- Change sandbox ID prefix from sb- to cl- (capsule) throughout
- Fix proxy URL regex character class: base36 uses 0-9a-z, not just hex
- Add MMDS V2 config and metadata to VM boot flow so envd can read
WRENN_SANDBOX_ID and WRENN_TEMPLATE_ID from inside the guest
- Pass TemplateID through VMConfig into both fresh and snapshot boot paths
Always use Firecracker Diff snapshots (fast, only changed pages) and
merge diff files at the file level when the generation cap is reached.
The previous approach used Firecracker's Full snapshot type which dumps
all memory to disk and can timeout, losing all snapshot data on failure.
Add snapshot.MergeDiffs() which reads each block from the appropriate
generation's diff file via the header mapping and writes them into a
single consolidated file with a fresh generation-0 header.
Rename ns-{idx} to wrenn-ns-{idx} and veth-{idx} to wrenn-veth-{idx}
to avoid collisions with other tools. Add CleanupStaleNamespaces() at
agent startup to remove orphaned namespaces, veths, iptables rules, and
routes from a previous crash. Lower maxDiffGenerations from 10 to 8 to
prevent Go runtime memory corruption from snapshot/restore drift.
Introduces internal/layout package for centralized path construction,
migrates templates from name-based TEXT primary keys to UUID PKs with
team-scoped directories (WRENN_DIR/images/teams/{team_id}/{template_id}).
The built-in minimal template uses sentinel zero UUIDs. Proto messages
carry team_id + template_id alongside deprecated template name field.
Team deletion now cleans up template files across all hosts.
Snapshot race fix:
- Pre-mark sandbox as "paused" in DB before issuing CreateSnapshot and
PauseSandbox RPCs, preventing the reconciler from marking it "stopped"
during the flatten window when the sandbox is gone from the host
agent's in-memory map but DB still says "running"
- Revert status to "running" on RPC failure
- Check ctx.Err() before writing response to avoid writing to dead
connections when client disconnects during long snapshot operations
Delete auth fix:
- Block non-admin deletion of platform templates (team_id = all-zeros)
at DELETE /v1/snapshots/{name} with 403, preventing file deletion
before the team ownership check fails
Sparse dd:
- Add conv=sparse to dd in FlattenSnapshot so flattened images preserve
sparseness (~200MB actual vs 5GB logical)
Default disk size:
- Change default disk_size_mb from 20GB to 5GB across migration,
manager, service, build, and EnsureImageSizes
- Disable split-button dropdown arrow for platform templates in
dashboard snapshots page (teams cannot delete platform templates)
Disk sizing:
- Add disk_size_mb column to sandboxes table (default 20480 = 20GB)
- Add disk_size_mb to CreateSandboxRequest proto, passed through the
full chain: service → RPC → host agent → sandbox manager → devicemapper
- devicemapper.CreateSnapshot takes separate cowSizeBytes param so the
sparse CoW file can be sized independently from the origin
- EnsureImageSizes() runs at host agent startup: expands any base image
smaller than 20GB via truncate + resize2fs (sparse, no extra physical
disk). Sandboxes then get the full 20GB via fast dm-snapshot path
- FlattenRootfs shrinks output images with resize2fs -M so stored
templates are compact; EnsureImageSizes re-expands on next startup
Admin templates visibility:
- Add GET /v1/admin/templates endpoint listing all templates across teams
- Frontend admin templates page uses listAdminTemplates() instead of
team-scoped listSnapshots()
- Platform templates (team_id = all-zeros UUID) now visible to all teams:
GetTemplateByTeam, ListTemplatesByTeam, ListTemplatesByTeamAndType
queries include platform team_id in WHERE clause
Consolidate 16 migrations into one with UUID columns for all entity
IDs. TEXT is kept only for polymorphic fields (audit_logs.actor_id,
resource_id) and template names. The id package now generates UUIDs
via google/uuid, with Format*/Parse* helpers for the prefixed wire
format (sb-{uuid}, usr-{uuid}, etc.). Auth context, services, and
handlers pass pgtype.UUID internally; conversion to/from prefixed
strings happens at API and RPC boundaries. Adds PlatformTeamID
(all-zeros UUID) for shared resources.
