Package ganeti :: Module cmdlib :: Class TagsLU
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Class TagsLU

source code


Generic tags LU.

This is an abstract class which is the parent of all the other tags LUs.

Instance Methods [hide private]
 
ExpandNames(self)
Expand names for this LU.
source code
 
CheckPrereq(self)
Check prerequisites.
source code

Inherited from NoHooksLU: BuildHooksEnv

Inherited from LogicalUnit: CheckArguments, DeclareLocks, Exec, HooksCallBack, __init__

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

Class Variables [hide private]

Inherited from NoHooksLU: HPATH, HTYPE

Inherited from LogicalUnit: REQ_BGL, ssh

Inherited from LogicalUnit (private): _OP_PARAMS

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)

CheckPrereq(self)

source code 

Check prerequisites.

Overrides: LogicalUnit.CheckPrereq