Package ganeti :: Module cmdlib :: Class LUQueryInstanceData
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Class LUQueryInstanceData

source code


Query runtime instance data.

Instance Methods [hide private]
 
ExpandNames(self)
Expand names for this LU.
source code
 
DeclareLocks(self, level)
Declare LU locking needs for a level
source code
 
CheckPrereq(self)
Check prerequisites.
source code
 
_ComputeBlockdevStatus(self, node, instance_name, dev)
Returns the status of a block device
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_ComputeDiskStatus(self, instance, snode, dev)
Compute block device status.
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Exec(self, feedback_fn)
Gather and return data
source code

Inherited from NoHooksLU: BuildHooksEnv

Inherited from LogicalUnit: CheckArguments, HooksCallBack, __init__

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

Class Variables [hide private]
  _OP_PARAMS = [("instances", _EmptyList, _TListOf(_TNonEmptyStr...
a list of opcode attributes, their defaults values they should get if not already defined, and types they must match
  REQ_BGL = False

Inherited from NoHooksLU: HPATH, HTYPE

Inherited from LogicalUnit: ssh

Instance Variables [hide private]

Inherited from LogicalUnit: dry_run_result

Properties [hide private]

Inherited from object: __class__

Method Details [hide private]

ExpandNames(self)

source code 

Expand names for this LU.

This method is called before starting to execute the opcode, and it should update all the parameters of the opcode to their canonical form (e.g. a short node name must be fully expanded after this method has successfully completed). This way locking, hooks, logging, ecc. can work correctly.

LUs which implement this method must also populate the self.needed_locks member, as a dict with lock levels as keys, and a list of needed lock names as values. Rules:

  • use an empty dict if you don't need any lock
  • if you don't need any lock at a particular level omit that level
  • don't put anything for the BGL level
  • if you want all locks at a level use locking.ALL_SET as a value

If you need to share locks (rather than acquire them exclusively) at one level you can modify self.share_locks, setting a true value (usually 1) for that level. By default locks are not shared.

This function can also define a list of tasklets, which then will be executed in order instead of the usual LU-level CheckPrereq and Exec functions, if those are not defined by the LU.

Examples:

 # Acquire all nodes and one instance
 self.needed_locks = {
   locking.LEVEL_NODE: locking.ALL_SET,
   locking.LEVEL_INSTANCE: ['instance1.example.com'],
 }
 # Acquire just two nodes
 self.needed_locks = {
   locking.LEVEL_NODE: ['node1.example.com', 'node2.example.com'],
 }
 # Acquire no locks
 self.needed_locks = {} # No, you can't leave it to the default value None
Overrides: LogicalUnit.ExpandNames
(inherited documentation)

DeclareLocks(self, level)

source code 

Declare LU locking needs for a level

While most LUs can just declare their locking needs at ExpandNames time, sometimes there's the need to calculate some locks after having acquired the ones before. This function is called just before acquiring locks at a particular level, but after acquiring the ones at lower levels, and permits such calculations. It can be used to modify self.needed_locks, and by default it does nothing.

This function is only called if you have something already set in self.needed_locks for the level.

Parameters:
  • level - Locking level which is going to be locked
Overrides: LogicalUnit.DeclareLocks
(inherited documentation)

CheckPrereq(self)

source code 

Check prerequisites.

This only checks the optional instance list against the existing names.

Overrides: LogicalUnit.CheckPrereq

Exec(self, feedback_fn)

source code 

Gather and return data

Overrides: LogicalUnit.Exec

Class Variable Details [hide private]

_OP_PARAMS

a list of opcode attributes, their defaults values they should get if not already defined, and types they must match
Value:
[("instances", _EmptyList, _TListOf(_TNonEmptyString)), ("static", Fal\
se, _TBool),]