firecracker

Documentation

Index

• func DevPath(idx int) string
• func EnsureVmlinux(kernelPath string) (string, error)
• func IsRelayMode() bool
• func RunRelay(ctx context.Context)
• type Config
  • func NewConfig(conf *config.Config) *Config
  • func (c *Config) BinaryName() string
  • func (c *Config) COWRawPath(vmID string) string
  • func (c *Config) PIDFileName() string
• type Firecracker
  • func New(conf *config.Config) (*Firecracker, error)
  • func (fc *Firecracker) Clone(ctx context.Context, vmID string, vmCfg *types.VMConfig, ...) (*types.VM, error)
  • func (fc *Firecracker) Console(ctx context.Context, ref string) (io.ReadWriteCloser, error)
  • func (fc *Firecracker) Create(ctx context.Context, id string, vmCfg *types.VMConfig, ...) (*types.VM, error)
  • func (fc *Firecracker) Delete(ctx context.Context, refs []string, force bool) ([]string, error)
  • func (fc *Firecracker) DirectClone(ctx context.Context, vmID string, vmCfg *types.VMConfig, ...) (*types.VM, error)
  • func (fc *Firecracker) DirectRestore(ctx context.Context, vmRef string, vmCfg *types.VMConfig, srcDir string) (*types.VM, error)
  • func (fc *Firecracker) Restore(ctx context.Context, vmRef string, vmCfg *types.VMConfig, snapshot io.Reader) (*types.VM, error)
  • func (fc *Firecracker) Snapshot(ctx context.Context, ref string) (*types.SnapshotConfig, io.ReadCloser, error)
  • func (fc *Firecracker) Start(ctx context.Context, refs []string) ([]string, error)
  • func (fc *Firecracker) Stop(ctx context.Context, refs []string) ([]string, error)

Functions

func DevPath

func DevPath(idx int) string

DevPath maps idx to vda..vdz, vdaa..vdaz, vdba..vdbz, ...

func EnsureVmlinux

func EnsureVmlinux(kernelPath string) (string, error)

EnsureVmlinux decompresses kernelPath if needed and returns the ELF path.

func IsRelayMode

func IsRelayMode() bool

IsRelayMode returns true when the process was started as a console relay.

func RunRelay

func RunRelay(ctx context.Context)

RunRelay runs the console relay loop. Called from main.go when IsRelayMode() returns true. The relay process inherits:

• fd 3: PTY master (bidirectional serial I/O with FC)
• fd 4: Unix listener file (console.sock)
• _COCOON_FC_PID: Firecracker PID to monitor

A single persistent goroutine reads from the PTY master for the lifetime of the relay. Each console session receives output via a broadcast mechanism — no per-session goroutine reads the PTY, so disconnecting a session never leaves stale readers competing for data.

Types

type Config

type Config struct {
	hypervisor.BaseConfig
}

Config holds Firecracker specific configuration.

func NewConfig

func NewConfig(conf *config.Config) *Config

NewConfig creates a Config from a global config.

func (*Config) BinaryName

func (c *Config) BinaryName() string

func (*Config) COWRawPath

func (c *Config) COWRawPath(vmID string) string

func (*Config) PIDFileName

func (c *Config) PIDFileName() string

type Firecracker

type Firecracker struct {
	*hypervisor.Backend
	// contains filtered or unexported fields
}

Firecracker implements hypervisor.Hypervisor using the Firecracker VMM. Only OCI images (direct kernel boot) are supported — no UEFI, no cloudimg, no Windows.

func New

func New(conf *config.Config) (*Firecracker, error)

New creates a Firecracker backend.

func (*Firecracker) Clone

func (fc *Firecracker) Clone(ctx context.Context, vmID string, vmCfg *types.VMConfig, networkConfigs []*types.NetworkConfig, snapshotConfig *types.SnapshotConfig, snapshot io.Reader) (*types.VM, error)

func (*Firecracker) Console

func (fc *Firecracker) Console(ctx context.Context, ref string) (io.ReadWriteCloser, error)

func (*Firecracker) Create

func (fc *Firecracker) Create(ctx context.Context, id string, vmCfg *types.VMConfig, storageConfigs []*types.StorageConfig, networkConfigs []*types.NetworkConfig, bootCfg *types.BootConfig) (*types.VM, error)

func (*Firecracker) Delete

func (fc *Firecracker) Delete(ctx context.Context, refs []string, force bool) ([]string, error)

Delete removes VMs. Running VMs require force=true (stops them first).

func (*Firecracker) DirectClone

func (fc *Firecracker) DirectClone(ctx context.Context, vmID string, vmCfg *types.VMConfig, networkConfigs []*types.NetworkConfig, snapshotConfig *types.SnapshotConfig, srcDir string) (*types.VM, error)

DirectClone clones from a local snapshot dir. Per-type: hardlink mem, reflink/copy COW, plain copy metadata.

func (*Firecracker) DirectRestore

func (fc *Firecracker) DirectRestore(ctx context.Context, vmRef string, vmCfg *types.VMConfig, srcDir string) (*types.VM, error)

func (*Firecracker) Restore

func (fc *Firecracker) Restore(ctx context.Context, vmRef string, vmCfg *types.VMConfig, snapshot io.Reader) (*types.VM, error)

func (*Firecracker) Snapshot

func (fc *Firecracker) Snapshot(ctx context.Context, ref string) (*types.SnapshotConfig, io.ReadCloser, error)

Snapshot pauses, captures vmstate+mem+COW, resumes, and streams the result.

func (*Firecracker) Start

func (fc *Firecracker) Start(ctx context.Context, refs []string) ([]string, error)

Start launches FC, configures via REST, then InstanceStart.

func (*Firecracker) Stop

func (fc *Firecracker) Stop(ctx context.Context, refs []string) ([]string, error)

Stop shuts down the Firecracker process for each VM ref. Honors --force (skip SendCtrlAltDel, immediate kill) and --timeout (wait for guest to respond to SendCtrlAltDel before escalating).