Add experimental Void guest workflow and vsock agent

Make iterating on a Firecracker-friendly Void guest practical without replacing the Debian default image path.

Add local Void rootfs build/register/verify plumbing, a language-agnostic dev package baseline, and guest SSH/work-disk hardening so new images use the runtime bundle key, keep a normal root bash environment, and repair stale nested /root layouts on restart.

Replace the guest PING/PONG responder with an HTTP /healthz agent over vsock, rename the runtime bundle and config surface from ping helper to agent while still accepting the legacy keys, and route the post-SSH reminder through the new vm.health path.

Validated with GOCACHE=/tmp/banger-gocache go test ./..., make build, bash -n customize.sh make-rootfs-void.sh, and git diff --check.
This commit is contained in:
Thales Maciel 2026-03-19 14:51:25 -03:00
parent c8d9a122f9
commit 3ed78fdcfc
No known key found for this signature in database
GPG key ID: 33112E6833C34679
42 changed files with 2222 additions and 388 deletions

View file

@ -34,7 +34,8 @@ type BundleMetadata struct {
SSHKeyPath string `json:"ssh_key_path" toml:"ssh_key_path"`
NamegenPath string `json:"namegen_path" toml:"namegen_path"`
CustomizeScript string `json:"customize_script" toml:"customize_script"`
VSockPingHelperPath string `json:"vsock_ping_helper_path" toml:"vsock_ping_helper_path"`
VSockAgentPath string `json:"vsock_agent_path,omitempty" toml:"vsock_agent_path"`
VSockPingHelperPath string `json:"vsock_ping_helper_path,omitempty" toml:"vsock_ping_helper_path"`
DefaultPackages string `json:"default_packages_file" toml:"default_packages_file"`
DefaultRootfs string `json:"default_rootfs" toml:"default_rootfs"`
DefaultBaseRootfs string `json:"default_base_rootfs,omitempty" toml:"default_base_rootfs"`
@ -211,7 +212,7 @@ func validateBundleMetadata(runtimeDir string, meta BundleMetadata) error {
{meta.SSHKeyPath, "ssh_key_path"},
{meta.NamegenPath, "namegen_path"},
{meta.CustomizeScript, "customize_script"},
{meta.VSockPingHelperPath, "vsock_ping_helper_path"},
{meta.VSockAgentPath, "vsock_agent_path"},
{meta.DefaultPackages, "default_packages_file"},
{meta.DefaultRootfs, "default_rootfs"},
{meta.DefaultKernel, "default_kernel"},
@ -230,7 +231,7 @@ func validateBundleMetadata(runtimeDir string, meta BundleMetadata) error {
{meta.SSHKeyPath, "ssh_key_path", true},
{meta.NamegenPath, "namegen_path", true},
{meta.CustomizeScript, "customize_script", true},
{meta.VSockPingHelperPath, "vsock_ping_helper_path", true},
{meta.VSockAgentPath, "vsock_agent_path", true},
{meta.DefaultPackages, "default_packages_file", true},
{meta.DefaultRootfs, "default_rootfs", true},
{meta.DefaultBaseRootfs, "default_base_rootfs", false},
@ -269,7 +270,7 @@ func metadataArchiveBytes(runtimeDir string, meta BundleMetadata) ([]byte, error
strings.TrimSpace(meta.SSHKeyPath) == "" &&
strings.TrimSpace(meta.NamegenPath) == "" &&
strings.TrimSpace(meta.CustomizeScript) == "" &&
strings.TrimSpace(meta.VSockPingHelperPath) == "" &&
strings.TrimSpace(meta.VSockAgentPath) == "" &&
strings.TrimSpace(meta.DefaultPackages) == "" &&
strings.TrimSpace(meta.DefaultRootfs) == "" &&
strings.TrimSpace(meta.DefaultBaseRootfs) == "" &&
@ -290,7 +291,11 @@ func normalizeBundleMetadata(meta BundleMetadata) BundleMetadata {
meta.SSHKeyPath = strings.TrimSpace(meta.SSHKeyPath)
meta.NamegenPath = strings.TrimSpace(meta.NamegenPath)
meta.CustomizeScript = strings.TrimSpace(meta.CustomizeScript)
meta.VSockAgentPath = strings.TrimSpace(meta.VSockAgentPath)
meta.VSockPingHelperPath = strings.TrimSpace(meta.VSockPingHelperPath)
if meta.VSockAgentPath == "" {
meta.VSockAgentPath = meta.VSockPingHelperPath
}
meta.DefaultPackages = strings.TrimSpace(meta.DefaultPackages)
meta.DefaultRootfs = strings.TrimSpace(meta.DefaultRootfs)
meta.DefaultBaseRootfs = strings.TrimSpace(meta.DefaultBaseRootfs)

