The gnt-node and gnt-instance list commands have a customizable list of
output fields, but the list is not up to date (in the man page) and not
easily understandable from the ‘--help’ output.

This patch updates the man pages and adds the available fields and
default fields in the ‘--help’ output, as part of the description.

Example:
Usage
=====
  gnt-node list

Lists the nodes in the cluster. The available fields are (see the man page for
details): name, pinst_cnt, pinst_list, sinst_cnt, sinst_list, pip, sip,
dtotal, dfree, mtotal, mnode, mfree, bootid. The default field list is (in
order): name, dtotal, dfree, mtotal, mnode, mfree, pinst_cnt, sinst_cnt.

Reviewed-by: imsnah,ultrotter

It was wrongly deleted when converting

if a in dict.keys():
to
if a in dict:

Reviewed-by: imsnah

Passing a new aliases dict to generic main we can easily support aliases for
compatibility reasons or simply useability.

Reviewed-by: iustinp

When waiting for the lock and pressing ^C, the user will get a backtrace
as the KeyboardInterrupt exception is not handled. The patch adds a
simple method of handling it.

Note that this is not about ^C in any other place.

Reviewed-by: schreiberal,imsnah

This patch adds logging of command failures to the debug log in case the
user either started the command (gnt-*) or the node daemon with the
debug flag.

Reviewed-by: imsnah

Replace --secondary-node option with an optional parameter for --node.

Reviewed-by: ultrotter

This patch fixes some minor pylint warnings (unused variables, wrong
indentation, etc.) and a real bug in the recovery for drbd8 rename
procedure.

Reviewed-by: imsnah

This patch moves the passing of the feedback_fn argument from the
(Exec|Chain)OpCode to the initialization of the Processor instance.

Reviewed-by: imsnah

This adds:
  - fix the case when a dumb caller didn't stringify its values
  - explicitly raise a ProgrammerError in case a field is missing from
    the headers dictionary

Reviewed-by: imsnah

Currently, AskUser dies with -ESPIPE if the user gives more than one
character plus newline. This is because the python library, while
returning only two chars from the readline(2) call, will cache the rest
of the input, and when we do a write, it will try to seek back to just
after the last returned char. This fails on /dev/tty, so an exception is
raised. However, then opening the file descriptor in O_APPEND mode,
python will not issue such seeks, thereby fixing this problem.

The other alternative, opening in unbuffered mode, is not as good, since
then python will issue one-byte reads at a time, but the tty will read
the entire line, so at the next readline call, whatever remained in the
descriptor buffer is returned from the kernel to python, and the user
doesn't get a chance to enter something at all.

Reviewed-by: imsnah

Since modules are not directly executables, remove the shebang from
them. This helps with lintian warnings.

Also make the autogenerated _autoconf.py contain two comment lines at
the beginning, like the other modules.

Reviewed-by: ultrotter

This was introduced in rev 208.

Reviewed-by: imsnah

This patch moves the error formatting into a separate function that will
be exported so that scripts that execute multiple opcodes can create the
same output as for GenericMain. Also, GenericMain becomes more readable.

Reviewed-by: imsnah

This patch allows the SubmitOpcode function to take a pre-created
Processor instance and a different feedback function. This is helpful
when submitting more than one opcode from a shell script.

Reviewed-by: imsnah

This patch adds a simple handler for TagError that prints the error
(better than having a stack dump).

Reviewed-by: imsnah

This patch adds a '--from' option to the {add,remove}-tags commands that
allows the command to read from a file or from stdin (when passing a
dash for the filename).

Reviewed-by: imsnah

This patch adds generic functions for tag manipulations to cli.py and
modifies gnt-{cluster,node,instance} to export {list,add,remove}-tags
commands that use those.

Reviewed-by: imsnah

This allows scripts to pass options to generic functions (options that
are not visible in the command line).

Reviewed-by: imsnah

We currently require that hostnames are FQDN not short names
(node1.example.com instead of node1). We can allow short names as long
as:
  - we always resolve the names as returned by socket.gethostname()
  - we rely on having a working resolver

These issues are not as big as may seem, as we only did gethostname() in
a few places in order to check for the master; we already required
working resolver all over the code for the other nodes names (and thus
requiring the same for the current node name is normal).  The patch
moves some resolver calls from within execution path to the checking
path (which can abort without any problems). It is important that after
this patch is applied, no name resolving is called from the execution
path (LU.Exec() or other code that is called from within those methods)
as in this case we get much better code flow.

This patch also changes the functions for doing name lookups and
encapsulates all functionality in a single class.

The final change is that, by requiring working resolver at all times, we
can change the 'return None' into an exception and thus we don't have to
check manually each time; only some special cases will check
(ganeti-daemon and ganeti-watcher which are not covered by the
generalized exception handling in cli.py). The code is cleaner this way.

Reviewed-by: imsnah

This patch improves the AskUser function by allowing it to:
 - choose from multiple choices (instead of only y/n)
 - give help to the user
 - preserve line breaks and whitespace formatting in the message

With this patch, an instance removal looks like this:
root@xen-test1-4:~# gnt-instance remove tsetest1
This will remove the volumes of the instance tsetest1 (including
mirrors), thus removing all the data of the instance. Continue?
y/[n]/?: ?
 y - Perform the operation
 n - Do not perform the operation

This will remove the volumes of the instance tsetest1 (including
mirrors), thus removing all the data of the instance. Continue?
y/[n]/?: y

The patch also removed the _ask_user member of the opts argument, since
external code was using it (and thus it makes no sense for it to be a
private member); now gnt-* scripts are using the AskUser function
directly.

Reviewed-by: ultrotter

Since the table generation might be useful elsewhere, let's change it to
return the data instead of directly printing it.

Its callers have also been updated.

Reviewed-by: imsnah

This changes the raising of exceptions from:
  raise Exception, value
to
  raise Exception(value)

as the first form will be removed in python-3000 and the second form is
preferred now.

The changes also involve a few cases of changing from raising standard
exceptions and use our own ones.

The new version also fixes many pylint-generated warnings, especially in
ganeti-noded where I changed many methods to @staticmethod.

There is no functionality changed (barring any bugs).

- Implement “gnt-instance reinstall”
- Fix two typos

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

- Create all --output options using a constant
- Put node checking code from opcodes into a single function
- Do the same for output fields

Reviewed-by: iustinp