta
}
// resolveKernelPath returns the kernel path for the given version hint.
// If the exact version exists on disk, it is used. Otherwise, falls back to
// the latest kernel (m.cfg.KernelPath).
func (m *Manager) resolveKernelPath(versionHint string) string {
if versionHint == "" {
return m.cfg.KernelPath
}
exact := layout.KernelPathVersioned(m.cfg.WrennDir, versionHint)
if _, err := os.Stat(exact); err == nil {
return exact
}
slog.Warn("requested kernel version not found, using latest",
"requested", versionHint, "latest", m.cfg.KernelVersion)
return m.cfg.KernelPath
}
// New creates a new sandbox manager.
func New(cfg Config) *Manager {
if cfg.EnvdTimeout == 0 {
cfg.EnvdTimeout = 30 * time.Second
}
return &Manager{
cfg: cfg,
vm: vm.NewManager(),
slots: network.NewSlotAllocator(),
loops: devicemapper.NewLoopRegistry(),
boxes: make(map[string]*sandboxState),
stopCh: make(chan struct{}),
}
}
// Create boots a new sandbox: clone rootfs, set up network, start VM, wait for envd.
// If sandboxID is empty, a new ID is generated.
func (m *Manager) Create(ctx context.Context, sandboxID string, teamID, templateID pgtype.UUID, vcpus, memoryMB, timeoutSec, diskSizeMB int) (*models.Sandbox, error) {
if sandboxID == "" {
sandboxID = id.FormatSandboxID(id.NewSandboxID())
}
if vcpus <= 0 {
vcpus = 1
}
if memoryMB <= 0 {
memoryMB = 512
}
if diskSizeMB <= 0 {
diskSizeMB = 5120 // 5 GB default
}
// Check if template refers to a CH snapshot (has config.json).
tmplDir := layout.TemplateDir(m.cfg.WrennDir, teamID, templateID)
if _, err := os.Stat(filepath.Join(tmplDir, snapshot.CHConfigFile)); err == nil {
return m.createFromSnapshot(ctx, sandboxID, teamID, templateID, vcpus, memoryMB, timeoutSec, diskSizeMB)
}
// Resolve base rootfs image.
baseRootfs := layout.TemplateRootfs(m.cfg.WrennDir, teamID, templateID)
if _, err := os.Stat(baseRootfs); err != nil {
return nil, fmt.Errorf("base rootfs not found at %s: %w", baseRootfs, err)
}
// Acquire shared read-only loop device for the base image.
originLoop, err := m.loops.Acquire(baseRootfs)
if err != nil {
return nil, fmt.Errorf("acquire loop device: %w", err)
}
originSize, err := devicemapper.OriginSizeBytes(originLoop)
if err != nil {
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("get origin size: %w", err)
}
// Create dm-snapshot with per-sandbox CoW file.
// CoW must be at least as large as the origin — if every block is
// rewritten, the CoW stores a full copy. Undersized CoW causes
// dm-snapshot invalidation → EIO on all guest I/O.
dmName := "wrenn-" + sandboxID
cowPath := filepath.Join(layout.SandboxesDir(m.cfg.WrennDir), fmt.Sprintf("%s.cow", sandboxID))
cowSize := max(int64(diskSizeMB)*1024*1024, originSize)
dmDev, err := devicemapper.CreateSnapshot(dmName, originLoop, cowPath, originSize, cowSize)
if err != nil {
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("create dm-snapshot: %w", err)
}
// Allocate network slot.
slotIdx, err := m.slots.Allocate()
if err != nil {
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
os.Remove(cowPath)
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("allocate network slot: %w", err)
}
slot := network.NewSlot(slotIdx)
// Set up network.
if err := network.CreateNetwork(slot); err != nil {
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
os.Remove(cowPath)
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("create network: %w", err)
}
// Boot VM — CH gets the dm device path.
vmCfg := vm.VMConfig{
SandboxID: sandboxID,
TemplateID: id.UUIDString(templateID),
KernelPath: m.cfg.KernelPath,
RootfsPath: dmDev.DevicePath,
VCPUs: vcpus,
MemoryMB: memoryMB,
NetworkNamespace: slot.NamespaceID,
TapDevice: slot.TapName,
TapMAC: slot.TapMAC,
GuestIP: slot.GuestIP,
GatewayIP: slot.TapIP,
NetMask: slot.GuestNetMask,
VMMBin: m.cfg.VMMBin,
}
if _, err := m.vm.Create(ctx, vmCfg); err != nil {
warnErr("network cleanup error", sandboxID, network.RemoveNetwork(slot))
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
os.Remove(cowPath)
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("create VM: %w", err)
}
// Wait for envd to be ready.
client := envdclient.New(slot.HostIP.String())
waitCtx, waitCancel := context.WithTimeout(ctx, m.cfg.EnvdTimeout)
defer waitCancel()
if err := client.WaitUntilReady(waitCtx); err != nil {
warnErr("vm destroy error", sandboxID, m.vm.Destroy(context.Background(), sandboxID))
warnErr("network cleanup error", sandboxID, network.RemoveNetwork(slot))
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
os.Remove(cowPath)
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("wait for envd: %w", err)
}
// Fetch envd version (best-effort).
envdVersion, _ := client.FetchVersion(ctx)
now := time.Now()
sb := &sandboxState{
Sandbox: models.Sandbox{
ID: sandboxID,
Status: models.StatusRunning,
TemplateTeamID: teamID.Bytes,
TemplateID: templateID.Bytes,
VCPUs: vcpus,
MemoryMB: memoryMB,
TimeoutSec: timeoutSec,
SlotIndex: slotIdx,
HostIP: slot.HostIP,
RootfsPath: dmDev.DevicePath,
CreatedAt: now,
LastActiveAt: now,
Metadata: m.buildMetadata(envdVersion),
},
slot: slot,
client: client,
connTracker: &ConnTracker{},
dmDevice: dmDev,
baseImagePath: baseRootfs,
}
m.mu.Lock()
m.boxes[sandboxID] = sb
m.mu.Unlock()
m.startSampler(sb)
m.startCrashWatcher(sb)
slog.Info("sandbox created",
"id", sandboxID,
"team_id", teamID,
"template_id", templateID,
"host_ip", slot.HostIP.String(),
"dm_device", dmDev.DevicePath,
)
return &sb.Sandbox, nil
}
// Destroy stops and cleans up a sandbox. If the sandbox is running, its VM,
// network, and rootfs are torn down. Any pause snapshot files are also removed.
func (m *Manager) Destroy(ctx context.Context, sandboxID string) error {
m.mu.Lock()
sb, ok := m.boxes[sandboxID]
if ok {
delete(m.boxes, sandboxID)
}
m.mu.Unlock()
if ok {
// Wait for any in-progress Pause to finish before tearing down resources.
sb.lifecycleMu.Lock()
defer sb.lifecycleMu.Unlock()
m.cleanup(ctx, sb)
}
// Always clean up pause snapshot files (may exist if sandbox was paused).
if err := os.RemoveAll(layout.PauseSnapshotDir(m.cfg.WrennDir, sandboxID)); err != nil {
slog.Warn("snapshot cleanup error", "id", sandboxID, "error", err)
}
if m.onDestroy != nil {
m.onDestroy(sandboxID)
}
slog.Info("sandbox destroyed", "id", sandboxID)
return nil
}
// cleanup tears down all resources for a sandbox.
func (m *Manager) cleanup(ctx context.Context, sb *sandboxState) {
m.stopSampler(sb)
if err := m.vm.Destroy(ctx, sb.ID); err != nil {
slog.Warn("vm destroy error", "id", sb.ID, "error", err)
}
if err := network.RemoveNetwork(sb.slot); err != nil {
slog.Warn("network cleanup error", "id", sb.ID, "error", err)
}
m.slots.Release(sb.SlotIndex)
// Tear down dm-snapshot and release the base image loop device.
if sb.dmDevice != nil {
if err := devicemapper.RemoveSnapshot(context.Background(), sb.dmDevice); err != nil {
slog.Warn("dm-snapshot remove error", "id", sb.ID, "error", err)
}
os.Remove(sb.dmDevice.CowPath)
}
if sb.baseImagePath != "" {
m.loops.Release(sb.baseImagePath)
}
}
// Pause takes a snapshot of a running sandbox, then destroys all resources.
