After Firecracker snapshot restore, zombie TCP sockets from the previous
session cause Go runtime corruption inside the guest VM, making envd
unresponsive. This manifests as infinite loading in the file browser and
terminal timeouts (524) in production (HTTP/2 + Cloudflare) but not locally.
Four-part fix:
- Add ServerConnTracker to envd that tracks connections via ConnState callback,
closes idle connections and disables keep-alives before snapshot, then closes
all pre-snapshot zombie connections on restore (while preserving post-restore
connections like the /init request)
- Split envdclient into timeout (2min) and streaming (no timeout) HTTP clients;
use streaming client for file transfers and process RPCs
- Close host-side idle envdclient connections before PrepareSnapshot so FIN
packets propagate during the 3s quiesce window
- Add StreamingHTTPClient() accessor; streaming file transfer handlers in
hostagent use it instead of the timeout client
Moves 12 packages from internal/ to pkg/ (config, id, validate, events, db,
auth, lifecycle, scheduler, channels, audit, service) so they can be imported
by the enterprise repo as a Go module dependency.
Introduces pkg/cpextension (shared Extension interface + ServerContext) and
pkg/cpserver (Run() entrypoint with functional options) so the enterprise
main.go can call cpserver.Run(cpserver.WithExtensions(...)) without duplicating
the 20-step server bootstrap. Adds db/migrations/embed.go for go:embed access
to OSS SQL migrations from the enterprise module.
cmd/control-plane/main.go is reduced to a 10-line wrapper around cpserver.Run.
envd crashes with "fatal error: bad summary data" after Firecracker
snapshot/restore because the page allocator radix tree is inconsistent
when vCPUs are frozen mid-allocation. The port scanner goroutine
allocates heavily every second, making it the primary trigger.
Add POST /snapshot/prepare to envd — the host agent calls it before
vm.Pause to quiesce continuous goroutines and force GC. On restore,
PostInit restarts the port subsystem via the existing /init endpoint.
- New PortSubsystem abstraction with Start/Stop/Restart lifecycle
- Context-based goroutine cancellation (replaces irreversible channel close)
- Context-aware Signal to prevent scanner/forwarder deadlock
- Fix forwarder goroutine leak (was spinning forever on closed channel)
- Kill socat children on stop to prevent orphans across snapshots
- Fix double cmd.Wait panic (exec.Command instead of CommandContext)
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
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
- Copy envd source from e2b-dev/infra, internalize shared dependencies
into envd/internal/shared/ (keys, filesystem, id, smap, utils)
- Switch from gRPC to Connect RPC for all envd services
- Update module paths to git.omukk.dev/wrenn/{sandbox,sandbox/envd}
- Add proto specs (process, filesystem) with buf-based code generation
- Implement full envd: process exec, filesystem ops, port forwarding,
cgroup management, MMDS integration, and HTTP API
- Update main module dependencies (firecracker SDK, pgx, goose, etc.)
- Remove placeholder .gitkeep files replaced by real implementations
