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v0.1.6 (#45)

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## What's New?
Performance updates for large capsules, admin panel enhancement and bug fixes

### Envd
- Fixed bug with sandbox metrics calculation
- Page cache drop and balloon inflation to reduce memfile snapshot
- Updated rpc timeout logic for better control
- Added tests

### Admin Panel
- Add/Remove platform admin
- Updated template deletion logic for fine grained permission

### Others
- Minor frontend visual improvement
- Minor bugfixes
- Version bump

Co-authored-by: Tasnim Kabir Sadik <tksadik92@gmail.com>
Reviewed-on: wrenn/wrenn#45
Co-authored-by: pptx704 <rafeed@omukk.dev>
Co-committed-by: pptx704 <rafeed@omukk.dev>
This commit is contained in:
Rafeed M. Bhuiyan
2026-05-13 05:05:35 +00:00
committed by Tasnim Kabir Sadik
parent f5a23c1fa0
commit e3a60a990f
55 changed files with 2042 additions and 238 deletions
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129
internal/sandbox/manager.go
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@ -95,10 +95,10 @@ type snapshotParent struct {
}
// maxDiffGenerations caps how many incremental diff generations we chain
// before falling back to a Full snapshot to collapse the chain. Long diff
// chains increase restore latency and snapshot directory size; a periodic
// Full snapshot resets the counter and produces a clean base.
const maxDiffGenerations = 8
// before merging diffs into a single file. Since UFFD lazy-loads memory
// anyway, we merge on every re-pause to keep exactly 1 diff file per
// snapshot — no accumulated chain, no extra restore overhead.
const maxDiffGenerations = 1
// buildMetadata constructs the metadata map with version information.
func (m *Manager) buildMetadata(envdVersion string) map[string]string {
@ -186,9 +186,12 @@ func (m *Manager) Create(ctx context.Context, sandboxID string, teamID, template
}
// 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 := int64(diskSizeMB) * 1024 * 1024
cowSize := max(int64(diskSizeMB)*1024*1024, originSize)
dmDev, err := devicemapper.CreateSnapshot(dmName, originLoop, cowPath, originSize, cowSize)
if err != nil {
m.loops.Release(baseRootfs)
@ -374,28 +377,43 @@ func (m *Manager) Pause(ctx context.Context, sandboxID string) error {
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, Firecracker PID). Without this, the sampler
// leaks on every successful pause.
m.stopSampler(sb)
// Step 0: Drain in-flight proxy connections before freezing vCPUs.
// Stale TCP state from mid-flight connections causes issues on restore.
sb.connTracker.Drain(2 * time.Second)
slog.Debug("pause: proxy connections drained", "id", sandboxID)
// ── 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)
// Step 0b: Close host-side idle connections to envd. Done before
// PrepareSnapshot so FIN packets propagate to the guest during the
// PrepareSnapshot window (no extra sleep needed).
// Close host-side idle connections to envd so FIN packets propagate
// to the guest kernel before snapshot.
sb.client.CloseIdleConnections()
slog.Debug("pause: envd client idle connections closed", "id", sandboxID)
// Step 0c: Signal envd to quiesce (stop port scanner/forwarder, mark
// connections for post-restore cleanup). The 3s timeout also gives time
// for the FINs from Step 0b to be processed by the guest kernel.
// Best-effort: a failure is logged but does not abort the pause.
// ── 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, 3*time.Second)
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)
@ -404,11 +422,37 @@ func (m *Manager) Pause(ctx context.Context, sandboxID string) error {
}
}()
// ── Step 3: Inflate balloon to reclaim free guest memory ─────────
// Freed pages become zero from FC's perspective, so ProcessMemfile
// skips them → dramatically smaller memfile (e.g. 20GB → 1GB).
func() {
