rundmc

README

RunDMC - Diminuatively Managed RunC Containers

RunDMC is a small wrapper around runC.

High Level Architecture

Each container is stored as a subdirectory of a directory called 'the depot'. The depot is the source of truth for RunDMC, when a container is created, this amounts to creating an Open Container Spec compliant container as a subdirectory of the depot directory. The subdirectory is named after the container's handle. Looking up a container amounts to checking for the presence of a subdirectory with the right name.

To execute processes in a container, we launch the runc binary inside the container directory and pass it a custom process spec. Since we want to control the container lifecycle via the API without the restriction that the container dies when its first process dies, the containers are always created with a no-op initial process that never exits. User processes are all executed using runc exec.

The process_tracker allows reattaching to running containers when RunDMC is restarted. It holds on to process input/output streams and allows reconnecting to them later.

Documentation

Index

• func IsMountPoint(path string) (bool, error)
• func NewEventStore(props Properties) *events
• func NewStateStore(props Properties) *states
• type BundleGenerator
• type BundleTemplate
  • func (b BundleTemplate) Generate(spec spec.DesiredContainerSpec) (goci.Bndl, error)
• type BundlerRule
• type CPUCgrouper
• type Containerizer
  • func New(depot Depot, bundler BundleGenerator, runtime OCIRuntime, ...) *Containerizer
  • func (c *Containerizer) Attach(log lager.Logger, handle string, processID string, io garden.ProcessIO) (garden.Process, error)
  • func (c *Containerizer) Create(log lager.Logger, spec spec.DesiredContainerSpec) error
  • func (c *Containerizer) Destroy(log lager.Logger, handle string) error
  • func (c *Containerizer) Handles() ([]string, error)
  • func (c *Containerizer) Info(log lager.Logger, handle string) (spec.ActualContainerSpec, error)
  • func (c *Containerizer) Metrics(log lager.Logger, handle string) (gardener.ActualContainerMetrics, error)
  • func (c *Containerizer) RemoveBundle(log lager.Logger, handle string) error
  • func (c *Containerizer) Run(log lager.Logger, handle string, spec garden.ProcessSpec, io garden.ProcessIO) (garden.Process, error)
  • func (c *Containerizer) Shutdown() error
  • func (c *Containerizer) Stop(log lager.Logger, handle string, kill bool) error
  • func (c *Containerizer) StreamIn(log lager.Logger, handle string, spec garden.StreamInSpec) error
  • func (c *Containerizer) StreamOut(log lager.Logger, handle string, spec garden.StreamOutSpec) (io.ReadCloser, error)
  • func (c *Containerizer) WatchRuntimeEvents(log lager.Logger) error
• type Depot
• type EventStore
• type MountOptionsGetter
• type MountPointChecker
  • func (c MountPointChecker) IsMountPoint(path string) (bool, error)
• type NstarRunner
  • func NewNstarRunner(nstarPath, tarPath string, runner commandrunner.CommandRunner) NstarRunner
• type OCIRuntime
• type PeaCreator
• type PeaUsernameResolver
• type ProcessesStopper
• type Properties
• type RuntimeStopper
• type State
• type StateStore
• type Status

Functions

func IsMountPoint

func IsMountPoint(path string) (bool, error)

func NewEventStore

func NewEventStore(props Properties) *events

func NewStateStore

func NewStateStore(props Properties) *states

Types

type BundleGenerator

type BundleGenerator interface {
	Generate(desiredContainerSpec spec.DesiredContainerSpec) (goci.Bndl, error)
}

type BundleTemplate

type BundleTemplate struct {
	Rules []BundlerRule
}

func (BundleTemplate) Generate

func (b BundleTemplate) Generate(spec spec.DesiredContainerSpec) (goci.Bndl, error)

type BundlerRule

type BundlerRule interface {
	Apply(bndle goci.Bndl, desiredContainerSpec spec.DesiredContainerSpec) (goci.Bndl, error)
}

type CPUCgrouper

type CPUCgrouper interface {
	CreateBadCgroup(handle string) error
	DestroyBadCgroup(handle string) error
	ReadBadCgroupUsage(handle string) (garden.ContainerCPUStat, error)
}

type Containerizer

type Containerizer struct {
	// contains filtered or unexported fields
}

Containerizer knows how to manage a depot of container bundles

func New

func New(
	depot Depot,
	bundler BundleGenerator,
	runtime OCIRuntime,
	nstarRunner NstarRunner,
	processesStopper ProcessesStopper,
	events EventStore,
	states StateStore,
	peaCreator PeaCreator,
	peaUsernameResolver PeaUsernameResolver,
	cpuEntitlementPerShare float64,
	runtimeStopper RuntimeStopper,
	cpuCgrouper CPUCgrouper,
) *Containerizer

func (*Containerizer) Attach

func (c *Containerizer) Attach(log lager.Logger, handle string, processID string, io garden.ProcessIO) (garden.Process, error)

func (*Containerizer) Create

func (c *Containerizer) Create(log lager.Logger, spec spec.DesiredContainerSpec) error