- Use context.Background() with timeout in destroySandbox/failBuild so
cleanup and DB writes survive parent context cancellation on shutdown
- Fix loop device refcount leak in FlattenRootfs when dmDevice is nil
- Replace time.After with time.NewTimer in healthcheck polling to avoid
goroutine leak when healthcheck passes early
- Capture size_bytes from CreateSnapshot/FlattenRootfs RPC responses
instead of hardcoding 0 in the templates table insert
- Avoid leaking internal error details to API clients in build handler
Introduces an end-to-end template building pipeline: admins submit a recipe
(list of shell commands) via the dashboard, a Redis-backed worker pool spins
up a sandbox, executes each command, and produces either a full snapshot
(with healthcheck) or an image-only template (rootfs flattened via a new
FlattenRootfs host-agent RPC). Build progress and per-step logs are persisted
to a new template_builds table and polled by the frontend.
Backend:
- New FlattenRootfs RPC (proto + host agent + sandbox manager)
- BuildService with Redis queue (BLPOP) and configurable worker pool (default 2)
- Admin-only REST endpoints: POST/GET /v1/admin/builds, GET /v1/admin/builds/{id}
- Migration for template_builds table with JSONB logs and recipe columns
- sqlc queries for build CRUD and progress updates
Frontend:
- /admin/templates page with Templates + Builds tabs
- Create Template dialog with recipe textarea, healthcheck, specs
- Build history with expandable per-step logs, status badges, progress bars
- Auto-polling every 3s for active builds
- AdminSidebar updated with Templates nav item
Switch from the envd /init endpoint pushing host time via syscall to
chronyd reading the KVM PTP hardware clock (/dev/ptp0) continuously.
This fixes clock drift between init calls and handles snapshot resume
gracefully.
Changes:
- Add clocksource=kvm-clock kernel boot arg
- Start chronyd in wrenn-init.sh before tini (PHC /dev/ptp0, makestep 1.0 -1)
- Remove clock_settime logic from envd SetData and shouldSetSystemTime
- Remove client.Init() clock sync calls from sandbox manager (3 sites)
- Remove Init() method from envdclient (no longer needed)
- Simplify rootfs scripts: socat/chrony now come from apt in the container
image, only envd/wrenn-init/tini are injected by build scripts
- New detail page at /dashboard/capsules/[id] with Stats and Files tabs
- Stats tab shows capsule info card (status, template, CPU, memory, disk,
started, idle timeout) and two stacked Chart.js charts with live values
- Metrics API client with 10s polling and moving-average smoothing
- Capsule ID in list table is now a clickable link to the detail page
- Layout breadcrumb header (Capsules > sb-xxx) with back navigation
- Fix metrics sampler: use v.PID() directly as Firecracker PID since
unshare -m execs (not forks) through the bash/ip-netns-exec/firecracker
chain, so all share the same PID. Removes unused findChildPID.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Maps each user-facing range to the appropriate underlying ring buffer
tier and applies a time cutoff filter. No new ring buffers needed —
5m/10m read from the 10m tier, 1h/2h from the 2h tier, 6h/12h/24h
from the 24h tier.
Samples /proc/{fc_pid}/stat (CPU%), /proc/{fc_pid}/status (VmRSS), and
stat() on CoW files at 500ms intervals per running sandbox. Three tiered
ring buffers downsample into 30s and 5min averages for 10min/2h/24h
retention. Metrics are flushed to DB on pause (all tiers) and destroy
(24h only). New GetSandboxMetrics and FlushSandboxMetrics RPCs on the
host agent, proxied through GET /v1/sandboxes/{id}/metrics?range= on
the control plane. Returns live data for running sandboxes, DB data for
paused, and 404 for stopped.
Replaces the hardcoded CP_HOST_AGENT_ADDR single-agent setup with a
DB-driven registration system supporting multiple host agents (BYOC).
