Firecracker 1.15.1-patch-v2

Firecracker 1.15.1-patch-v2

This release replaces the historical pre-fault patch-v2 build with the nested-KVM runtime. Both runtime archives are built from 95c9c9653ae3ed1517a312fd39a22bedc6586e01, and the release tag points to that source commit.

• Read legacy v9 snapshots on x86_64 and aarch64; write new snapshots as v1000.
• Preserve x86_64 nested-KVM state, including IA32_XSS and AMD SVM header-only GIF state.
• Each runtime archive contains firecracker and cpu-template-helper. The aarch64 programs are compiled natively on ARM64; x86_64 programs are compiled on x86_64.
• vmlinux-6.18-x86_64 is the previously tested uncompressed x86_64 ELF guest kernel with built-in KVM.
• vmlinux-6.18-aarch64 is the tested uncompressed ARM64 Image for ordinary KVM guests. Its guest kernel release is 6.18.0.

Public-download validation

On both an Intel x86_64 host and a native ARM64 host, AgentENV started with an empty dependency directory and no Firecracker or kernel overrides. Automatic public downloads, Ubuntu 24.04 cold start, and pause/resume passed. Disk and memory markers survived restore, and the running Firecracker executable matched the published build. Guest kernel releases were 6.18.0-agentenv-nestedvirt on x86_64 and 6.18.0 on aarch64.

Updating an existing installation

The old pre-fault patch-v2 assets have been archived before replacement. If that version is already cached, stop AgentENV and replace its cached patch-v2 runtime and helper before restarting; an existing non-empty dependency file is not automatically downloaded again. Fresh dependency directories retrieve the replacement assets.

Restoring an old snapshot retains its captured guest kernel. Selecting Linux 6.18 changes cold starts and newly built templates, not the kernel already present in a snapshot. Old Firecracker runtimes cannot read newly written v1000 snapshots.

The separate nestedvirt-v1 release remains available for installations and upstream PRs that still reference it.