View file

@ -20,7 +20,7 @@ func TestBootstrapExtractsBundleAndValidatesChecksum(t *testing.T) {
"runtime/firecracker": "fc",
"runtime/id_ed25519": "key",
"runtime/namegen": "namegen",
"runtime/banger-vsock-pingd": "pingd",
"runtime/banger-vsock-agent": "agent",
"runtime/customize.sh": "#!/bin/bash\n",
"runtime/packages.sh": "#!/bin/bash\n",
"runtime/packages.apt": "vim\n",
@ -28,7 +28,7 @@ func TestBootstrapExtractsBundleAndValidatesChecksum(t *testing.T) {
"runtime/wtf/root/boot/vmlinux-6.8.0-94-generic": "kernel",
"runtime/wtf/root/boot/initrd.img-6.8.0-94-generic": "initrd",
"runtime/wtf/root/lib/modules/6.8.0-94-generic/modules.dep": "dep",
"runtime/bundle.json": mustJSON(t, BundleMetadata{FirecrackerBin: "firecracker", SSHKeyPath: "id_ed25519", NamegenPath: "namegen", CustomizeScript: "customize.sh", VSockPingHelperPath: "banger-vsock-pingd", DefaultPackages: "packages.apt", DefaultRootfs: "rootfs-docker.ext4", DefaultKernel: "wtf/root/boot/vmlinux-6.8.0-94-generic", DefaultInitrd: "wtf/root/boot/initrd.img-6.8.0-94-generic", DefaultModulesDir: "wtf/root/lib/modules/6.8.0-94-generic"}),
"runtime/bundle.json": mustJSON(t, BundleMetadata{FirecrackerBin: "firecracker", SSHKeyPath: "id_ed25519", NamegenPath: "namegen", CustomizeScript: "customize.sh", VSockAgentPath: "banger-vsock-agent", DefaultPackages: "packages.apt", DefaultRootfs: "rootfs-docker.ext4", DefaultKernel: "wtf/root/boot/vmlinux-6.8.0-94-generic", DefaultInitrd: "wtf/root/boot/initrd.img-6.8.0-94-generic", DefaultModulesDir: "wtf/root/lib/modules/6.8.0-94-generic"}),
})
archivePath := filepath.Join(manifestDir, "bundle.tar.gz")
if err := os.WriteFile(archivePath, bundleData, 0o644); err != nil {
@ -39,7 +39,7 @@ func TestBootstrapExtractsBundleAndValidatesChecksum(t *testing.T) {
URL: "./bundle.tar.gz",
SHA256: sha256Hex(bundleData),
BundleRoot: "runtime",
RequiredPaths: []string{"firecracker", "banger-vsock-pingd", "customize.sh", "packages.apt", "rootfs-docker.ext4", "wtf/root/boot/vmlinux-6.8.0-94-generic", "wtf/root/lib/modules/6.8.0-94-generic"},
RequiredPaths: []string{"firecracker", "banger-vsock-agent", "customize.sh", "packages.apt", "rootfs-docker.ext4", "wtf/root/boot/vmlinux-6.8.0-94-generic", "wtf/root/lib/modules/6.8.0-94-generic"},
}
outDir := filepath.Join(t.TempDir(), "runtime")
if err := Bootstrap(context.Background(), manifest, filepath.Join(manifestDir, "runtime-bundle.toml"), outDir); err != nil {
@ -100,7 +100,7 @@ func TestPackageWritesArchive(t *testing.T) {
"firecracker",
"id_ed25519",
"namegen",
"banger-vsock-pingd",
"banger-vsock-agent",
"customize.sh",
"packages.apt",
"rootfs-docker.ext4",
@ -128,22 +128,22 @@ func TestPackageWritesArchive(t *testing.T) {
manifest := Manifest{
BundleRoot: "runtime",
BundleMeta: BundleMetadata{
FirecrackerBin: "firecracker",
SSHKeyPath: "id_ed25519",
NamegenPath: "namegen",
CustomizeScript: "customize.sh",
VSockPingHelperPath: "banger-vsock-pingd",
DefaultPackages: "packages.apt",
DefaultRootfs: "rootfs-docker.ext4",
DefaultKernel: "wtf/root/boot/vmlinux-6.8.0-94-generic",
DefaultInitrd: "wtf/root/boot/initrd.img-6.8.0-94-generic",