// The sandbox's snapshot files are stored at SnapshotsDir/{sandboxID}/.
// After this call, the sandbox is no longer running but can be resumed.
func (m *Manager) Pause(ctx context.Context, sandboxID string) error {
sb, err := m.get(sandboxID)
if err != nil {
return err
}
// Serialize lifecycle operations on this sandbox to prevent concurrent
// Pause/Destroy calls from corrupting VM state.
sb.lifecycleMu.Lock()
defer sb.lifecycleMu.Unlock()
if sb.Status != models.StatusRunning {
return fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
// Mark sandbox as pausing to block new exec/file/PTY operations.
m.mu.Lock()
sb.Status = models.StatusPausing
m.mu.Unlock()
// restoreRunning reverts state if any pre-freeze step fails.
restoreRunning := func() {
_ = m.vm.UpdateBalloon(context.Background(), sandboxID, 0)
sb.connTracker.Reset()
m.mu.Lock()
sb.Status = models.StatusRunning
m.mu.Unlock()
m.startSampler(sb)
}
// Stop the metrics sampler goroutine before tearing down any resources
// it reads (dm device, VMM PID). Without this, the sampler
// leaks on every successful pause.
m.stopSampler(sb)
// ── Step 1: Isolate from external traffic ─────────────────────────
// Drain in-flight proxy connections (grace period for clean shutdown).
sb.connTracker.Drain(5 * time.Second)
// Force-close any connections that didn't finish during grace period.
sb.connTracker.ForceClose()
slog.Debug("pause: external connections closed", "id", sandboxID)
// Close host-side idle connections to envd so FIN packets propagate
// to the guest kernel before snapshot.
sb.client.CloseIdleConnections()
// ── Step 2: Drop page cache ──────────────────────────────────────
// Signal envd to quiesce: drops page cache, stops port subsystem,
// marks connections for post-restore cleanup. Page cache drop can
// take significant time on large-memory VMs (20GB+).
func() {
prepCtx, prepCancel := context.WithTimeout(ctx, 30*time.Second)
defer prepCancel()
if err := sb.client.PrepareSnapshot(prepCtx); err != nil {
slog.Warn("pause: pre-snapshot quiesce failed (best-effort)", "id", sandboxID, "error", err)
} else {
slog.Debug("pause: envd quiesced", "id", sandboxID)
}
}()
// ── Step 3: Inflate balloon to reclaim free guest memory ─────────
// Freed pages become zero in the snapshot's memory-ranges file.
// CH v52+ writes sparse snapshots natively (SEEK_DATA/SEEK_HOLE).
func() {
memUsed, err := readEnvdMemUsed(ctx, sb.client)
if err != nil {
slog.Debug("pause: could not read guest memory, skipping balloon inflate", "id", sandboxID, "error", err)
return
}
usedMiB := int(memUsed / (1024 * 1024))
keepMiB := max(usedMiB*3/2, 512)
inflateMiB := sb.MemoryMB - keepMiB
if inflateMiB <= 0 {
slog.Debug("pause: not enough free memory for balloon inflate", "id", sandboxID, "used_mib", usedMiB, "total_mib", sb.MemoryMB)
return
}
balloonCtx, balloonCancel := context.WithTimeout(ctx, 10*time.Second)
defer balloonCancel()
if err := m.vm.UpdateBalloon(balloonCtx, sandboxID, inflateMiB); err != nil {
slog.Debug("pause: balloon inflate failed (non-fatal)", "id", sandboxID, "error", err)
return
}
time.Sleep(2 * time.Second)
slog.Info("pause: balloon inflated", "id", sandboxID, "inflate_mib", inflateMiB, "guest_used_mib", usedMiB)
}()
// ── Step 4: Freeze vCPUs ─────────────────────────────────────────
pauseStart := time.Now()
if err := m.vm.Pause(ctx, sandboxID); err != nil {
restoreRunning()
return fmt.Errorf("pause VM: %w", err)
}
slog.Debug("pause: VM paused", "id", sandboxID, "elapsed", time.Since(pauseStart))
// resumeOnError unpauses the VM so the sandbox stays usable when a
// post-freeze step fails. If the resume itself fails, the sandbox is
// frozen and unrecoverable — destroy it to avoid a zombie.
resumeOnError := func() {
resumeCtx, resumeCancel := context.WithTimeout(context.Background(), 30*time.Second)
defer resumeCancel()
if err := m.vm.Resume(resumeCtx, sandboxID); err != nil {
slog.Error("failed to resume VM after pause error — destroying frozen sandbox", "id", sandboxID, "error", err)
m.cleanup(context.Background(), sb)
m.mu.Lock()
delete(m.boxes, sandboxID)
m.mu.Unlock()
if m.onDestroy != nil {
m.onDestroy(sandboxID)
}
return
}
restoreRunning()
}
// ── Step 5: Take CH snapshot ─────────────────────────────────────
// Snapshot to a temp dir first. If the sandbox was previously resumed,
// the old pauseDir still contains memory-ranges that CH's uffd handler
// is lazily paging from. CH refuses to overwrite existing files (EEXIST),
// so we write to a fresh dir and swap after the VM is destroyed.
pauseDir := layout.PauseSnapshotDir(m.cfg.WrennDir, sandboxID)
tmpPauseDir := pauseDir + ".new"
if err := os.RemoveAll(tmpPauseDir); err != nil {
resumeOnError()
return fmt.Errorf("clean temp snapshot dir: %w", err)
}
if err := os.MkdirAll(tmpPauseDir, 0755); err != nil {
resumeOnError()
return fmt.Errorf("create snapshot dir: %w", err)
}
snapshotStart := time.Now()
if err := m.vm.Snapshot(ctx, sandboxID, tmpPauseDir); err != nil {
slog.Error("pause: snapshot failed", "id", sandboxID, "elapsed", time.Since(snapshotStart), "error", err)
warnErr("snapshot dir cleanup error", sandboxID, os.RemoveAll(tmpPauseDir))
resumeOnError()
return fmt.Errorf("create VM snapshot: %w", err)
}
slog.Debug("pause: CH snapshot created", "id", sandboxID, "elapsed", time.Since(snapshotStart))
// ── Step 6: Destroy the VM so CH releases the dm device ──────────
if err := m.vm.Destroy(ctx, sb.ID); err != nil {
slog.Warn("vm destroy error during pause", "id", sb.ID, "error", err)
}
// CH process is dead — uffd handler no longer reads old memory-ranges.
