Grab a lock for the instance we're working on, and update its params.

Reviewed-by: iustinp

When we set the instance params we're not adding a new instance, but
just updating an existing one, so why using AddInstance?

Reviewed-by: iustinp

For ConnectConsole we just need to lock the instance we're connecting
to. We make a few rpcs to its primary node, but node daemons can now
handle multiple queries and nodes cannot be removed till they have
instances on them anyway. Note that since we return the ssh command, and
that's executed outside of the ganeti daemon, without any locks held,
the instance can then be subject to operations while we're connected to
it, but that was the previous behavior as well.

Reviewed-by: iustinp

LUs that take an instance name as input and need to expand its name and
lock it can use it to simplify their ExpandNames call. Possibly, and
_ExpandAndLockNode will come as well.

Reviewed-by: iustinp

LUQueryClusterInfo and LUDumpClusterConfig can be made concurrent and
don't need to acquire any locks. In fact they don't interact with the
cluster at all, but just with its configuration, which is thread-safe by
design.

Reviewed-by: iustinp

Two top level definitions were separated only by one empty line.
Fixing this.

Reviewed-by: imsnah

This removes (hopefully) all traces of the old locking functions and
uses.

Reviewed-by: imsnah

In order to do so:
  - We set REQ_BGL to False
  - We implement ExpandNames

That's it, really.

Reviewed-by: iustinp

New concurrent LUs will need to call ExpandNames so that any names
passed in by the user are canonicalized, and can be used by hooks,
locking and other parts of the code. This was done in CheckPrereq
before, but it's now splitted out, as it's needed for locking, which in
turn CheckPrereq needs. Old LUs can be converted gradually.

Reviewed-by: iustinp

cmdlib uses some constants from locking (ie. locking levels) but doesn't
import it. This patch fixes the issue.

Reviewed-by: iustinp

Since the context is passed to LogicalUnit, rather than the cfg, we can
only access the cfg as self.cfg, self.context.cfg, or context.cfg (in
the constructor). cfg is not valid anymore.

Reviewed-by: iustinp

Whenever we add an instance or node to the cluster (i.e. to the config
and whenever we remove them we should add/remove locks as well). In the
future we may want to optimize this so that the configwriter does it, or
it's handled at the context level, but till we're adding/removing
instances and nodes with the BGL held it doesn't matter too much.

Reviewed-by: iustinp

Rather than passing a ConfigWriter to the LUs we'll pass the whole
context, from which a ConfigWriter can be extracted, but we can also
access the GanetiLockManager. This also fixes the places where a FakeLU
is created.

Reviewed-by: iustinp

Reviewed-by: iustinp

When logical units have REQ_BGL set (it is currently the default) they
need to be the only ganeti operation run on the cluster, and we'll
guarantee it at the master daemon level. Currently only one thread is
running at a time, so this requirement is never broken.

Reviewed-by: iustinp

From the master node we can't start ssh and connect to the remote node,
nor we can do it from ganeti-noded as this ssh section will possibly ask
for key confirmation and password. So the code to copy the ganeti-noded
password and SSL key has been moved to bootstrap.py, and it's called by
gnt-node before the AddNode opcode.

Reviewed-by: iustinp

As we can't use ssh.VerifyNodeHostname directly, we'll set up a mini
node-verify to do checking between the master and the new node. In the
future networking checks, or more nodes, can be added as well.

Reviewed-by: iustinp

Since we're inside a LU we have access to self.sstore.
No need to use ss, which separate instantiation will disappear in a few
patches! ;)

Reviewed-by: iustinp

We used to scp all the ssconf files, and the vnc password file to the
new node. With this patch we use the upload_file rpc, specifying just
the new node as a destination. All the files previously copied by scp
are already allowed by the backend.

Reviewed-by: iustinp

Two LUs are using RunCmd to call fping, in order to check for an IP
presence on the network. Substituting it with TcpPing will get rid of
it, which makes it not break in the new world order, where the master
cannot fork.

Reviewed-by: iustinp

Even in 1.2 this behaviour is broken, as the rpc call will remove the
ssh keys before we get a chance to log in. Now the rpc takes care of
shutting down the node daemon as well, so we definitely can avoid this.

This makes the LURemoveNode operation work again with the threaded
master daemon.

Reviewed-by: iustinp

There is no point in checking whether the cluster VNC password file
exists as a prerequisite for AddNode, considering the check happens on
the master node, not the target one. Removing this check.