Create creates a bundle in the depot and starts its init process

func (*Containerizer) Destroy

func (c *Containerizer) Destroy(log lager.Logger, handle string) error

Destroy deletes the container and the bundle directory

func (*Containerizer) Handles

func (c *Containerizer) Handles() ([]string, error)

func (*Containerizer) Info

func (c *Containerizer) Info(log lager.Logger, handle string) (spec.ActualContainerSpec, error)

func (*Containerizer) Metrics

func (c *Containerizer) Metrics(log lager.Logger, handle string) (gardener.ActualContainerMetrics, error)

func (*Containerizer) RemoveBundle

func (c *Containerizer) RemoveBundle(log lager.Logger, handle string) error

func (*Containerizer) Run

func (c *Containerizer) Run(log lager.Logger, handle string, spec garden.ProcessSpec, io garden.ProcessIO) (garden.Process, error)

Run runs a process inside a running container

func (*Containerizer) Shutdown

func (c *Containerizer) Shutdown() error

func (*Containerizer) Stop

func (c *Containerizer) Stop(log lager.Logger, handle string, kill bool) error

Stop stops all the processes other than the init process in the container

func (*Containerizer) StreamIn

func (c *Containerizer) StreamIn(log lager.Logger, handle string, spec garden.StreamInSpec) error

StreamIn streams files in to the container

func (*Containerizer) StreamOut

func (c *Containerizer) StreamOut(log lager.Logger, handle string, spec garden.StreamOutSpec) (io.ReadCloser, error)

StreamOut stream files from the container

func (*Containerizer) WatchRuntimeEvents

func (c *Containerizer) WatchRuntimeEvents(log lager.Logger) error

type Depot

type Depot interface {
	Destroy(log lager.Logger, handle string) error
}

type EventStore

type EventStore interface {
	OnEvent(id string, event string) error
	Events(id string) []string
}

type MountOptionsGetter

type MountOptionsGetter func(path string) ([]string, error)

type MountPointChecker

type MountPointChecker func(path string) (bool, error)

func (MountPointChecker) IsMountPoint

func (c MountPointChecker) IsMountPoint(path string) (bool, error)

type NstarRunner

type NstarRunner interface {
	StreamIn(log lager.Logger, pid int, path string, user string, tarStream io.Reader) error
	StreamOut(log lager.Logger, pid int, path string, user string) (io.ReadCloser, error)
}

func NewNstarRunner

func NewNstarRunner(nstarPath, tarPath string, runner commandrunner.CommandRunner) NstarRunner

type OCIRuntime

type OCIRuntime interface {
	Create(log lager.Logger, id string, bundle goci.Bndl, io garden.ProcessIO) error
	Exec(log lager.Logger, id string, spec garden.ProcessSpec, io garden.ProcessIO) (garden.Process, error)
	Attach(log lager.Logger, id, processId string, io garden.ProcessIO) (garden.Process, error)
	Delete(log lager.Logger, id string) error
	State(log lager.Logger, id string) (State, error)
	Stats(log lager.Logger, id string) (gardener.StatsContainerMetrics, error)
	Events(log lager.Logger) (<-chan event.Event, error)
	ContainerHandles() ([]string, error)
	ContainerPeaHandles(log lager.Logger, id string) ([]string, error)
	BundleInfo(log lager.Logger, id string) (string, goci.Bndl, error)
	RemoveBundle(log lager.Logger, id string) error
}

type PeaCreator

type PeaCreator interface {
	CreatePea(log lager.Logger, processSpec garden.ProcessSpec, pio garden.ProcessIO, sandboxHandle string) (garden.Process, error)
}

type PeaUsernameResolver

type PeaUsernameResolver interface {
	ResolveUser(log lager.Logger, handle string, image garden.ImageRef, username string) (int, int, error)
}

type ProcessesStopper

type ProcessesStopper interface {
	StopAll(log lager.Logger, cgroupName string, save []int, kill bool) error
}

type Properties

type Properties interface {
	Set(handle string, key string, value string)
	Get(handle string, key string) (string, bool)
}

type RuntimeStopper

type RuntimeStopper interface {
	Stop() error
}

type State

type State struct {
	Pid    int
	Status Status
}

type StateStore

type StateStore interface {
	StoreStopped(handle string)
	IsStopped(handle string) bool
}

type Status

type Status string

const CreatedStatus Status = "created"

const RunningStatus Status = "running"

const StoppedStatus Status = "stopped"