// Replace old snapshot dir with new one.
if err := os.RemoveAll(pauseDir); err != nil {
slog.Warn("pause: failed to remove old snapshot dir", "id", sandboxID, "error", err)
}
if err := os.Rename(tmpPauseDir, pauseDir); err != nil {
warnErr("network cleanup error during pause", sandboxID, network.RemoveNetwork(sb.slot))
m.slots.Release(sb.SlotIndex)
if sb.dmDevice != nil {
warnErr("dm-snapshot remove error during pause", sandboxID, devicemapper.RemoveSnapshot(context.Background(), sb.dmDevice))
os.Remove(sb.dmDevice.CowPath)
}
if sb.baseImagePath != "" {
m.loops.Release(sb.baseImagePath)
}
m.mu.Lock()
delete(m.boxes, sandboxID)
m.mu.Unlock()
return fmt.Errorf("rename snapshot dir: %w", err)
}
// ── Step 7: Remove dm-snapshot and save CoW ──────────────────────
if sb.dmDevice != nil {
if err := devicemapper.RemoveSnapshot(ctx, sb.dmDevice); err != nil {
warnErr("network cleanup error during pause", sandboxID, network.RemoveNetwork(sb.slot))
m.slots.Release(sb.SlotIndex)
warnErr("snapshot dir cleanup error", sandboxID, os.RemoveAll(pauseDir))
m.mu.Lock()
delete(m.boxes, sandboxID)
m.mu.Unlock()
return fmt.Errorf("remove dm-snapshot: %w", err)
}
snapshotCow := snapshot.CowPath(pauseDir, "")
if err := os.Rename(sb.dmDevice.CowPath, snapshotCow); err != nil {
warnErr("snapshot dir cleanup error", sandboxID, os.RemoveAll(pauseDir))
warnErr("network cleanup error during pause", sandboxID, network.RemoveNetwork(sb.slot))
m.slots.Release(sb.SlotIndex)
os.Remove(sb.dmDevice.CowPath)
if sb.baseImagePath != "" {
m.loops.Release(sb.baseImagePath)
}
m.mu.Lock()
delete(m.boxes, sandboxID)
m.mu.Unlock()
return fmt.Errorf("move cow file: %w", err)
}
if err := snapshot.WriteMeta(pauseDir, "", &snapshot.RootfsMeta{
BaseTemplate: sb.baseImagePath,
TemplateID: id.UUIDString(pgtype.UUID{Bytes: sb.TemplateID, Valid: true}),
VCPUs: sb.VCPUs,
MemoryMB: sb.MemoryMB,
}); err != nil {
warnErr("snapshot dir cleanup error", sandboxID, os.RemoveAll(pauseDir))
warnErr("network cleanup error during pause", sandboxID, network.RemoveNetwork(sb.slot))
m.slots.Release(sb.SlotIndex)
if sb.baseImagePath != "" {
m.loops.Release(sb.baseImagePath)
}
m.mu.Lock()
delete(m.boxes, sandboxID)
m.mu.Unlock()
return fmt.Errorf("write rootfs meta: %w", err)
}
}
// ── Step 8: Clean up remaining resources ─────────────────────────
if err := network.RemoveNetwork(sb.slot); err != nil {
slog.Warn("network cleanup error during pause", "id", sb.ID, "error", err)
}
m.slots.Release(sb.SlotIndex)
if sb.baseImagePath != "" {
m.loops.Release(sb.baseImagePath)
}
m.mu.Lock()
delete(m.boxes, sandboxID)
m.mu.Unlock()
slog.Info("sandbox paused", "id", sandboxID, "total_elapsed", time.Since(pauseStart))
return nil
}
// Resume restores a paused sandbox from its CH snapshot.
// CH handles memory restore internally (with on-demand paging).
// The sandbox gets a new network slot.
// Optional defaultUser and defaultEnv are applied via PostInit with
// sandbox_id and template_id so envd picks up the new sandbox's metadata.
func (m *Manager) Resume(ctx context.Context, sandboxID string, timeoutSec int, kernelVersion string, defaultUser string, defaultEnv map[string]string) (*models.Sandbox, error) {
pauseDir := layout.PauseSnapshotDir(m.cfg.WrennDir, sandboxID)
if _, err := os.Stat(pauseDir); err != nil {
return nil, fmt.Errorf("no snapshot found for sandbox %s", sandboxID)
}
// Read rootfs metadata to find the base template image.
meta, err := snapshot.ReadMeta(pauseDir, "")
if err != nil {
return nil, fmt.Errorf("read rootfs meta: %w", err)
}
// Acquire the base image loop device and restore dm-snapshot from saved CoW.
baseImagePath := meta.BaseTemplate
originLoop, err := m.loops.Acquire(baseImagePath)
if err != nil {
return nil, fmt.Errorf("acquire loop device: %w", err)
}
originSize, err := devicemapper.OriginSizeBytes(originLoop)
if err != nil {
m.loops.Release(baseImagePath)
return nil, fmt.Errorf("get origin size: %w", err)
}
// Move CoW file from snapshot dir to sandboxes dir for the running sandbox.
savedCow := snapshot.CowPath(pauseDir, "")
cowPath := filepath.Join(layout.SandboxesDir(m.cfg.WrennDir), fmt.Sprintf("%s.cow", sandboxID))
if err := os.Rename(savedCow, cowPath); err != nil {
m.loops.Release(baseImagePath)
return nil, fmt.Errorf("move cow file: %w", err)
}
rollbackCow := func() {
if err := os.Rename(cowPath, savedCow); err != nil {
slog.Warn("failed to rollback cow file", "src", cowPath, "dst", savedCow, "error", err)
}
}
// Restore dm-snapshot from existing persistent CoW file.
dmName := "wrenn-" + sandboxID
dmDev, err := devicemapper.RestoreSnapshot(ctx, dmName, originLoop, cowPath, originSize)
if err != nil {
m.loops.Release(baseImagePath)
rollbackCow()
return nil, fmt.Errorf("restore dm-snapshot: %w", err)
}
// Allocate network slot.
slotIdx, err := m.slots.Allocate()
if err != nil {
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
rollbackCow()
m.loops.Release(baseImagePath)
return nil, fmt.Errorf("allocate network slot: %w", err)
}
slot := network.NewSlot(slotIdx)
if err := network.CreateNetwork(slot); err != nil {
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
rollbackCow()
m.loops.Release(baseImagePath)
return nil, fmt.Errorf("create network: %w", err)
}
// Restore VM from CH snapshot.
vmCfg := vm.VMConfig{
SandboxID: sandboxID,
TemplateID: meta.TemplateID,
KernelPath: m.resolveKernelPath(kernelVersion),
RootfsPath: dmDev.DevicePath,
NetworkNamespace: slot.NamespaceID,
TapDevice: slot.TapName,
TapMAC: slot.TapMAC,
GuestIP: slot.GuestIP,
GatewayIP: slot.TapIP,
NetMask: slot.GuestNetMask,
VMMBin: m.cfg.VMMBin,
}
if _, err := m.vm.CreateFromSnapshot(ctx, vmCfg, pauseDir); err != nil {
warnErr("network cleanup error", sandboxID, network.RemoveNetwork(slot))
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
rollbackCow()
m.loops.Release(baseImagePath)
return nil, fmt.Errorf("restore VM from snapshot: %w", err)
}
// Wait for envd to be ready.
client := envdclient.New(slot.HostIP.String())
waitCtx, waitCancel := context.WithTimeout(ctx, m.cfg.EnvdTimeout)
if err := client.WaitUntilReady(waitCtx); err != nil {
waitCancel()
warnErr("vm destroy error", sandboxID, m.vm.Destroy(context.Background(), sandboxID))
warnErr("network cleanup error", sandboxID, network.RemoveNetwork(slot))
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
rollbackCow()
m.loops.Release(baseImagePath)
return nil, fmt.Errorf("wait for envd: %w", err)
}
waitCancel()
// PostInit with sandbox_id and template_id so envd sets metadata env vars.