Key changes:
- Host agents register via one-time token, receive a 7-day JWT + 60-day
refresh token; heartbeat loop auto-refreshes on 401/403 and pauses all
sandboxes if refresh fails
- HostClientPool: lazy Connect RPC client cache keyed by host ID, replacing
the single static agent client throughout the API and service layers
- RoundRobinScheduler: picks an online host for each new sandbox via
ListActiveHosts; extensible for future scheduling strategies
- HostMonitor (replaces Reconciler): passive heartbeat staleness check marks
hosts unreachable and sandboxes missing after 90s; active reconciliation
per online host restores missing-but-alive sandboxes and stops orphans
- Graceful host delete: returns 409 with affected sandbox list without
?force=true; force-delete destroys sandboxes then evicts pool client
- Snapshot delete broadcasts to all online hosts (templates have no host_id)
- sandbox.Manager.PauseAll: pauses all running VMs on CP connectivity loss
- New migration: host_refresh_tokens table with token rotation (issue-then-
revoke ordering to prevent lockout on mid-rotation crash)
- New sandbox status 'missing' (reversible, unlike 'stopped') and host
status 'unreachable'; both reflected in OpenAPI spec
- Fix: refresh token auth failure now returns 401 (was 400 via generic
'invalid' substring match in serviceErrToHTTP)
- Use tini as PID 1 in wrenn-init.sh so zombie processes are reaped
and signals are forwarded correctly to envd
- Set standard PATH in wrenn-init.sh so child processes spawned by envd
can find common binaries (fixes "nice: ls command not found")
- Add envdclient.Init() to POST /init on envd after every boot/resume,
syncing the guest clock via unix.ClockSettime — critical after snapshot
resume where the guest clock is frozen
- Run Init in a background goroutine so it doesn't block the CreateSandbox
RPC response; a slow Init (vCPU busy with envd startup) was causing the
RPC context to be canceled before the response reached the control plane
- Update rootfs-from-container.sh and update-debug-rootfs.sh to inject
tini into the rootfs, checking the container image and host first,
downloading from GitHub releases as fallback
Replace the existing auto-destroy TTL behavior with auto-pause: when a
sandbox exceeds its timeout_sec of inactivity, the TTL reaper now pauses
it (snapshot + teardown) instead of destroying it, preserving the ability
to resume later.
Key changes:
- TTL reaper calls Pause instead of Destroy, with fallback to Destroy if
pause fails (e.g. Firecracker process already gone)
- New PingSandbox RPC resets the in-memory LastActiveAt timer
- New POST /v1/sandboxes/{id}/ping REST endpoint resets both agent memory
and DB last_active_at
- ListSandboxes RPC now includes auto_paused_sandbox_ids so the reconciler
can distinguish auto-paused sandboxes from crashed ones in a single call
- Reconciler polls every 5s (was 30s) and marks auto-paused as "paused"
vs orphaned as "stopped"
- Resume RPC accepts timeout_sec from DB so TTL survives pause/resume cycles
- Reaper checks every 2s (was 10s) and uses a detached context to avoid
incomplete pauses on app shutdown
- Default timeout_sec changed from 300 to 0 (no auto-pause unless requested)
- Add retry with backoff to dmsetupRemove for transient "device busy"
errors caused by kernel not releasing the device immediately after
Firecracker exits. Only retries on "Device or resource busy"; other
errors (not found, permission denied) return immediately.
- Thread context.Context through RemoveSnapshot/RestoreSnapshot so
retries respect cancellation. Use context.Background() in all error
cleanup paths to prevent cancelled contexts from skipping cleanup
and leaking dm devices on the host.
- Resume vCPUs on pause failure: if snapshot creation or memfile
processing fails after freezing the VM, unfreeze vCPUs so the
sandbox stays usable instead of becoming a frozen zombie.
- Fix resource leaks in Pause when CoW rename or metadata write fails:
properly clean up network, slot, loop device, and remove from boxes
map instead of leaving a dead sandbox with leaked host resources.
- Fix Resume WaitUntilReady failure: roll back CoW file to the snapshot
directory instead of deleting it, preserving the paused state so the
user can retry.
