Package ganeti :: Module bdev :: Class DRBD8
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Class DRBD8

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DRBD v8.x block device.

This implements the local host part of the DRBD device, i.e. it doesn't do anything to the supposed peer. If you need a fully connected DRBD pair, you need to use this class on both hosts.

The unique_id for the drbd device is a (local_ip, local_port, remote_ip, remote_port, local_minor, secret) tuple, and it must have two children: the data device and the meta_device. The meta device is checked for valid size and is zeroed on create.

Instance Methods [hide private]
 
__init__(self, unique_id, children, size, params)
x.__init__(...) initializes x; see help(type(x)) for signature
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_MatchesLocal(self, info)
Test if our local config matches with an existing device.
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_MatchesNet(self, info)
Test if our network config matches with an existing device.
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_AssembleLocal(self, minor, backend, meta, size)
Configure the local part of a DRBD device.
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_AssembleNet(self, minor, net_info, protocol, dual_pri=False, hmac=None, secret=None)
Configure the network part of the device.
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AddChildren(self, devices)
Add a disk to the DRBD device.
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RemoveChildren(self, devices)
Detach the drbd device from local storage.
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list
SetSyncParams(self, params)
Set the synchronization parameters of the DRBD syncer.
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PauseResumeSync(self, pause)
Pauses or resumes the sync of a DRBD device.
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GetProcStatus(self)
Return device data from /proc.
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objects.BlockDevStatus
GetSyncStatus(self)
Returns the sync status of the device.
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Open(self, force=False)
Make the local state primary.
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Close(self)
Make the local state secondary.
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DisconnectNet(self)
Removes network configuration.
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AttachNet(self, multimaster)
Reconnects the network.
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Attach(self)
Check if our minor is configured.
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Assemble(self)
Assemble the drbd.
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_SlowAssemble(self)
Assembles the DRBD device from a (partially) configured device.
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_FastAssemble(self)
Assemble the drbd device from zero.
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Shutdown(self)
Shutdown the DRBD device.
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Remove(self)
Stub remove for DRBD devices.
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Grow(self, amount, dryrun, backingstore)
Resize the DRBD device and its backing storage.
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Inherited from BaseDRBD: Rename

Inherited from BaseDRBD (private): _SetFromMinor

Inherited from BlockDev: CombinedSyncStatus, GetActualSize, SetInfo, __repr__

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __setattr__, __sizeof__, __str__, __subclasshook__

Class Methods [hide private]
 
_InitMeta(cls, minor, dev_path)
Initialize a meta device.
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_FindUnusedMinor(cls)
Find an unused DRBD device.
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_GetShowParser(cls)
Return a parser for `drbd show` output.
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_GetShowData(cls, minor)
Return the `drbdsetup show` data for a minor.
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_GetDevInfo(cls, out)
Parse details about a given DRBD minor.
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_ComputeDiskBarrierArgs(cls, vmaj, vmin, vrel, disabled_barriers, disable_meta_flush)
Compute the DRBD command line parameters for disk barriers
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list
_SetMinorSyncParams(cls, minor, params)
Set the parameters of the DRBD syncer.
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_ShutdownLocal(cls, minor)
Detach from the local device.
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_ShutdownNet(cls, minor)
Disconnect from the remote peer.
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_ShutdownAll(cls, minor)
Deactivate the device.
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Create(cls, unique_id, children, size, params, excl_stor)
Create a new DRBD8 device.
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Inherited from BaseDRBD: GetUsedDevs

Inherited from BaseDRBD (private): _GetVersion, _MassageProcData

Static Methods [hide private]

Inherited from BaseDRBD: GetUsermodeHelper

Inherited from BaseDRBD (private): _CheckMetaSize, _DevPath, _GetProcData

Class Variables [hide private]
  _MAX_MINORS = 255
  _PARSE_SHOW = None
  _NET_RECONFIG_TIMEOUT = 60
  _DISABLE_DISK_OPTION = "--no-disk-barrier"
  _DISABLE_DRAIN_OPTION = "--no-disk-drain"
  _DISABLE_FLUSH_OPTION = "--no-disk-flushes"
  _DISABLE_META_FLUSH_OPTION = "--no-md-flushes"
Properties [hide private]

Inherited from object: __class__

Method Details [hide private]

__init__(self, unique_id, children, size, params)
(Constructor)

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x.__init__(...) initializes x; see help(type(x)) for signature

Overrides: object.__init__
(inherited documentation)

_InitMeta(cls, minor, dev_path)
Class Method

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Initialize a meta device.

This will not work if the given minor is in use.

_FindUnusedMinor(cls)
Class Method

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Find an unused DRBD device.

This is specific to 8.x as the minors are allocated dynamically, so non-existing numbers up to a max minor count are actually free.

_GetShowParser(cls)
Class Method

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Return a parser for `drbd show` output.

This will either create or return an already-created parser for the output of the command `drbd show`.

_GetDevInfo(cls, out)
Class Method

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Parse details about a given DRBD minor.

This return, if available, the local backing device (as a path) and the local and remote (ip, port) information from a string containing the output of the `drbdsetup show` command as returned by _GetShowData.