// Fire-and-forget: post-init is non-critical (metadata/env vars), and
// blocking here widens the window for the CP monitor to race against us.
go func() {
initCtx, initCancel := context.WithTimeout(context.Background(), 10*time.Second)
defer initCancel()
if err := client.PostInitWithDefaults(initCtx, defaultUser, defaultEnv, sandboxID, meta.TemplateID); err != nil {
slog.Warn("post-init failed after resume, metadata may be stale", "sandbox", sandboxID, "error", err)
}
}()
// Deflate balloon — the snapshot was taken with an inflated balloon.
if err := m.vm.UpdateBalloon(ctx, sandboxID, 0); err != nil {
slog.Debug("resume: balloon deflate failed (non-fatal)", "id", sandboxID, "error", err)
}
// Wait for balloon deflation to settle. With OnDemand UFFD restore,
// the guest is under severe memory pressure while the balloon is still
// inflated. If the sampler or memory reclaimer runs during this window,
// the resulting page fault storm can make the guest kernel unresponsive.
if meta.MemoryMB > 0 {
threshold := int64(float64(meta.MemoryMB) * 0.80 * 1024 * 1024)
settleCtx, settleCancel := context.WithTimeout(ctx, 10*time.Second)
ticker := time.NewTicker(500 * time.Millisecond)
settled := false
for !settled {
select {
case <-settleCtx.Done():
slog.Warn("resume: balloon deflation did not settle in time", "id", sandboxID)
settled = true
case <-ticker.C:
used, err := readEnvdMemUsed(settleCtx, client)
if err != nil {
continue
}
if used < threshold {
slog.Info("resume: balloon deflation settled", "id", sandboxID, "used_mib", used/(1024*1024))
settled = true
}
}
}
ticker.Stop()
settleCancel()
}
// Fetch envd version (best-effort).
envdVersion, _ := client.FetchVersion(ctx)
vcpus := meta.VCPUs
if vcpus <= 0 {
vcpus = 1
}
memoryMB := meta.MemoryMB
if memoryMB <= 0 {
memoryMB = 512
}
now := time.Now()
sb := &sandboxState{
Sandbox: models.Sandbox{
ID: sandboxID,
Status: models.StatusRunning,
VCPUs: vcpus,
MemoryMB: memoryMB,
TimeoutSec: timeoutSec,
SlotIndex: slotIdx,
HostIP: slot.HostIP,
RootfsPath: dmDev.DevicePath,
CreatedAt: now,
LastActiveAt: now,
Metadata: m.buildMetadata(envdVersion),
},
slot: slot,
client: client,
connTracker: &ConnTracker{},
dmDevice: dmDev,
baseImagePath: baseImagePath,
}
m.mu.Lock()
m.boxes[sandboxID] = sb
m.mu.Unlock()
m.startSampler(sb)
m.startCrashWatcher(sb)
slog.Info("sandbox resumed from snapshot",
"id", sandboxID,
"host_ip", slot.HostIP.String(),
"dm_device", dmDev.DevicePath,
"vcpus", vcpus,
)
return &sb.Sandbox, nil
}
// CreateSnapshot creates a reusable template from a sandbox. Works on both
// running and paused sandboxes. If the sandbox is running, it is paused first.
// The sandbox remains paused after this call (it can still be resumed).
//
// The rootfs is flattened (base + CoW merged) into a new standalone rootfs.ext4
// so the template has no dependency on the original base image. Memory state
// and VM snapshot files are copied as-is.
func (m *Manager) CreateSnapshot(ctx context.Context, sandboxID string, teamID, templateID pgtype.UUID) (int64, error) {
// If the sandbox is running, pause it first.
if _, err := m.get(sandboxID); err == nil {
if err := m.Pause(ctx, sandboxID); err != nil {
return 0, fmt.Errorf("pause sandbox: %w", err)
}
}
// At this point, pause snapshot files must exist.
pauseDir := layout.PauseSnapshotDir(m.cfg.WrennDir, sandboxID)
if _, err := os.Stat(pauseDir); err != nil {
return 0, fmt.Errorf("no snapshot found for sandbox %s", sandboxID)
}
// Create template directory.
dstDir := layout.TemplateDir(m.cfg.WrennDir, teamID, templateID)
if err := os.MkdirAll(dstDir, 0755); err != nil {
return 0, fmt.Errorf("create template dir: %w", err)
}
// Copy CH snapshot files (config.json, memory-ranges, state.json).
for _, fname := range []string{snapshot.CHConfigFile, snapshot.CHMemRangesFile, snapshot.CHStateFile} {
src := filepath.Join(pauseDir, fname)
dst := filepath.Join(dstDir, fname)
if _, err := os.Stat(src); err != nil {
continue // some files may not exist
}
if err := copyFile(src, dst); err != nil {
warnErr("template dir cleanup error", dstDir, os.RemoveAll(dstDir))
return 0, fmt.Errorf("copy %s: %w", fname, err)
}
}
// Flatten rootfs: temporarily set up dm device from base + CoW, dd to new image.
meta, err := snapshot.ReadMeta(pauseDir, "")
if err != nil {
warnErr("template dir cleanup error", dstDir, os.RemoveAll(dstDir))
return 0, fmt.Errorf("read rootfs meta: %w", err)
}
originLoop, err := m.loops.Acquire(meta.BaseTemplate)
if err != nil {
warnErr("template dir cleanup error", dstDir, os.RemoveAll(dstDir))
return 0, fmt.Errorf("acquire loop device for flatten: %w", err)
}
originSize, err := devicemapper.OriginSizeBytes(originLoop)
if err != nil {
m.loops.Release(meta.BaseTemplate)
warnErr("template dir cleanup error", dstDir, os.RemoveAll(dstDir))
return 0, fmt.Errorf("get origin size: %w", err)
}
// Temporarily restore the dm-snapshot to read the merged view.
cowPath := snapshot.CowPath(pauseDir, "")
tmpDmName := "wrenn-flatten-" + sandboxID
tmpDev, err := devicemapper.RestoreSnapshot(ctx, tmpDmName, originLoop, cowPath, originSize)
if err != nil {
m.loops.Release(meta.BaseTemplate)
warnErr("template dir cleanup error", dstDir, os.RemoveAll(dstDir))
return 0, fmt.Errorf("restore dm-snapshot for flatten: %w", err)
}
// Flatten to new standalone rootfs.
flattenedPath := filepath.Join(dstDir, snapshot.RootfsFileName)
flattenErr := devicemapper.FlattenSnapshot(tmpDev.DevicePath, flattenedPath)
// Always clean up the temporary dm device.
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), tmpDev))
m.loops.Release(meta.BaseTemplate)
if flattenErr != nil {
warnErr("template dir cleanup error", dstDir, os.RemoveAll(dstDir))
return 0, fmt.Errorf("flatten rootfs: %w", flattenErr)
}
sizeBytes, err := snapshot.DirSize(dstDir, "")
if err != nil {
slog.Warn("failed to calculate snapshot size", "error", err)
}
slog.Info("template snapshot created (rootfs flattened)",
"sandbox", sandboxID,
"team_id", teamID,
"template_id", templateID,
"size_bytes", sizeBytes,
)
return sizeBytes, nil
}
// FlattenRootfs stops a running sandbox, flattens its device-mapper CoW
// rootfs into a standalone rootfs.ext4, and cleans up all resources.