- Skip m.loops.Release when RemoveSnapshot fails during pause since
the stale dm device still references the origin loop device.
- Fix incorrect VCPUs placeholder in Resume VMConfig that used memory
size instead of a sensible default.
Pause was logging RemoveSnapshot failures as warnings and continuing,
which left stale dm devices behind. Resume then failed trying to create
a device with the same name.
- Make RemoveSnapshot failure a hard error in Pause (clean up remaining
resources and return error instead of silently proceeding)
- Add defensive stale device cleanup in RestoreSnapshot before creating
the new dm device
Use Firecracker's Diff snapshot type when re-pausing a previously
resumed sandbox, capturing only dirty pages instead of a full memory
dump. Chains up to 10 incremental generations before collapsing back
to a Full snapshot. Multi-generation diff files (memfile.{buildID})
are supported alongside the legacy single-file format in resume,
template creation, and snapshot existence checks.
Add SafeName validator (allowlist regex) to reject directory traversal
in user-supplied template and snapshot names. Validated at both API
handlers (400 response) and sandbox manager (defense in depth).
Refactor CreateNetwork with rollback slice so partially created
resources (namespace, veth, routes, iptables rules) are cleaned up
on any error. Refactor RemoveNetwork to collect and return errors
instead of silently ignoring them.
- Replace reflink rootfs copy with device-mapper snapshots (shared
read-only loop device per base template, per-sandbox sparse CoW file)
- Add devicemapper package with create/restore/remove/flatten operations
and refcounted LoopRegistry for base image loop devices
- Fix pause ordering: destroy VM before removing dm-snapshot to avoid
"device busy" error (FC must release the dm device first)
- Add test UI at GET /test for sandbox lifecycle management (create,
pause, resume, destroy, exec, snapshot create/list/delete)
- Fix DirSize to report actual disk usage (stat.Blocks * 512) instead
of apparent size, so sparse CoW files report correctly
- Add timing logs to pause flow for performance diagnostics
- Fix all lint errors across api, network, vm, uffd, and sandbox packages
- Remove obsolete internal/filesystem package (replaced by devicemapper)
- Update CLAUDE.md with device-mapper architecture documentation
Implement full snapshot lifecycle: pause (snapshot + free resources),
resume (UFFD-based lazy restore), and named snapshot templates that
can spawn new sandboxes from frozen VM state.
Key changes:
- Snapshot header system with generational diff mapping (inspired by e2b)
- UFFD server for lazy page fault handling during snapshot restore
- Stable rootfs symlink path (/tmp/fc-vm/) for snapshot compatibility
- Templates DB table and CRUD API endpoints (POST/GET/DELETE /v1/snapshots)
- CreateSnapshot/DeleteSnapshot RPCs in hostagent proto
- Reconciler excludes paused sandboxes (expected absent from host agent)
- Snapshot templates lock vcpus/memory to baked-in values
- Proper cleanup of uffd sockets and pause snapshot files on destroy
Add WebSocket-based streaming exec endpoint and streaming file
upload/download endpoints to the control plane API. Includes new
host agent RPC methods (ExecStream, StreamWriteFile, StreamReadFile),
envd client streaming support, and OpenAPI spec updates.
- REST API (chi router): sandbox CRUD, exec, pause/resume, file write/read
- PostgreSQL persistence via pgx/v5 + sqlc (sandboxes table with goose migration)
- Connect RPC client to host agent for all VM operations
- Reconciler syncs host agent state with DB every 30s (detects TTL-reaped sandboxes)
- OpenAPI 3.1 spec served at /openapi.yaml, Swagger UI at /docs
- Added WriteFile/ReadFile RPCs to hostagent proto and implementations
- File upload via multipart form, download via JSON body POST
- sandbox_id propagated from control plane to host agent on create
Implement the host agent as a Connect RPC server that orchestrates
sandbox creation, destruction, pause/resume, and command execution.
Includes sandbox manager with TTL-based reaper, network slot allocator,
rootfs cloning, hostagent proto definition with generated stubs, and
test/debug scripts. Fix Firecracker process lifetime bug where VM was
tied to HTTP request context instead of background context.
