Documentation
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Overview ¶
Package firecracker implements the hypervisor interfaces with Firecracker. It embeds the supported VMM binaries and drives them over their API socket using the hand-written types in api.go. Unsupported operations return errors.ErrUnsupported, as Capabilities reports.
Index ¶
- func Extract(dstPath string, version Version) (string, error)
- type Hypervisor
- func (h *Hypervisor) DestroyVM(context.Context) error
- func (h *Hypervisor) PauseVM(ctx context.Context) error
- func (h *Hypervisor) ResizeVMCPU(context.Context, int) error
- func (h *Hypervisor) ResizeVMMemory(ctx context.Context, bytes int64) error
- func (h *Hypervisor) ResumeVM(ctx context.Context) error
- func (h *Hypervisor) Shutdown(ctx context.Context) error
- func (h *Hypervisor) ShutdownVM(ctx context.Context) error
- func (h *Hypervisor) SnapshotVM(ctx context.Context, destPath string) error
- func (h *Hypervisor) VMInfo(ctx context.Context) (*hypervisor.VMInfo, error)
- type Starter
- func (s *Starter) Capabilities() hypervisor.Capabilities
- func (s *Starter) Connect(socketPath string) (hypervisor.Hypervisor, error)
- func (s *Starter) DefaultKernelArgs() string
- func (s *Starter) PowerOffEndsVM() bool
- func (s *Starter) RestoreVM(ctx context.Context, socketPath string, snapshotPath string, ...) (*process.Process, hypervisor.Hypervisor, error)
- func (s *Starter) StartVM(ctx context.Context, socketPath string, spec hypervisor.VMSpec) (*process.Process, hypervisor.Hypervisor, error)
- func (s *Starter) Version() string
- type Version
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Hypervisor ¶
type Hypervisor struct {
// contains filtered or unexported fields
}
Hypervisor controls one Firecracker VMM over its API socket.
func NewHypervisor ¶
func NewHypervisor(socketPath string) *Hypervisor
NewHypervisor returns a Hypervisor for the VMM serving its API on socketPath. It does not connect until the first request.
func (*Hypervisor) DestroyVM ¶
func (h *Hypervisor) DestroyVM(context.Context) error
DestroyVM is unsupported: Firecracker has no way to discard a guest short of ending the VMM process.
func (*Hypervisor) PauseVM ¶
func (h *Hypervisor) PauseVM(ctx context.Context) error
PauseVM halts the guest's vCPUs.
func (*Hypervisor) ResizeVMCPU ¶
func (h *Hypervisor) ResizeVMCPU(context.Context, int) error
ResizeVMCPU is unsupported: Firecracker cannot hotplug vCPUs.
func (*Hypervisor) ResizeVMMemory ¶
func (h *Hypervisor) ResizeVMMemory(ctx context.Context, bytes int64) error
ResizeVMMemory sets the guest's total memory to bytes by plugging or unplugging virtio-mem memory, and waits until the guest has, or ctx is done.
func (*Hypervisor) ResumeVM ¶
func (h *Hypervisor) ResumeVM(ctx context.Context) error
ResumeVM continues a paused guest.
func (*Hypervisor) Shutdown ¶
func (h *Hypervisor) Shutdown(ctx context.Context) error
Shutdown stops the VMM. Firecracker has no request that ends the process directly; it exits when the guest resets, which ShutdownVM brings about. Where that is unsupported, the caller has to end the process itself.
func (*Hypervisor) ShutdownVM ¶
func (h *Hypervisor) ShutdownVM(ctx context.Context) error
ShutdownVM asks the guest to shut down by sending it Ctrl+Alt+Del, which Linux treats as a request to reboot. Firecracker exits when the guest resets, so this also ends the VMM. It is available on x86 only.
func (*Hypervisor) SnapshotVM ¶
func (h *Hypervisor) SnapshotVM(ctx context.Context, destPath string) error
SnapshotVM writes a full snapshot of a paused guest into the directory destPath: its device state and its memory, as the files RestoreVM reads.
func (*Hypervisor) VMInfo ¶ added in v0.4.0
func (h *Hypervisor) VMInfo(ctx context.Context) (*hypervisor.VMInfo, error)
VMInfo reports the guest's state, and its memory including any hotplugged.
type Starter ¶
type Starter struct {
// contains filtered or unexported fields
}
Starter implements hypervisor.Starter for Firecracker.
func NewStarter ¶
NewStarter creates a Starter for a Firecracker binary. It invokes the binary once to parse and validate its version.
func (*Starter) Capabilities ¶ added in v0.4.0
func (s *Starter) Capabilities() hypervisor.Capabilities
Capabilities reports what Firecracker supports.
func (*Starter) Connect ¶
func (s *Starter) Connect(socketPath string) (hypervisor.Hypervisor, error)
Connect returns a client for an already-running Firecracker VMM.
func (*Starter) DefaultKernelArgs ¶ added in v0.4.0
DefaultKernelArgs returns the kernel command line Firecracker guests need: output on the serial console, no PCI bus, a reset on panic so that a wedged guest ends its VMM rather than lingering, and memory that a resize can take back.
func (*Starter) PowerOffEndsVM ¶
PowerOffEndsVM is false: Firecracker has no ACPI power button, so a guest that powers off only halts. It exits when the guest resets.
func (*Starter) RestoreVM ¶
func (s *Starter) RestoreVM( ctx context.Context, socketPath string, snapshotPath string, spec hypervisor.RestoreSpec, ) (*process.Process, hypervisor.Hypervisor, error)
RestoreVM launches Firecracker and restores a guest from a snapshot written by SnapshotVM. The guest is left paused; call ResumeVM.
Its memory is restored on demand. Firecracker maps the snapshot's memory file into the guest privately, so the kernel restores each page when the guest first uses it.
func (*Starter) StartVM ¶
func (s *Starter) StartVM( ctx context.Context, socketPath string, spec hypervisor.VMSpec, ) (*process.Process, hypervisor.Hypervisor, error)
StartVM launches Firecracker, configures the guest and boots it. It returns the VMM process and a client for controlling it.
type Version ¶
type Version string
Version identifies a supported Firecracker release.
const DefaultVersion Version = "v1.17.0"
DefaultVersion is the version used when no explicit version is requested.
func SupportedVersions ¶
func SupportedVersions() []Version
SupportedVersions returns the versions whose binaries are embedded.
Source Files