// The result is an image-only template (no VM memory/CPU state) stored in
// ImagesDir/{name}/rootfs.ext4.
func (m *Manager) FlattenRootfs(ctx context.Context, sandboxID string, teamID, templateID pgtype.UUID) (int64, error) {
m.mu.Lock()
sb, ok := m.boxes[sandboxID]
if ok {
delete(m.boxes, sandboxID)
}
m.mu.Unlock()
if !ok {
return 0, fmt.Errorf("%w: %s", ErrNotFound, sandboxID)
}
// Flush guest page cache to disk before stopping the VM. Without this,
// files written by the build (e.g. pip-installed packages) may exist in the
// guest's page cache but not yet on the dm block device — flatten would then
// capture 0-byte files.
func() {
syncCtx, cancel := context.WithTimeout(ctx, 10*time.Second)
defer cancel()
if _, err := sb.client.Exec(syncCtx, "/bin/sync"); err != nil {
slog.Warn("flatten: guest sync failed (non-fatal)", "id", sb.ID, "error", err)
}
}()
// Stop the VM but keep the dm device alive for flattening.
m.stopSampler(sb)
if err := m.vm.Destroy(ctx, sb.ID); err != nil {
slog.Warn("vm destroy error during flatten", "id", sb.ID, "error", err)
}
// Release network resources — not needed after VM is stopped.
if err := network.RemoveNetwork(sb.slot); err != nil {
slog.Warn("network cleanup error during flatten", "id", sb.ID, "error", err)
}
m.slots.Release(sb.SlotIndex)
// Create template directory and flatten the dm-snapshot.
flattenDstDir := layout.TemplateDir(m.cfg.WrennDir, teamID, templateID)
if err := os.MkdirAll(flattenDstDir, 0755); err != nil {
m.cleanupDM(sb)
return 0, fmt.Errorf("create template dir: %w", err)
}
outputPath := filepath.Join(flattenDstDir, snapshot.RootfsFileName)
if sb.dmDevice == nil {
m.cleanupDM(sb)
warnErr("template dir cleanup error", flattenDstDir, os.RemoveAll(flattenDstDir))
return 0, fmt.Errorf("sandbox %s has no dm device", sandboxID)
}
if err := devicemapper.FlattenSnapshot(sb.dmDevice.DevicePath, outputPath); err != nil {
m.cleanupDM(sb)
warnErr("template dir cleanup error", flattenDstDir, os.RemoveAll(flattenDstDir))
return 0, fmt.Errorf("flatten rootfs: %w", err)
}
// Clean up dm device and loop device now that flatten is complete.
m.cleanupDM(sb)
// Shrink the flattened image to its minimum size, then re-expand to the
// configured default rootfs size so sandboxes see the full disk from boot.
if out, err := exec.Command("e2fsck", "-fy", outputPath).CombinedOutput(); err != nil {
if exitErr, ok := err.(*exec.ExitError); ok && exitErr.ExitCode() > 1 {
slog.Warn("e2fsck before shrink failed (non-fatal)", "output", string(out), "error", err)
}
}
if out, err := exec.Command("resize2fs", "-M", outputPath).CombinedOutput(); err != nil {
slog.Warn("resize2fs -M failed (non-fatal)", "output", string(out), "error", err)
}
// Re-expand to default rootfs size.
targetMB := m.cfg.DefaultRootfsSizeMB
if targetMB <= 0 {
targetMB = DefaultDiskSizeMB
}
if err := expandImage(outputPath, int64(targetMB)*1024*1024, targetMB); err != nil {
slog.Warn("failed to expand template to default size (non-fatal)", "error", err)
}
sizeBytes, err := snapshot.DirSize(flattenDstDir, "")
if err != nil {
slog.Warn("failed to calculate template size", "error", err)
}
slog.Info("rootfs flattened to image-only template",
"sandbox", sandboxID,
"team_id", teamID,
"template_id", templateID,
"size_bytes", sizeBytes,
)
return sizeBytes, nil
}
// cleanupDM tears down the dm-snapshot device and releases the base image loop device.
func (m *Manager) cleanupDM(sb *sandboxState) {
if sb.dmDevice != nil {
if err := devicemapper.RemoveSnapshot(context.Background(), sb.dmDevice); err != nil {
slog.Warn("dm-snapshot remove error", "id", sb.ID, "error", err)
}
os.Remove(sb.dmDevice.CowPath)
}
if sb.baseImagePath != "" {
m.loops.Release(sb.baseImagePath)
}
}
// DeleteSnapshot removes a snapshot template from disk.
func (m *Manager) DeleteSnapshot(teamID, templateID pgtype.UUID) error {
return os.RemoveAll(layout.TemplateDir(m.cfg.WrennDir, teamID, templateID))
}
// createFromSnapshot creates a new sandbox by restoring from a snapshot template.
// CH handles memory restore internally (with on-demand paging).
// The template's rootfs.ext4 is a flattened standalone image — we create a
// dm-snapshot on top of it just like a normal Create.
func (m *Manager) createFromSnapshot(ctx context.Context, sandboxID string, teamID, templateID pgtype.UUID, vcpus, _, timeoutSec, diskSizeMB int) (*models.Sandbox, error) {
tmplDir := layout.TemplateDir(m.cfg.WrennDir, teamID, templateID)
// Set up dm-snapshot on the template's flattened rootfs.
baseRootfs := filepath.Join(tmplDir, snapshot.RootfsFileName)
originLoop, err := m.loops.Acquire(baseRootfs)
if err != nil {
return nil, fmt.Errorf("acquire loop device: %w", err)
}
originSize, err := devicemapper.OriginSizeBytes(originLoop)
if err != nil {
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("get origin size: %w", err)
}
dmName := "wrenn-" + sandboxID
cowPath := filepath.Join(layout.SandboxesDir(m.cfg.WrennDir), fmt.Sprintf("%s.cow", sandboxID))
cowSize := max(int64(diskSizeMB)*1024*1024, originSize)
dmDev, err := devicemapper.CreateSnapshot(dmName, originLoop, cowPath, originSize, cowSize)
if err != nil {
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("create dm-snapshot: %w", err)
}
// Allocate network.
slotIdx, err := m.slots.Allocate()
if err != nil {
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
os.Remove(cowPath)
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("allocate network slot: %w", err)
}
slot := network.NewSlot(slotIdx)
if err := network.CreateNetwork(slot); err != nil {
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
os.Remove(cowPath)
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("create network: %w", err)
}
// Restore VM from CH snapshot.
vmCfg := vm.VMConfig{
SandboxID: sandboxID,
TemplateID: id.UUIDString(templateID),
KernelPath: m.cfg.KernelPath,
RootfsPath: dmDev.DevicePath,
VCPUs: vcpus,
NetworkNamespace: slot.NamespaceID,
TapDevice: slot.TapName,
TapMAC: slot.TapMAC,
GuestIP: slot.GuestIP,
GatewayIP: slot.TapIP,
NetMask: slot.GuestNetMask,
VMMBin: m.cfg.VMMBin,
}
if _, err := m.vm.CreateFromSnapshot(ctx, vmCfg, tmplDir); err != nil {
warnErr("network cleanup error", sandboxID, network.RemoveNetwork(slot))
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
os.Remove(cowPath)
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("restore VM from snapshot: %w", err)
}
// Wait for envd.