Reviewed-by: iustinp

Reviewed-by: iustinp

Apparently there were still some leftovers. While removing an instance,
I got the message "unhandled exception 'module' object has no attribute
'LD_MD_R1'".

Reviewed-by: iustinp

Since the disabling of forking in the master daemon, the two ssh-based
subcommands were not working anymore. However, there is no need at all
for the commands to be run from the master daemon (permissions to read
the cluster private ssh key notwithstanding), they can be run directly
from the command line utilities.

The patch removes the two opcodes OpRunClusterCommand and
OpClusterCopyFile (and their associated LUs) and changes the code in
‘gnt-cluster’ to query the list of nodes and run directly the SshRunner
over the list. As such, all forking is done from the gnt-cluster script,
and the commands are working again.

Reviewed-by: imsnah

Currently there isn't any easy way to list all nodes or instance and
their tags; you have to query each node in turn, or list all the tags
via something like “gnt-cluster search-tags '.*'”. Of course, this is
not optimal.

The patch adds a new fields to “gnt-instance list” and “gnt-node list”
called ‘tags’, that will list the tags of the object in comma-separated
form. This field will be empty if there are no tags (when using a
separator this output can still be parsed by other scripts).

At opcode level, there is a new fields called ‘tags’ that returns a
(python) list of the object tags.

Reviewed-by: ultrotter

There is a mistake in handling grow-disk for an invalid disk. This patch
fixes it.

Reviewed-by: imsnah

This patch adds a new opcode and LU for growing an instance's disk.

The opcode allows growing only one disk at time, and will throw an error
if the operation fails midway (e.g. on the primary node after it has
been increased on the secondary node). As such, it might actually leave
different sized LVs on different nodes, but this will not create
problems.

Reviewed-by: imsnah

Before we used to be able to update SimpleStore by just calling SetKey, this
feature is now moved to an external class, which inherits from it. In this
patch the new WritableSimpleStore class is also put to use, in the LUs that
need it. Rather than making each LU instantiate it, we have a new LogicalUnit
flag REQ_WSSTORE which defaults to False, but when declared to be True asks the
LogicalUnit to be initialized with a writeable version of the SimpleStore.
LUMasterFailover and LURenameCluster are then changed to use it.

InitCluster is also changed to instantiate a WritableSimpleStore, rather
than a normal one.

Reviewed-by: imsnah

When replacing disks or evacuating nodes with instances administratively
down ganeti fails because the instance disks are not active. This patch
activates them, performs the replacement, and shuts them down again.
Changing this also fixes the same issue on gnt-node evacuate.

Reviewed-by: iustinp

We're not adding a new instance, just making configuration changes to
the one we're working on.

Reviewed-by: imsnah

There is a mistake in the error message generated when we can't reach a
node for checking for available disk space. Without it, the error
message is:
Failure: prerequisites not met for this operation:
Cannot get current information from node '{u'gnte2.lab.k1024.org':
{'cpu_total': 1, 'memory_free': 480, 'vg_size': 131068, 'memory_total':
504, 'bootid': '2176dd3b-2f96-42f0-8b6e-2873ecaf5f9c', 'memory_dom0':
134, 'vg_free': 130172}, u'gnte1.lab.k1024.org': False}'

instead of the expected:
Failure: prerequisites not met for this operation:
Cannot get current information from node 'gnte2.lab.k1024.org'

Reviewed-by: imsnah

This allows us to initialize a new cluster. The code certainly contains
bugs and hooks aren't implemented yet.

Reviewed-by: iustinp

This is required for splitting the cluster initialization code.

Reviewed-by: iustinp

This is required for the split of the cluster initialization code.

Reviewed-by: iustinp, ultrotter

It's not needed anymore now that all opcodes require a cluster. Cluster
initialization was the only exception.

Reviewed-by: iustinp

Currently the check for enough memory is done only on instance start
command and failover command. But we also start an instance in instance
create, therefore we need to check this instead of failing to start in
the hypervisor phase.

The patch adds a check for node memory in the case the creation command
specifies that the instance should be started. It is allowed for the
memory to be less than needed if the instance will not be started, in
order to allow migration and other such cases.

Reviewed-by: imsnah

Author: schreiberal
Reviewed-by: iustinp

This fixes gnt-instance modify so it actually works with the
new HVM parameters for Ganeti 1.2

Author: schreiberal
Reviewed-by: iustinp

This patch modifies the code for "gnt-instance info .." to only display
instance parameters that actually apply to that instance, i.e. for PVM
instances no HVM parameters are shown and vice versa.

Author: schreiberal
Reviewed-by: iustinp