mount

Documentation

Overview

Package mount defines an interface to mounting filesystems.

TODO(thockin): This whole pkg is pretty linux-centric. As soon as we have an alternate platform, we will need to abstract further.

Index

• Constants
• func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, error)
• func GetMountRefs(mounter Interface, mountPath string) ([]string, error)
• func IsNotMountPoint(file string) (bool, error)
• type FakeAction
• type FakeMounter
  • func (f *FakeMounter) DeviceOpened(pathname string) (bool, error)
  • func (f *FakeMounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)
  • func (f *FakeMounter) IsLikelyNotMountPoint(file string) (bool, error)
  • func (f *FakeMounter) List() ([]MountPoint, error)
  • func (f *FakeMounter) Mount(source string, target string, fstype string, options []string) error
  • func (f *FakeMounter) PathIsDevice(pathname string) (bool, error)
  • func (f *FakeMounter) ResetLog()
  • func (f *FakeMounter) Unmount(target string) error
• type Interface
  • func New(mounterPath string) Interface
• type MountPoint
• type Mounter
  • func (mounter *Mounter) DeviceOpened(pathname string) (bool, error)
  • func (mounter *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)
  • func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error)
  • func (*Mounter) List() ([]MountPoint, error)
  • func (mounter *Mounter) Mount(source string, target string, fstype string, options []string) error
  • func (mounter *Mounter) PathIsDevice(pathname string) (bool, error)
  • func (mounter *Mounter) Unmount(target string) error
• type NsenterMounter
  • func NewNsenterMounter() *NsenterMounter
  • func (n *NsenterMounter) DeviceOpened(pathname string) (bool, error)
  • func (n *NsenterMounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)
  • func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error)
  • func (*NsenterMounter) List() ([]MountPoint, error)
  • func (n *NsenterMounter) Mount(source string, target string, fstype string, options []string) error
  • func (n *NsenterMounter) PathIsDevice(pathname string) (bool, error)
  • func (n *NsenterMounter) Unmount(target string) error
• type SafeFormatAndMount
  • func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string, fstype string, options []string) error

Constants

const FakeActionMount = "mount"

Values for FakeAction.Action

const FakeActionUnmount = "unmount"

const (
	MountsInGlobalPDPath = "mounts"
)

Functions

func GetDeviceNameFromMount

func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, error)

GetDeviceNameFromMount: given a mnt point, find the device from /proc/mounts returns the device name, reference count, and error code

func GetMountRefs

func GetMountRefs(mounter Interface, mountPath string) ([]string, error)

GetMountRefs finds all other references to the device referenced by mountPath; returns a list of paths.

func IsNotMountPoint

func IsNotMountPoint(file string) (bool, error)

Types

type FakeAction

type FakeAction struct {
	Action string // "mount" or "unmount"
	Target string // applies to both mount and unmount actions
	Source string // applies only to "mount" actions
	FSType string // applies only to "mount" actions
}

FakeAction objects are logged every time a fake mount or unmount is called.

type FakeMounter

type FakeMounter struct {
	MountPoints []MountPoint
	Log         []FakeAction
	// contains filtered or unexported fields
}

FakeMounter implements mount.Interface for tests.

func (*FakeMounter) DeviceOpened

func (f *FakeMounter) DeviceOpened(pathname string) (bool, error)

func (*FakeMounter) GetDeviceNameFromMount

func (f *FakeMounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)

func (*FakeMounter) IsLikelyNotMountPoint

func (f *FakeMounter) IsLikelyNotMountPoint(file string) (bool, error)

func (*FakeMounter) List

func (f *FakeMounter) List() ([]MountPoint, error)

func (*FakeMounter) Mount

func (f *FakeMounter) Mount(source string, target string, fstype string, options []string) error

func (*FakeMounter) PathIsDevice

func (f *FakeMounter) PathIsDevice(pathname string) (bool, error)

func (*FakeMounter) ResetLog

func (f *FakeMounter) ResetLog()

func (*FakeMounter) Unmount

func (f *FakeMounter) Unmount(target string) error

type Interface

type Interface interface {
	// Mount mounts source to target as fstype with given options.
	Mount(source string, target string, fstype string, options []string) error
	// Unmount unmounts given target.
	Unmount(target string) error
	// List returns a list of all mounted filesystems.  This can be large.
	// On some platforms, reading mounts is not guaranteed consistent (i.e.
	// it could change between chunked reads). This is guaranteed to be
	// consistent.
	List() ([]MountPoint, error)
	// IsLikelyNotMountPoint determines if a directory is a mountpoint.
	// It should return ErrNotExist when the directory does not exist.
	IsLikelyNotMountPoint(file string) (bool, error)
	// DeviceOpened determines if the device is in use elsewhere
	// on the system, i.e. still mounted.
	DeviceOpened(pathname string) (bool, error)
	// PathIsDevice determines if a path is a device.
	PathIsDevice(pathname string) (bool, error)
	// GetDeviceNameFromMount finds the device name by checking the mount path
	// to get the global mount path which matches its plugin directory
	GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)
}

func New

func New(mounterPath string) Interface

New returns a mount.Interface for the current system. It provides options to override the default mounter behavior. mounterPath allows using an alternative to `/bin/mount` for mounting.

type MountPoint

type MountPoint struct {
	Device string
	Path   string
	Type   string
	Opts   []string
	Freq   int
	Pass   int
}