client := envdclient.New(slot.HostIP.String())
waitCtx, waitCancel := context.WithTimeout(ctx, m.cfg.EnvdTimeout)
if err := client.WaitUntilReady(waitCtx); err != nil {
waitCancel()
warnErr("vm destroy error", sandboxID, m.vm.Destroy(context.Background(), sandboxID))
warnErr("network cleanup error", sandboxID, network.RemoveNetwork(slot))
m.slots.Release(slotIdx)
warnErr("dm-snapshot remove error", sandboxID, devicemapper.RemoveSnapshot(context.Background(), dmDev))
os.Remove(cowPath)
m.loops.Release(baseRootfs)
return nil, fmt.Errorf("wait for envd: %w", err)
}
waitCancel()
// PostInit with sandbox_id and template_id so envd sets metadata.
initCtx, initCancel := context.WithTimeout(ctx, m.cfg.EnvdTimeout)
defer initCancel()
if err := client.PostInitWithDefaults(initCtx, "", nil, sandboxID, id.UUIDString(templateID)); err != nil {
slog.Warn("post-init failed after template restore, metadata may be stale", "sandbox", sandboxID, "error", err)
}
// Deflate balloon — template snapshot was taken with an inflated balloon.
if err := m.vm.UpdateBalloon(ctx, sandboxID, 0); err != nil {
slog.Debug("create-from-snapshot: balloon deflate failed (non-fatal)", "id", sandboxID, "error", err)
}
// Fetch envd version (best-effort).
envdVersion, _ := client.FetchVersion(ctx)
now := time.Now()
sb := &sandboxState{
Sandbox: models.Sandbox{
ID: sandboxID,
Status: models.StatusRunning,
TemplateTeamID: teamID.Bytes,
TemplateID: templateID.Bytes,
VCPUs: vcpus,
TimeoutSec: timeoutSec,
SlotIndex: slotIdx,
HostIP: slot.HostIP,
RootfsPath: dmDev.DevicePath,
CreatedAt: now,
LastActiveAt: now,
Metadata: m.buildMetadata(envdVersion),
},
slot: slot,
client: client,
connTracker: &ConnTracker{},
dmDevice: dmDev,
baseImagePath: baseRootfs,
}
m.mu.Lock()
m.boxes[sandboxID] = sb
m.mu.Unlock()
m.startSampler(sb)
m.startCrashWatcher(sb)
slog.Info("sandbox created from snapshot",
"id", sandboxID,
"team_id", teamID,
"template_id", templateID,
"host_ip", slot.HostIP.String(),
"dm_device", dmDev.DevicePath,
)
return &sb.Sandbox, nil
}
// Exec runs a command inside a sandbox.
func (m *Manager) Exec(ctx context.Context, sandboxID string, cmd string, args ...string) (*envdclient.ExecResult, error) {
sb, err := m.get(sandboxID)
if err != nil {
return nil, err
}
if sb.Status != models.StatusRunning {
return nil, fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
m.mu.Lock()
sb.LastActiveAt = time.Now()
m.mu.Unlock()
return sb.client.Exec(ctx, cmd, args...)
}
// ExecStream runs a command inside a sandbox and returns a channel of streaming events.
func (m *Manager) ExecStream(ctx context.Context, sandboxID string, cmd string, args ...string) (<-chan envdclient.ExecStreamEvent, error) {
sb, err := m.get(sandboxID)
if err != nil {
return nil, err
}
if sb.Status != models.StatusRunning {
return nil, fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
m.mu.Lock()
sb.LastActiveAt = time.Now()
m.mu.Unlock()
return sb.client.ExecStream(ctx, cmd, args...)
}
// List returns all sandboxes.
func (m *Manager) List() []models.Sandbox {
m.mu.RLock()
defer m.mu.RUnlock()
result := make([]models.Sandbox, 0, len(m.boxes))
for _, sb := range m.boxes {
result = append(result, sb.Sandbox)
}
return result
}
// Get returns a sandbox by ID.
func (m *Manager) Get(sandboxID string) (*models.Sandbox, error) {
sb, err := m.get(sandboxID)
if err != nil {
return nil, err
}
return &sb.Sandbox, nil
}
// GetClient returns the envd client for a sandbox.
func (m *Manager) GetClient(sandboxID string) (*envdclient.Client, error) {
sb, err := m.get(sandboxID)
if err != nil {
return nil, err
}
if sb.Status != models.StatusRunning {
return nil, fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
return sb.client, nil
}
// SetDefaults calls envd's PostInit to configure the default user and
// environment variables for a running sandbox. This is called by the host
// agent after sandbox creation or resume when the template specifies defaults.
func (m *Manager) SetDefaults(ctx context.Context, sandboxID, defaultUser string, defaultEnv map[string]string) error {
if defaultUser == "" && len(defaultEnv) == 0 {
return nil
}
sb, err := m.get(sandboxID)
if err != nil {
return err
}
if sb.Status != models.StatusRunning {
return fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
return sb.client.PostInitWithDefaults(ctx, defaultUser, defaultEnv, "", "")
}
// PtyAttach starts a new PTY process or reconnects to an existing one.
// If cmd is non-empty, starts a new process. If empty, reconnects using tag.
func (m *Manager) PtyAttach(ctx context.Context, sandboxID, tag, cmd string, args []string, cols, rows uint32, envs map[string]string, cwd string) (<-chan envdclient.PtyEvent, error) {
sb, err := m.get(sandboxID)
if err != nil {
return nil, err
}
if sb.Status != models.StatusRunning {
return nil, fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
m.mu.Lock()
sb.LastActiveAt = time.Now()
m.mu.Unlock()
if cmd != "" {
return sb.client.PtyStart(ctx, tag, cmd, args, cols, rows, envs, cwd)
}
return sb.client.PtyConnect(ctx, tag)
}
// PtySendInput sends raw bytes to a PTY process in a sandbox.
func (m *Manager) PtySendInput(ctx context.Context, sandboxID, tag string, data []byte) error {
sb, err := m.get(sandboxID)
if err != nil {
return err
}
if sb.Status != models.StatusRunning {
return fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
m.mu.Lock()
sb.LastActiveAt = time.Now()
m.mu.Unlock()
return sb.client.PtySendInput(ctx, tag, data)
}
// PtyResize updates the terminal dimensions for a PTY process in a sandbox.
func (m *Manager) PtyResize(ctx context.Context, sandboxID, tag string, cols, rows uint32) error {
sb, err := m.get(sandboxID)
if err != nil {
return err
}
if sb.Status != models.StatusRunning {
return fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
return sb.client.PtyResize(ctx, tag, cols, rows)
}
// PtyKill sends SIGKILL to a PTY process in a sandbox.
func (m *Manager) PtyKill(ctx context.Context, sandboxID, tag string) error {
sb, err := m.get(sandboxID)
if err != nil {
return err
}
if sb.Status != models.StatusRunning {
return fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
return sb.client.PtyKill(ctx, tag)
}
// StartBackground starts a background process inside a sandbox.
func (m *Manager) StartBackground(ctx context.Context, sandboxID, tag, cmd string, args []string, envs map[string]string, cwd string) (uint32, error) {
sb, err := m.get(sandboxID)
if err != nil {
return 0, err
}
if sb.Status != models.StatusRunning {
return 0, fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
m.mu.Lock()
sb.LastActiveAt = time.Now()
m.mu.Unlock()
return sb.client.StartBackground(ctx, tag, cmd, args, envs, cwd)
}
// ConnectProcess re-attaches to a running process inside a sandbox.
func (m *Manager) ConnectProcess(ctx context.Context, sandboxID string, pid uint32, tag string) (<-chan envdclient.ExecStreamEvent, error) {
sb, err := m.get(sandboxID)
if err != nil {
return nil, err
}
if sb.Status != models.StatusRunning {
return nil, fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
m.mu.Lock()
sb.LastActiveAt = time.Now()
m.mu.Unlock()
return sb.client.ConnectProcess(ctx, pid, tag)
}
// ListProcesses returns all running processes inside a sandbox.