DefaultModulesDir: "wtf/root/lib/modules/6.8.0-94-generic",
FirecrackerBin: "firecracker",
SSHKeyPath: "id_ed25519",
NamegenPath: "namegen",
CustomizeScript: "customize.sh",
VSockAgentPath: "banger-vsock-agent",
DefaultPackages: "packages.apt",
DefaultRootfs: "rootfs-docker.ext4",
DefaultKernel: "wtf/root/boot/vmlinux-6.8.0-94-generic",
DefaultInitrd: "wtf/root/boot/initrd.img-6.8.0-94-generic",
DefaultModulesDir: "wtf/root/lib/modules/6.8.0-94-generic",
},
RequiredPaths: []string{
"firecracker",
"id_ed25519",
"namegen",
"banger-vsock-pingd",
"banger-vsock-agent",
"customize.sh",
"packages.apt",
"rootfs-docker.ext4",
@ -186,7 +186,36 @@ func TestPackageWritesArchive(t *testing.T) {
func TestLoadBundleMetadataRejectsMissingRequiredPath(t *testing.T) {
runtimeDir := t.TempDir()
for _, rel := range []string{"firecracker", "id_ed25519", "namegen", "banger-vsock-pingd", "customize.sh", "packages.apt", "rootfs-docker.ext4"} {
for _, rel := range []string{"firecracker", "id_ed25519", "namegen", "banger-vsock-agent", "customize.sh", "packages.apt", "rootfs-docker.ext4"} {
path := filepath.Join(runtimeDir, rel)
if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
t.Fatalf("MkdirAll: %v", err)
}
if err := os.WriteFile(path, []byte(rel), 0o644); err != nil {
t.Fatalf("WriteFile: %v", err)
}
}
data := mustJSON(t, BundleMetadata{
FirecrackerBin: "firecracker",
SSHKeyPath: "id_ed25519",
NamegenPath: "namegen",
CustomizeScript: "customize.sh",
VSockAgentPath: "banger-vsock-agent",
DefaultPackages: "packages.apt",
DefaultRootfs: "rootfs-docker.ext4",
DefaultKernel: "missing-kernel",
})
if err := os.WriteFile(filepath.Join(runtimeDir, BundleMetadataFile), []byte(data), 0o644); err != nil {
t.Fatalf("WriteFile: %v", err)
}
if _, err := LoadBundleMetadata(runtimeDir); err == nil || !strings.Contains(err.Error(), "default_kernel") {
t.Fatalf("LoadBundleMetadata() error = %v, want default_kernel failure", err)
}
}
func TestLoadBundleMetadataAcceptsLegacyVsockPingHelperPath(t *testing.T) {
runtimeDir := t.TempDir()
for _, rel := range []string{"firecracker", "id_ed25519", "namegen", "banger-vsock-pingd", "customize.sh", "packages.apt", "rootfs-docker.ext4", "wtf/root/boot/vmlinux-6.8.0-94-generic"} {
path := filepath.Join(runtimeDir, rel)
if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
t.Fatalf("MkdirAll: %v", err)
@ -203,13 +232,17 @@ func TestLoadBundleMetadataRejectsMissingRequiredPath(t *testing.T) {
VSockPingHelperPath: "banger-vsock-pingd",
DefaultPackages: "packages.apt",
DefaultRootfs: "rootfs-docker.ext4",
DefaultKernel: "missing-kernel",
DefaultKernel: "wtf/root/boot/vmlinux-6.8.0-94-generic",
})
if err := os.WriteFile(filepath.Join(runtimeDir, BundleMetadataFile), []byte(data), 0o644); err != nil {
t.Fatalf("WriteFile: %v", err)
}
if _, err := LoadBundleMetadata(runtimeDir); err == nil || !strings.Contains(err.Error(), "default_kernel") {
t.Fatalf("LoadBundleMetadata() error = %v, want default_kernel failure", err)
meta, err := LoadBundleMetadata(runtimeDir)
if err != nil {
t.Fatalf("LoadBundleMetadata: %v", err)
}
if meta.VSockAgentPath != "banger-vsock-pingd" {
t.Fatalf("VSockAgentPath = %q", meta.VSockAgentPath)
}
}