_MatchesLocal(self, info)

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Test if our local config matches with an existing device.

The parameter should be as returned from `_GetDevInfo()`. This method tests if our local backing device is the same as the one in the info parameter, in effect testing if we look like the given device.

_MatchesNet(self, info)

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Test if our network config matches with an existing device.

The parameter should be as returned from `_GetDevInfo()`. This method tests if our network configuration is the same as the one in the info parameter, in effect testing if we look like the given device.

_ComputeDiskBarrierArgs(cls, vmaj, vmin, vrel, disabled_barriers, disable_meta_flush)
Class Method

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Compute the DRBD command line parameters for disk barriers

Returns a list of the disk barrier parameters as requested via the disabled_barriers and disable_meta_flush arguments, and according to the supported ones in the DRBD version vmaj.vmin.vrel

If the desired option is unsupported, raises errors.BlockDeviceError.

_SetMinorSyncParams(cls, minor, params)
Class Method

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Set the parameters of the DRBD syncer.

This is the low-level implementation.

Parameters:
  • minor (int) - the drbd minor whose settings we change
  • params (dict) - LD level disk parameters related to the synchronization
Returns: list
a list of error messages

SetSyncParams(self, params)

source code 

Set the synchronization parameters of the DRBD syncer.

Parameters:
  • params (dict) - LD level disk parameters related to the synchronization
Returns: list
a list of error messages, emitted both by the current node and by children. An empty list means no errors
Overrides: BlockDev.SetSyncParams

PauseResumeSync(self, pause)

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Pauses or resumes the sync of a DRBD device.

Parameters:
  • pause - Wether to pause or resume
Returns:
the success of the operation
Overrides: BlockDev.PauseResumeSync

GetSyncStatus(self)

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Returns the sync status of the device.

If sync_percent is None, it means all is ok If estimated_time is None, it means we can't estimate the time needed, otherwise it's the time left in seconds.

We set the is_degraded parameter to True on two conditions: network not connected or local disk missing.

We compute the ldisk parameter based on whether we have a local disk or not.

Returns: objects.BlockDevStatus
Overrides: BlockDev.GetSyncStatus

Open(self, force=False)

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Make the local state primary.

If the 'force' parameter is given, the '-o' option is passed to drbdsetup. Since this is a potentially dangerous operation, the force flag should be only given after creation, when it actually is mandatory.

Overrides: BlockDev.Open

Close(self)

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Make the local state secondary.

This will, of course, fail if the device is in use.

Overrides: BlockDev.Close

DisconnectNet(self)

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Removes network configuration.

This method shutdowns the network side of the device.

The method will wait up to a hardcoded timeout for the device to go into standalone after the 'disconnect' command before re-configuring it, as sometimes it takes a while for the disconnect to actually propagate and thus we might issue a 'net' command while the device is still connected. If the device will still be attached to the network and we time out, we raise an exception.

AttachNet(self, multimaster)

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Reconnects the network.

This method connects the network side of the device with a specified multi-master flag. The device needs to be 'Standalone' but have valid network configuration data.

Args:

  • multimaster: init the network in dual-primary mode

Attach(self)

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Check if our minor is configured.

This doesn't do any device configurations - it only checks if the minor is in a state different from Unconfigured.

Note that this function will not change the state of the system in any way (except in case of side-effects caused by reading from /proc).

Overrides: BlockDev.Attach

Assemble(self)

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Assemble the drbd.

Method:

  • if we have a configured device, we try to ensure that it matches our config
  • if not, we create it from zero
  • anyway, set the device parameters
Overrides: BlockDev.Assemble

_SlowAssemble(self)

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Assembles the DRBD device from a (partially) configured device.

In case of partially attached (local device matches but no network setup), we perform the network attach. If successful, we re-test the attach if can return success.

_FastAssemble(self)

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Assemble the drbd device from zero.

This is run when in Assemble we detect our minor is unused.

_ShutdownLocal(cls, minor)
Class Method

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Detach from the local device.

I/Os will continue to be served from the remote device. If we don't have a remote device, this operation will fail.

_ShutdownNet(cls, minor)
Class Method

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Disconnect from the remote peer.

This fails if we don't have a local device.

_ShutdownAll(cls, minor)
Class Method

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Deactivate the device.

This will, of course, fail if the device is in use.

Shutdown(self)

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Shutdown the DRBD device.

Overrides: BlockDev.Shutdown

Remove(self)

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Stub remove for DRBD devices.

Overrides: BlockDev.Remove

Create(cls, unique_id, children, size, params, excl_stor)
Class Method

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Create a new DRBD8 device.

Since DRBD devices are not created per se, just assembled, this function only initializes the metadata.

Overrides: BlockDev.Create

Grow(self, amount, dryrun, backingstore)

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Resize the DRBD device and its backing storage.

Parameters:
  • amount - the amount (in mebibytes) to grow with
  • dryrun - whether to execute the operation in simulation mode only, without actually increasing the size
  • backingstore - whether to execute the operation on backing storage only, or on "logical" storage only; e.g. DRBD is logical storage, whereas LVM, file, RBD are backing storage
Overrides: BlockDev.Grow