func (m *Manager) ListProcesses(ctx context.Context, sandboxID string) ([]envdclient.ProcessInfo, error) {
sb, err := m.get(sandboxID)
if err != nil {
return nil, err
}
if sb.Status != models.StatusRunning {
return nil, fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
m.mu.Lock()
sb.LastActiveAt = time.Now()
m.mu.Unlock()
return sb.client.ListProcesses(ctx)
}
// KillProcess sends a signal to a process inside a sandbox.
func (m *Manager) KillProcess(ctx context.Context, sandboxID string, pid uint32, tag string, signal envdpb.Signal) error {
sb, err := m.get(sandboxID)
if err != nil {
return err
}
if sb.Status != models.StatusRunning {
return fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
m.mu.Lock()
sb.LastActiveAt = time.Now()
m.mu.Unlock()
return sb.client.KillProcess(ctx, pid, tag, signal)
}
// AcquireProxyConn atomically looks up a sandbox by ID and registers an
// in-flight proxy connection. Returns the sandbox's host-reachable IP, the
// connection tracker, and true on success. The caller must call
// tracker.Release() when the request completes. Returns zero values and
// false if the sandbox is not found, not running, or is draining for a pause.
func (m *Manager) AcquireProxyConn(sandboxID string) (net.IP, *ConnTracker, bool) {
m.mu.RLock()
sb, ok := m.boxes[sandboxID]
m.mu.RUnlock()
if !ok || sb.Status != models.StatusRunning {
return nil, nil, false
}
if !sb.connTracker.Acquire() {
return nil, nil, false
}
return sb.HostIP, sb.connTracker, true
}
// Ping resets the inactivity timer for a running sandbox.
func (m *Manager) Ping(sandboxID string) error {
m.mu.Lock()
defer m.mu.Unlock()
sb, ok := m.boxes[sandboxID]
if !ok {
return fmt.Errorf("%w: %s", ErrNotFound, sandboxID)
}
if sb.Status != models.StatusRunning {
return fmt.Errorf("sandbox %s is not running (status: %s)", sandboxID, sb.Status)
}
sb.LastActiveAt = time.Now()
return nil
}
// DrainAutoPausedIDs returns and clears the list of sandbox IDs that were
// automatically paused by the TTL reaper since the last call.
func (m *Manager) DrainAutoPausedIDs() []string {
m.autoPausedMu.Lock()
defer m.autoPausedMu.Unlock()
ids := m.autoPausedIDs
m.autoPausedIDs = nil
return ids
}
func (m *Manager) get(sandboxID string) (*sandboxState, error) {
m.mu.RLock()
defer m.mu.RUnlock()
sb, ok := m.boxes[sandboxID]
if !ok {
return nil, fmt.Errorf("%w: %s", ErrNotFound, sandboxID)
}
return sb, nil
}
// StartTTLReaper starts a background goroutine that destroys sandboxes
// that have exceeded their TTL (timeout_sec of inactivity).
func (m *Manager) StartTTLReaper(ctx context.Context) {
go func() {
ticker := time.NewTicker(2 * time.Second)
defer ticker.Stop()
for {
select {
case <-ctx.Done():
return
case <-m.stopCh:
return
case <-ticker.C:
m.reapExpired(ctx)
}
}
}()
}
func (m *Manager) reapExpired(_ context.Context) {
m.mu.RLock()
var expired []string
now := time.Now()
for id, sb := range m.boxes {
if sb.TimeoutSec <= 0 {
continue
}
if sb.Status != models.StatusRunning {
continue
}
if now.Sub(sb.LastActiveAt) > time.Duration(sb.TimeoutSec)*time.Second {
expired = append(expired, id)
}
}
m.mu.RUnlock()
for _, id := range expired {
slog.Info("TTL expired, auto-pausing sandbox", "id", id)
// Use a detached context so that an app shutdown does not cancel
// a pause mid-flight, which would leave the VM frozen without a
// valid snapshot.
pauseCtx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
err := m.Pause(pauseCtx, id)
cancel()
if err != nil {
slog.Warn("TTL auto-pause failed, destroying sandbox", "id", id, "error", err)
if destroyErr := m.Destroy(context.Background(), id); destroyErr != nil {
slog.Warn("TTL destroy after failed pause also failed", "id", id, "error", destroyErr)
} else if m.eventSender != nil {
m.eventSender.SendAsync(LifecycleEvent{
Event: "sandbox.stopped",
SandboxID: id,
})
}
continue
}
m.autoPausedMu.Lock()
m.autoPausedIDs = append(m.autoPausedIDs, id)
m.autoPausedMu.Unlock()
if m.eventSender != nil {
m.eventSender.SendAsync(LifecycleEvent{
Event: "sandbox.auto_paused",
SandboxID: id,
})
}
}
}
// Shutdown destroys all sandboxes, releases loop devices, and stops the TTL reaper.
func (m *Manager) Shutdown(ctx context.Context) {
close(m.stopCh)
m.mu.Lock()
ids := make([]string, 0, len(m.boxes))
for id := range m.boxes {
ids = append(ids, id)
}
m.mu.Unlock()
for _, sbID := range ids {
slog.Info("shutdown: destroying sandbox", "id", sbID)
if err := m.Destroy(ctx, sbID); err != nil {
slog.Warn("shutdown destroy failed", "id", sbID, "error", err)
}
}
m.loops.ReleaseAll()
}
// PauseAll pauses every running sandbox managed by this host agent.
// Called when the host loses connectivity to the control plane to avoid
// leaving running VMs unmanaged. It is best-effort: failures for individual
// sandboxes are logged but do not stop the rest.
func (m *Manager) PauseAll(ctx context.Context) {
m.mu.RLock()
ids := make([]string, 0, len(m.boxes))
for id, sb := range m.boxes {
if sb.Status == models.StatusRunning {
ids = append(ids, id)
}
}
m.mu.RUnlock()
slog.Info("pausing all running sandboxes due to CP connection loss", "count", len(ids))
for _, sbID := range ids {
if err := m.Pause(ctx, sbID); err != nil {
slog.Warn("PauseAll: failed to pause sandbox", "id", sbID, "error", err)
}
}
}
// warnErr logs a warning if err is non-nil. Used for best-effort cleanup
// in error paths where the primary error has already been captured.
func warnErr(msg string, id string, err error) {
if err != nil {
slog.Warn(msg, "id", id, "error", err)
}
}
// startCrashWatcher monitors the VM process for unexpected exits.
// If the process exits while the sandbox is still in m.boxes (i.e. not a
// deliberate Destroy), the sandbox is cleaned up and a sandbox.error event
// is pushed to the control plane.
func (m *Manager) startCrashWatcher(sb *sandboxState) {
v, ok := m.vm.Get(sb.ID)
if !ok {
return
}
go func() {
select {
case <-v.Exited():
case <-m.stopCh:
return
}
// Check if this was a deliberate Destroy/Pause (sandbox already removed
// from boxes, or Pause owns the cleanup).
m.mu.Lock()
_, stillAlive := m.boxes[sb.ID]
if stillAlive && sb.Status == models.StatusPausing {
stillAlive = false
}
if stillAlive {
delete(m.boxes, sb.ID)
}
m.mu.Unlock()
if !stillAlive {
return
}
slog.Error("VM process crashed, cleaning up", "id", sb.ID)
sb.lifecycleMu.Lock()
m.cleanupAfterCrash(sb)
sb.lifecycleMu.Unlock()
if m.onDestroy != nil {
m.onDestroy(sb.ID)
}
if m.eventSender != nil {
m.eventSender.SendAsync(LifecycleEvent{
Event: "sandbox.error",
SandboxID: sb.ID,
})
}
}()
}
// cleanupAfterCrash tears down sandbox resources after a VM crash.