This represents a single line in /proc/mounts or /etc/fstab.

type Mounter

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

Mounter provides the default implementation of mount.Interface for the linux platform. This implementation assumes that the kubelet is running in the host's root mount namespace.

func (*Mounter) DeviceOpened

func (mounter *Mounter) DeviceOpened(pathname string) (bool, error)

DeviceOpened checks if block device in use by calling Open with O_EXCL flag. If pathname is not a device, log and return false with nil error. If open returns errno EBUSY, return true with nil error. If open returns nil, return false with nil error. Otherwise, return false with error

func (*Mounter) GetDeviceNameFromMount

func (mounter *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)

GetDeviceNameFromMount: given a mount point, find the device name from its global mount point

func (*Mounter) IsLikelyNotMountPoint

func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error)

IsLikelyNotMountPoint determines if a directory is not a mountpoint. It is fast but not necessarily ALWAYS correct. If the path is in fact a bind mount from one part of a mount to another it will not be detected. mkdir /tmp/a /tmp/b; mount --bin /tmp/a /tmp/b; IsLikelyNotMountPoint("/tmp/b") will return true. When in fact /tmp/b is a mount point. If this situation if of interest to you, don't use this function...

func (*Mounter) List

func (*Mounter) List() ([]MountPoint, error)

List returns a list of all mounted filesystems.

func (*Mounter) Mount

func (mounter *Mounter) Mount(source string, target string, fstype string, options []string) error

Mount mounts source to target as fstype with given options. 'source' and 'fstype' must be an emtpy string in case it's not required, e.g. for remount, or for auto filesystem type, where kernel handles fs type for you. The mount 'options' is a list of options, currently come from mount(8), e.g. "ro", "remount", "bind", etc. If no more option is required, call Mount with an empty string list or nil.

func (*Mounter) PathIsDevice

func (mounter *Mounter) PathIsDevice(pathname string) (bool, error)

PathIsDevice uses FileInfo returned from os.Stat to check if path refers to a device.

func (*Mounter) Unmount

func (mounter *Mounter) Unmount(target string) error

Unmount unmounts the target.

type NsenterMounter

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

NsenterMounter is part of experimental support for running the kubelet in a container. Currently, all docker containers receive their own mount namespaces. NsenterMounter works by executing nsenter to run commands in the host's mount namespace.

NsenterMounter requires:

1. Docker >= 1.6 due to the dependency on the slave propagation mode of the bind-mount of the kubelet root directory in the container. Docker 1.5 used a private propagation mode for bind-mounts, so mounts performed in the host's mount namespace do not propagate out to the bind-mount in this docker version.
2. The host's root filesystem must be available at /rootfs
3. The nsenter binary must be on the Kubelet process' PATH in the container's filesystem.
4. The Kubelet process must have CAP_SYS_ADMIN (required by nsenter); at the present, this effectively means that the kubelet is running in a privileged container.
5. The volume path used by the Kubelet must be the same inside and outside the container and be writable by the container (to initialize volume) contents. TODO: remove this requirement.
6. The host image must have mount, findmnt, and umount binaries in /bin, /usr/sbin, or /usr/bin

For more information about mount propagation modes, see:

https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt

func NewNsenterMounter

func NewNsenterMounter() *NsenterMounter

func (*NsenterMounter) DeviceOpened

func (n *NsenterMounter) DeviceOpened(pathname string) (bool, error)

DeviceOpened checks if block device in use by calling Open with O_EXCL flag. Returns true if open returns errno EBUSY, and false if errno is nil. Returns an error if errno is any error other than EBUSY. Returns with error if pathname is not a device.

func (*NsenterMounter) GetDeviceNameFromMount

func (n *NsenterMounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)

GetDeviceNameFromMount given a mount point, find the volume id from checking /proc/mounts

func (*NsenterMounter) IsLikelyNotMountPoint

func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error)

IsLikelyNotMountPoint determines whether a path is a mountpoint by calling findmnt in the host's root mount namespace.

func (*NsenterMounter) List

func (*NsenterMounter) List() ([]MountPoint, error)

List returns a list of all mounted filesystems in the host's mount namespace.

func (*NsenterMounter) Mount

func (n *NsenterMounter) Mount(source string, target string, fstype string, options []string) error

Mount runs mount(8) in the host's root mount namespace. Aside from this aspect, Mount has the same semantics as the mounter returned by mount.New()

func (*NsenterMounter) PathIsDevice

func (n *NsenterMounter) PathIsDevice(pathname string) (bool, error)

PathIsDevice uses FileInfo returned from os.Stat to check if path refers to a device.

func (*NsenterMounter) Unmount

func (n *NsenterMounter) Unmount(target string) error

Unmount runs umount(8) in the host's mount namespace.

type SafeFormatAndMount

type SafeFormatAndMount struct {
	Interface
	Runner exec.Interface
}

SafeFormatAndMount probes a device to see if it is formatted. Namely it checks to see if a file system is present. If so it mounts it otherwise the device is formatted first then mounted.

func (*SafeFormatAndMount) FormatAndMount

func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string, fstype string, options []string) error

FormatAndMount formats the given disk, if needed, and mounts it. That is if the disk is not formatted and it is not being mounted as read-only it will format it first then mount it. Otherwise, if the disk is already formatted or it is being mounted as read-only, it will be mounted without formatting.