This patch adds a new, unused for now, parameter to the start and stop
master operations in backend. The idea behind it is that we need to be
able to control whether the IP (de)activation is coupled with daemon
startup/shutdown.

The callers are also modified to pass this parameter (even if unused for
now).

Reviewed-by: ultrotter

Reviewed-by: iustinp

The passed parameters were not correct.

Reviewed-by: iustinp, ultrotter

Reviewed-by: imsnah

Reviewed-by: imsnah

We cannot depend on all environments to have a start-stop-daemon or
similar tool. We instead implement a KillProcess function that behaves
similar to “start-stop-daemon --retry”.

Note that the attached unittest can hang in foreground if the child
misbehaves (doesn't write to the internal pipe). Since unittest are
either run in the foreground or are run with a timeout from an automated
framework, I think this is an acceptable trade-off (against of using
hardcoded timeouts in the test).

Reviewed-by: imsnah

We already have a function to test if a PID is alive, so it makes more
sense to use function composition that force calling (since we need to
read PIDs from files in other places too). Now IsProcessAlive returns
False for PIDs <= 0, since this is the error return from ReadPidFile.

The patch also adds a unittest for checking that WriteFile raises the
correct exception, and checks that an invalid or missing file causes
ReadPidFile to return zero. The unittest tearDown method will try to
cleanup the temp directory too (otherwise it leaves stuff after it).

Reviewed-by: ultrotter

This is needed for controlling it cleanly with start-stop daemon.

Reviewed-by: ultrotter

The RESTHTTPServer module went the way of the dodo.

Reviewed-by: iustinp

Reviewed-by: iustinp

All other daemons have their main code in themselves and not in a module.
This patch does the same to ganeti-rapi by moving the code from
lib/rapi/RESTHTTPServer.py to daemons/ganeti-rapi.

Reviewed-by: iustinp

The generic HTTP server doesn't know about httperror based exceptions
and would treat them as unknown exceptions, thereby not doing the right
thing with HTTP errors.

Reviewed-by: iustinp

Reviewed-by: ultrotter

Locking is not completeley right due to a deadlock when the job calls
UpdateJob after changing its status.

Reviewed-by: ultrotter

Reviewed-by: iustinp

Reviewed-by: ultrotter

The old API is no longer working.

Reviewed-by: ultrotter

It might come in handy at some point and makes the code a bit easier
to read.

Reviewed-by: iustinp

The set triggers exception on a list-tags command and RAPI calls for tags
since it is not serializable by JSON.

Reviewed-by: iustinp

Reviewed-by: imsnah

Reviewed-by: iustinp

So far no error reporting to the client is done. Clients don't get
noticed if a job doesn't exist or couldn't be archived because of
its current status.

The internal cache is always cleaned when the preconditions didn't
fail to make sure that the actual disk status will be reread next
time.

Reviewed-by: iustinp

Reviewed-by: iustinp

They aren't be tuples on the client side.

Reviewed-by: iustinp

The submitted WritePidFile, RemovePidfile and IsPidFileAlive functions
miss unit tests. Adding a simple one which covers their basic
functionality.

Reviewed-by: iustinp

A later patch will add a memory based job storage class, hence this
code is going into a separate class. It also changes the number format
to always use at least 10 digits, allowing up to 9'999'999'999 jobs to
be sorted without using a custom function.

Reviewed-by: iustinp

Rather than searching for the ganeti daemons by name we'll use the
pidfile they create to stop them. This change also adds the --oknodo
option to start-stop-daemon when stopping ganeti (which means it won't
give an error if it wasn't started).

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

WritePidFile is a helper function that writes the current pid in a
pidfile within the ganeti run directory. RemovePidFile tries to delete
it.

Reviewed-by: iustinp

This helper function reads a pid from a file containing it and checks
whether it refers to a live process.

Reviewed-by: iustinp

An implementation mistake from the original design caused nodes to be
locked before instances, rather than after. This patch inverts the level
numbering, changing also the relevant unittests and the recursive
locking function starting point.

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

The job ID is now a string, hence logging must use %s instead of %d.

Reviewed-by: iustinp

We can use zip for simplifying this function. Actually, at this point
I'm not sure if it needs to be a separate function at all.

Reviewed-by: imsnah

The docstring says that _NewSerialUnlocked returns “a string
representing the job identifier”. Until now it returned an
integer and this patch changes it.

Reviewed-by: iustinp

This patch adds distribution of the queue serial file after each write
to it (but before a new job is created and written with that ID, and
before a response is returned, so we should be safe from crashes in
between).

Currently it only logs if a node cannot be contacted, it should abort if
> 50% errors are seen.

Reviewed-by: imsnah

This will be needed for master failover. If we don't have a valid queue
directory, we need to reinitialize it, but we should keep the existing
serial number.

As such, we abstract the reading of the serial and if we find a valid
serial, we do not reset it.

Reviewed-by: imsnah