// The VM process is already dead so we skip vm.Destroy and just clean up
// network, device-mapper, and loop devices.
func (m *Manager) cleanupAfterCrash(sb *sandboxState) {
m.stopSampler(sb)
// Remove the VM from the vm.Manager's map (process is already dead).
_ = m.vm.Destroy(context.Background(), sb.ID)
if err := network.RemoveNetwork(sb.slot); err != nil {
slog.Warn("crash cleanup: network error", "id", sb.ID, "error", err)
}
m.slots.Release(sb.SlotIndex)
if sb.dmDevice != nil {
if err := devicemapper.RemoveSnapshot(context.Background(), sb.dmDevice); err != nil {
slog.Warn("crash cleanup: dm-snapshot error", "id", sb.ID, "error", err)
}
os.Remove(sb.dmDevice.CowPath)
}
if sb.baseImagePath != "" {
m.loops.Release(sb.baseImagePath)
}
}
// startSampler resolves the VMM PID and starts a background goroutine
// that samples CPU/mem/disk at 1s intervals into the ring buffer.
// Must be called after the sandbox is registered in m.boxes.
func (m *Manager) startSampler(sb *sandboxState) {
v, ok := m.vm.Get(sb.ID)
if !ok {
slog.Warn("metrics: VM not found, skipping sampler", "id", sb.ID)
return
}
// v.PID() is the cmd.Process.Pid of the "unshare -m -- bash -c script"
// invocation. The exec chain (unshare → bash → ip netns exec → cloud-hypervisor)
// occupies the same PID. v.PID() IS the VMM PID.
vmmPID := v.PID()
sb.vmmPID = vmmPID
sb.ring = newMetricsRing()
ctx, cancel := context.WithCancel(context.Background())
sb.samplerCancel = cancel
sb.samplerDone = make(chan struct{})
// Read initial CPU counters for delta calculation.
// Passed to goroutine as local state — no shared mutation.
initialCPU, err := readCPUStat(vmmPID)
if err != nil {
slog.Warn("metrics: could not read initial CPU stat", "id", sb.ID, "error", err)
}
go m.samplerLoop(ctx, sb, vmmPID, sb.VCPUs, initialCPU)
}
// samplerLoop samples metrics at 1s intervals.
// lastCPU is goroutine-local to avoid shared-state races.
func (m *Manager) samplerLoop(ctx context.Context, sb *sandboxState, vmmPID, vcpus int, lastCPU cpuStat) {
defer close(sb.samplerDone)
ticker := time.NewTicker(1 * time.Second)
defer ticker.Stop()
clkTck := 100.0 // sysconf(_SC_CLK_TCK), almost always 100 on Linux
lastTime := time.Now()
cpuInitialized := lastCPU != (cpuStat{})
for {
select {
case <-ctx.Done():
return
case now := <-ticker.C:
elapsed := now.Sub(lastTime).Seconds()
lastTime = now
// CPU: delta jiffies / (elapsed * CLK_TCK * vcpus) * 100
var cpuPct float64
cur, err := readCPUStat(vmmPID)
if err == nil {
if cpuInitialized && elapsed > 0 && vcpus > 0 {
deltaJiffies := float64((cur.utime + cur.stime) - (lastCPU.utime + lastCPU.stime))
cpuPct = (deltaJiffies / (elapsed * clkTck * float64(vcpus))) * 100.0
if cpuPct > 100.0 {
cpuPct = 100.0
}
if cpuPct < 0 {
cpuPct = 0
}
}
lastCPU = cur
cpuInitialized = true
}
// Memory: guest-reported used memory from envd /metrics.
// VmRSS of the VMM process includes guest page cache and never
// decreases, so we use the guest's own view which reports
// total - available (actual process memory).
memBytes, _ := readEnvdMemUsed(ctx, sb.client)
// Disk: allocated bytes of the CoW sparse file.
var diskBytes int64
if sb.dmDevice != nil {
diskBytes, _ = readDiskAllocated(sb.dmDevice.CowPath)
}
sb.ring.Push(MetricPoint{
Timestamp: now,
CPUPct: cpuPct,
MemBytes: memBytes,
DiskBytes: diskBytes,
})
}
}
}
// stopSampler stops the metrics sampling goroutine and waits for it to exit.
func (m *Manager) stopSampler(sb *sandboxState) {
if sb.samplerCancel != nil {
sb.samplerCancel()
<-sb.samplerDone
sb.samplerCancel = nil
}
}
// GetMetrics returns the ring buffer data for the given range tier.
// Valid ranges: "10m", "2h", "24h".
func (m *Manager) GetMetrics(sandboxID, rangeTier string) ([]MetricPoint, error) {
m.mu.RLock()
sb, ok := m.boxes[sandboxID]
m.mu.RUnlock()
if !ok {
return nil, fmt.Errorf("%w: %s", ErrNotFound, sandboxID)
}
if sb.ring == nil {
return nil, nil
}
// Map the requested range to the appropriate ring tier and time cutoff.
var points []MetricPoint
var cutoff time.Duration
switch rangeTier {
case "5m":
points = sb.ring.Get10m()
cutoff = 5 * time.Minute
case "10m":
points = sb.ring.Get10m()
cutoff = 10 * time.Minute
case "1h":
points = sb.ring.Get2h()
cutoff = 1 * time.Hour
case "2h":
points = sb.ring.Get2h()
cutoff = 2 * time.Hour
case "6h":
points = sb.ring.Get24h()
cutoff = 6 * time.Hour
case "12h":
points = sb.ring.Get24h()
cutoff = 12 * time.Hour
case "24h":
points = sb.ring.Get24h()
cutoff = 24 * time.Hour
default:
return nil, fmt.Errorf("invalid range: %s (valid: 5m, 10m, 1h, 2h, 6h, 12h, 24h)", rangeTier)
}
// Filter points to the requested time window.
threshold := time.Now().Add(-cutoff)
filtered := points[:0:0]
for _, p := range points {
if !p.Timestamp.Before(threshold) {
filtered = append(filtered, p)
}
}
return filtered, nil
}
// FlushMetrics returns all three tier ring buffers, clears the ring, and
// stops the sampler goroutine. Called by the control plane before pause/destroy.
func (m *Manager) FlushMetrics(sandboxID string) (pts10m, pts2h, pts24h []MetricPoint, err error) {
m.mu.RLock()
sb, ok := m.boxes[sandboxID]
m.mu.RUnlock()
if !ok {
return nil, nil, nil, fmt.Errorf("%w: %s", ErrNotFound, sandboxID)
}
m.stopSampler(sb)
if sb.ring == nil {
return nil, nil, nil, nil
}
pts10m, pts2h, pts24h = sb.ring.Flush()
return pts10m, pts2h, pts24h, nil
}
// copyFile copies a regular file from src to dst using streaming I/O.
func copyFile(src, dst string) error {
sf, err := os.Open(src)
if err != nil {
return fmt.Errorf("open %s: %w", src, err)
}
defer sf.Close()
df, err := os.Create(dst)
if err != nil {
return fmt.Errorf("create %s: %w", dst, err)
}
defer df.Close()
if _, err := df.ReadFrom(sf); err != nil {
os.Remove(dst)
return fmt.Errorf("copy %s → %s: %w", src, dst, err)
}
return nil
}