Currently, OpQueryNodes is locking all nodes (in shared mode), which
will also block the special case of querying only for the node names
(this is needed for gnt-cluster command, for example). There is no
logical requirement to not give the administrator enough power if she/he
knows what to do, so it would be logical that querying the node names
works without a lock.

The patch changes the LUQuerytNodes.ExpandNodes to only request locking
when the selected fields contain dynamic attributes, and a small change
in the Exec() method to use the new, atomic query method from
ConfigWriter.

Reviewed-by: ultrotter

The patch adds a new function to export all node information at once
(i.e. atomically with respect to the configuration lock).

Reviewed-by: ultrotter

Reviewed-by: iustinp

Otherwise, corruption could occur in some corner cases. E.g. when
LeaveNode is running in a child and is in the process of removing
queue files, the main process gets killed, started again and gets
a request to update the queue. This is rather extreme corner case,
but we should opt for safety.

Reviewed-by: iustinp

This is an initial version of the master startup checks. It's a very
rudimentary change, however in normal usage (an old master was started,
the rest of the cluster is functioning normally) it will succeed in
preventing wrong startups.

Reviewed-by: imsnah

We create a multi-node call so that querying all nodes for agreement
will be fast.

Reviewed-by: imsnah

The _GetMasterInfo() function needs to export the master name too to be
useful in master safety checks. This patch makes it a public (no _)
function and adds a third element in the return tuple. Its callers are
modified too.

Reviewed-by: imsnah

Reviewed-by: iustinp

These are two easy querying LUs which require shared access to all
nodes/instances.

Reviewed-by: iustinp

This is the most complex parallelization so far. We have to lock one
instance (and its nodes) plus one more node if doing a remote replace,
or all nodes if doing a remote replace with iallocator.

Reviewed-by: iustinp

This will be used to lock the instance's nodes in addition to some more.

Reviewed-by: iustinp

This function was incompatible with the new locking system, and its
usage has been removed from the code. For now LUs share code by calling
common module-private functions in cmdlib.py, in the future they will
use tasklets (when those will be implemented).

Reviewed-by: iustinp

Now that they are not used in other opcodes by chaining,
this can easily be done.

Reviewed-by: iustinp

The calls to OpActivateInstanceDisks and OpDeactivateInstanceDisks has
been replaced by _StartInstanceDisks and _SafeShutdownInstanceDisks
respectively. This is the last usage of ChainOpCode.

Reviewed-by: iustinp

This new function checks whether an instance is running, before shutting
down its disks. This is what the Exec() of LUDeactivateInstanceDisks
did, so that is replaced by a call to this function.

Reviewed-by: iustinp

s/locking.LEVEL_INSTANCES/locking.LEVEL_INSTANCE/

Reviewed-by: iustinp

This constant replaces what we used to write in recalculate_locks, and
represents the lock recalculation mode. It lives in constants.py because
it's used only in cmdlib, and thus doesn't deal with the locking library
by itself.

Reviewed-by: iustinp

self._RunAllocator() sets self.op.remote_node, but doesn't return the
new remote node. If we set it to the return value of the function we
basically reset it to None, and iallocator is never run.

Reviewed-by: imsnah

This helps to prevent complete deadlocks.

Reviewed-by: iustinp

The rpc library returns a list, not a tuple, so we'll accept both.

Reviewed-by: iustinp

The rpc library returns a list, not a tuple, so we'll accept both.

Reviewed-by: iustinp

Fixing the check in gnt-cluster, or gnt-cluster verify-disks is broken.
Since the version in 1.2 used to return a tuple we'll accept both.

Reviewed-by: iustinp

Unfortunately for the first version we need to lock all nodes. The patch
discusses why this is and discuss ways to improve this in the future.

Reviewed-by: iustinp

Reviewed-by: iustinp

When rebooting an instance and we're not changing it's disks status (all
the cases except in a "full" reboot) we can lock just its primary node.

Reviewed-by: iustinp

As the name says when the flag is on (the default is off) only the
primary nodes are locked, as opposed to all of them.

Reviewed-by: iustinp

The timeout can be used in ganeti-noded to be more robust against
deadlocks.

Reviewed-by: iustinp

Also change title formatting to match client-api.txt.

Reviewed-by: iustinp

Only one process should modify the queue at the same time.

Reviewed-by: iustinp

It didn't work as planned because some commands depend on the return
value or output of some operations.

Reviewed-by: iustinp

Rather than specifying None in needed_locks every time, with a nice
comment saying to read what we mean rather than what we write, and that
None actually means All, in our magic world, we'll hide this secret
under the ALL_SET constant in the locking module, which has value, you
guessed it, None. After that we'll substitute all usage in cmdlib.

Some comments and examples have been fixed as well.

Reviewed-by: iustinp

SplitTime didn't round the same on different platforms. This patch changes
it to use microseconds and not care about rounding.

Reviewed-by: iustinp

This is not nice, removing it :)

Please use 'set nobomb' in your vi init file.

Reviewed-by: ultrotter

All the users of _GetWantedNodes have been converted to be concurrent
LUs, and thus cannot call this function with an empty list of nodes
anymore. This patch makes this restriction a part of the function
itself. This prevents mistakes in new concurrent LUs, and creates more
work for new non-concurrent LUs, which we shouldn't add anyway.

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

It turns out this fields was already mandatory. If it hadn't beed valid,
in fact, a value of None would have been passed to _GetWantedNodes which
would have thrown an exception.

Reviewed-by: iustinp

Parallel opcodes are not (yet?) supported for chaining. Turns out
though that chaining is used only four times in the code, and twice it's
for querying exports. But what's the need to chain the full opcode, when
the simple call_export_list rpc is going to provide the same result?

Reviewed-by: iustinp

Reviewed-by: iustinp

Use a default vnc_bind_address if None is specified

Reviewed-by: iustinp