memUsed, err := readEnvdMemUsed(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*2, 256) + 128
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()
// Step 1: Pause the VM (freeze vCPUs).
if err := m.vm.Pause(ctx, sandboxID); err != nil {
sb.connTracker.Reset()
restoreRunning()
return fmt.Errorf("pause VM: %w", err)
}
slog.Debug("pause: VM paused", "id", sandboxID, "elapsed", time.Since(pauseStart))
@ -423,13 +467,23 @@ func (m *Manager) Pause(ctx context.Context, sandboxID string) error {
// resumeOnError unpauses the VM so the sandbox stays usable when a
// post-freeze step fails. If the resume itself fails, the sandbox is
// left frozen — the caller should destroy it. It also resets the
// connection tracker so the sandbox can accept proxy connections again.
// frozen and unrecoverable — destroy it to avoid a zombie.
resumeOnError := func() {
sb.connTracker.Reset()
if err := m.vm.Resume(ctx, sandboxID); err != nil {
slog.Error("failed to resume VM after pause error — sandbox is frozen", "id", sandboxID, "error", err)
// Use a fresh context — the caller's ctx may already be cancelled.
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 2: Take VM state snapshot (snapfile + memfile).
@ -444,6 +498,7 @@ func (m *Manager) Pause(ctx context.Context, sandboxID string) error {
snapshotStart := time.Now()
if err := m.vm.Snapshot(ctx, sandboxID, snapPath, rawMemPath, snapshotType); err != nil {
slog.Error("pause: snapshot failed", "id", sandboxID, "type", snapshotType, "elapsed", time.Since(snapshotStart), "error", err)
warnErr("snapshot dir cleanup error", sandboxID, os.RemoveAll(pauseDir))
resumeOnError()
return fmt.Errorf("create VM snapshot: %w", err)
@ -795,6 +850,12 @@ func (m *Manager) Resume(ctx context.Context, sandboxID string, timeoutSec int,
slog.Warn("post-init failed after resume, metadata files may be stale", "sandbox", sandboxID, "error", err)
}
// Deflate balloon — the snapshot was taken with an inflated balloon to
// reduce memfile size, so restore the guest's full memory allocation.
if err := m.vm.UpdateBalloon(ctx, sandboxID, 0); err != nil {
slog.Debug("resume: balloon deflate failed (non-fatal)", "id", sandboxID, "error", err)
}
// Fetch envd version (best-effort).
envdVersion, _ := client.FetchVersion(ctx)
@ -1134,7 +1195,7 @@ func (m *Manager) createFromSnapshot(ctx context.Context, sandboxID string, team
dmName := "wrenn-" + sandboxID
cowPath := filepath.Join(layout.SandboxesDir(m.cfg.WrennDir), fmt.Sprintf("%s.cow", sandboxID))
cowSize := int64(diskSizeMB) * 1024 * 1024
cowSize := max(int64(diskSizeMB)*1024*1024, originSize)
dmDev, err := devicemapper.CreateSnapshot(dmName, originLoop, cowPath, originSize, cowSize)
if err != nil {
source.Close()
@ -1235,6 +1296,11 @@ func (m *Manager) createFromSnapshot(ctx context.Context, sandboxID string, team
slog.Warn("post-init failed after template restore, metadata files 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)
@ -1720,12 +1786,12 @@ func (m *Manager) startSampler(sb *sandboxState) {
go m.samplerLoop(ctx, sb, fcPID, sb.VCPUs, initialCPU)
}
// samplerLoop samples /proc metrics at 500ms intervals.
// samplerLoop samples metrics at 1s intervals.
// lastCPU is goroutine-local to avoid shared-state races.
func (m *Manager) samplerLoop(ctx context.Context, sb *sandboxState, fcPID, vcpus int, lastCPU cpuStat) {
defer close(sb.samplerDone)
ticker := time.NewTicker(500 * time.Millisecond)
ticker := time.NewTicker(1 * time.Second)
defer ticker.Stop()
clkTck := 100.0 // sysconf(_SC_CLK_TCK), almost always 100 on Linux
@ -1758,8 +1824,11 @@ func (m *Manager) samplerLoop(ctx context.Context, sb *sandboxState, fcPID, vcpu
cpuInitialized = true
}
// Memory: VmRSS of the Firecracker process.
memBytes, _ := readMemRSS(fcPID)
// Memory: guest-reported used memory from envd /metrics.
// VmRSS of the Firecracker 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(sb.client)
// Disk: allocated bytes of the CoW sparse file.
var diskBytes int64