overlay2

Documentation

Index

• func Init(home string, options []string, idMap idtools.IdentityMapping) (graphdriver.Driver, error)
• type Driver
  • func (d *Driver) ApplyDiff(id string, parent string, diff io.Reader) (size int64, err error)
  • func (d *Driver) Changes(id, parent string) ([]archive.Change, error)
  • func (d *Driver) Cleanup() error
  • func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) (retErr error)
  • func (d *Driver) CreateReadWrite(id, parent string, opts *graphdriver.CreateOpts) error
  • func (d *Driver) Diff(id, parent string) (io.ReadCloser, error)
  • func (d *Driver) DiffSize(id, parent string) (size int64, err error)
  • func (d *Driver) Exists(id string) bool
  • func (d *Driver) Get(id, mountLabel string) (_ string, retErr error)
  • func (d *Driver) GetMetadata(id string) (map[string]string, error)
  • func (d *Driver) Put(id string) error
  • func (d *Driver) Remove(id string) error
  • func (d *Driver) Status() [][2]string
  • func (d *Driver) String() string

Functions

func Init

func Init(home string, options []string, idMap idtools.IdentityMapping) (graphdriver.Driver, error)

Init returns the native diff driver for overlay filesystem. If overlay filesystem is not supported on the host, the error graphdriver.ErrNotSupported is returned. If an overlay filesystem is not supported over an existing filesystem then the error graphdriver.ErrIncompatibleFS is returned.

Types

type Driver

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

Driver contains information about the home directory and the list of active mounts that are created using this driver.

func (*Driver) ApplyDiff

func (d *Driver) ApplyDiff(id string, parent string, diff io.Reader) (size int64, err error)

ApplyDiff applies the new layer into a root

func (*Driver) Changes

func (d *Driver) Changes(id, parent string) ([]archive.Change, error)

Changes produces a list of changes between the specified layer and its parent layer. If parent is "", then all changes will be ADD changes.

func (*Driver) Cleanup

func (d *Driver) Cleanup() error

Cleanup any state created by overlay which should be cleaned when daemon is being shutdown. For now, we just have to unmount the bind mounted we had created.

func (*Driver) Create

func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) (retErr error)

Create is used to create the upper, lower, and merge directories required for overlay fs for a given id. The parent filesystem is used to configure these directories for the overlay.

func (*Driver) CreateReadWrite

func (d *Driver) CreateReadWrite(id, parent string, opts *graphdriver.CreateOpts) error

CreateReadWrite creates a layer that is writable for use as a container file system.

func (*Driver) Diff

func (d *Driver) Diff(id, parent string) (io.ReadCloser, error)

Diff produces an archive of the changes between the specified layer and its parent layer which may be "".

func (*Driver) DiffSize

func (d *Driver) DiffSize(id, parent string) (size int64, err error)

DiffSize calculates the changes between the specified id and its parent and returns the size in bytes of the changes relative to its base filesystem directory.

func (*Driver) Exists

func (d *Driver) Exists(id string) bool

Exists checks to see if the id is already mounted.

func (*Driver) Get

func (d *Driver) Get(id, mountLabel string) (_ string, retErr error)

Get creates and mounts the required file system for the given id and returns the mount path.

func (*Driver) GetMetadata

func (d *Driver) GetMetadata(id string) (map[string]string, error)

GetMetadata returns metadata about the overlay driver such as the LowerDir, UpperDir, WorkDir, and MergeDir used to store data.

func (*Driver) Put

func (d *Driver) Put(id string) error

Put unmounts the mount path created for the give id. It also removes the 'merged' directory to force the kernel to unmount the overlay mount in other namespaces.

func (*Driver) Remove

func (d *Driver) Remove(id string) error

Remove cleans the directories that are created for this id.

func (*Driver) Status

func (d *Driver) Status() [][2]string

Status returns current driver information in a two dimensional string array. Output contains "Backing Filesystem" used in this implementation.

func (*Driver) String

func (d *Driver) String() string