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Firecracker

INFRA · APIS
Velocity5.0

Secure and fast microVM manager for serverless workloads

firecracker-microvm.github.io ↗

Firecracker adds PCI device hotplugging and virtio reset — microVM lifecycle management takes a meaningful step.

virtualizationcloud-infrastructureopen-sourceserverlessmicrovm
◆Current state
Firecracker is Amazon's open-source microVM hypervisor, used as the isolation layer for Lambda and Fargate. Recent releases have been focused on expanding the microVM lifecycle model: v1.16.0 added developer preview PCI virtio device hotplug (block, pmem, net), v1.17.0 adds virtio device reset support and richer metrics emission (instance ID and operator-defined properties). The release cadence has accelerated — multiple patch releases within the same minor version cycle.
◆Where it's heading
The hotplugging work in v1.16.0 is the most architecturally significant change in this window: being able to attach and detach storage and network devices from a running microVM without restarting it opens up dynamic workload scenarios that previously required a full cold start. The v1.17.0 metrics additions (instance ID emission, operator-defined key-value pairs) suggest growing operational observability requirements from fleet operators running Firecracker at scale.
◆Prediction
The PCI hotplug is still developer preview — GA is the likely near-term milestone. Automatic guest notification for hotplug events (currently requiring manual PCI bus rescan) is the obvious follow-on feature. The metrics expansion suggests more structured telemetry is coming to support fleet-level observability tooling.

◆Recent moves

  1. 12d ago

    Firecracker v1.17.0: virtio device reset, richer metrics, 20% memory reduction

    v1.17.0 adds virtio device reset support and two opt-in metrics fields — instance ID emission and operator-defined key-value pairs on PUT /metrics. Both are observability enhancements for fleet operators managing many microVMs. The 20% storage memory reduction and 35% parsing time reduction noted in this entry are substantial operational gains.

    View source ↗
  2. 12d ago

    Firecracker v1.16.2

    v1.16.2 is a targeted fix for a CPU cache topology regression on host kernels in the 6.3–6.10 range and a snapshot format version bump — both breaking for users on affected kernel ranges or holding cross-version snapshots, but not user-visible capability changes.

    View source ↗
  3. 2mo ago

    Firecracker v1.16.1

    v1.16.1 reverts a symlink restriction that broke jailer workflows and fixes a vsock TX queue timeout regression after snapshot restore — targeted fixes for specific operational failure modes introduced in v1.16.0.

    View source ↗
  4. 3mo ago

    Firecracker v1.16.0

    ⚡ SPARK

    PCI virtio device hotplugging in developer preview is the most significant microVM lifecycle capability in Firecracker's recent history — the ability to attach and detach block, pmem, and network devices from a running microVM without a cold restart opens dynamic workload configurations that previously required full reinitialization.

    View source ↗
  5. 5mo ago

    Firecracker v1.14.4

    v1.14.4 is a backport patch release — specific fixes applied to the stable 1.14.x line for users not yet on 1.15 or 1.16, typically addressing critical or security-relevant issues without the newer minor's changes.

    View source ↗
  6. 5mo ago

    Firecracker v1.15.1

    v1.15.1 is a patch release on the 1.15.x stable line — targeted fixes for the 1.15 feature set without the larger changes in 1.16.

    View source ↗