In order to prevent errors with old, in-use DRBD minors, we check and
abort at create time if our minor is already in use. For this we need to
also modify DRBD8Status to be able to parse cs:Unconfigured devices.

Reviewed-by: ultrotter

This patch adds a tail file function, to be used for parsing and returning in
the job log OS installation failures.

Reviewed-by: ultrotter

Reviewed-by: ultrotter

This allows the install and reinstall instance to return (hopefully)
relevant log files from the OS create scripts.

Reviewed-by: ultrotter

This will record the failure cause in starting up the instance in the
job log (and thus to the user).

Reviewed-by: ultrotter

Commit 2302 only modified _CreateBlockDevOnPrimary to the new style
result, but _CreateBlockDevOnSecondary was forgotten. After the merger
of the two functions, _CreateBlockDevOnSecondary was taken as template
so we checked against old-style values, thus completely breaking error
handling.

Reviewed-by: imsnah

Instead of having the default live in the gnt-cluster script, we move it
to the constants file. The patch also fixes a typo on constants.py.

Reviewed-by: ultrotter

This patch replaces a few obvious uses of [instance.primary_node] +
list(instance.secondary_nodes) (or similar usage) with the new
instance.all_nodes.

Reviewed-by: ultrotter

Commit 2294 introduced a new instance.all_nodes property, which
unfortunately is working incorrectly for non-drbd instances.

This patch fixes it by making sure the primary node is always added to
the set, even before recursing over (any potential) children.

Reviewed-by: imsnah

We don't need to pre-create the node entries in lvmap, since they will
be created at recursion time.

Reviewed-by: ultrotter

Some callers of _CreateBlockDev need recursive behaviour, but not all.
The replace secondary first creates (manually) new LVs to ensure storage
is there, and then it creates the new DRBD. At this point, we need a
non-recursive call so that the LVs are not needlessly re-created.

This patch splits the single device creation into a separate function,
so that LUReplaceDisks can use it.

Reviewed-by: ultrotter

Since only two boolean parameters differ between these two functions, we
combine them as to have less code duplication. This will be needed in
the future as we will need to split off the recursive part off.

Reviewed-by: ultrotter

This allows errors to be visible at the user level instead of just node
daemon logs.

Reviewed-by: ultrotter

For future propagation of error messages from backend to cmdlib and to
the job log, just having True/False return from the disk creation
function is not enough.

This patch converts these functions (_CreateDisks, _CreateBlockDevOnXXX)
to raise exception on errors, and otherwise the return value is None.

Reviewed-by: ultrotter

Currently when creation LVM-based instances, we always get the
extremely-confusing message "ERROR Can't find LV /dev/xenvg/..." which
is actually expected. This behaviour was introduced before we had
UUID-style LV names, since at that point it was not a unexpected to have
such volumes laying around after a failed creation.

Today, it's much more of an error to see existing volumes, and it's
better to abort with a failure. Since bdev.LogicalVolume.Create() method
will raise an error in case it exists, we can remove this check in
backend before creating the device.

The Create methods for DRBD and FileStorage currently don't raise
exception, as behaviour is not very well defined here.

We also change some exception types raised in bdev so that all
exceptions raised by device creation are a subclass of GenericError.

Reviewed-by: ultrotter

Currently we use a different UUID for the _data and _meta volumes of a
DRBD disk. This is confusing as it's hard to associate the two in the
output of “lvs” or “gnt-node volumes”.

The patch changes so that they use the same prefix.

Reviewed-by: ultrotter

Due to deficiencies in our block device implementation, it is a must to
call SetDiskID on disks before passing them to remote nodes. Since in
export/import, we don't touch the disks themselves, this was not needed
before in this function.

However, since having instance symlinks, the correct ID is needed here
too, and with static minors it's a "must need". This reflects into
failed instance starts after migration and/or failover.

Reviewed-by: ultrotter

Since we often need the list of all nodes of an instance, we add a new
"all_nodes" property that returns all nodes of the instance, and we
switch secondary_nodes to a simpler implementation based on this new
function.

Reviewed-by: ultrotter

We need to pass the fully-qualified node to _CheckNodeOnline, not the short
one.

Reviewed-by: imsnah

This patch rewraps some comments to shorter lengths, changes
double-quotes to single-quotes inside triple-quoted docstrings for
better editor handling.

It also fixes some epydoc errors, namely invalid crossreferences (after
method rename), documentation for inexistent (removed) parameters, etc.

Reviewed-by: ultrotter

The source port/addr is currently logged three times for each
connection, and this is unnecessary. We change two log entries to debug,
since they are useful for precise timing, and we keep only one at INFO
level.

Reviewed-by: imsnah

This is forward port via copy (and not individual patches cherry-pick)
of the latest code on the 1.2 branch related to the migration.

The changes compared to 1.2 are the fact that we don't need the
IdentifyDisks step anymore (the drbd rpc calls are independent now), and
the rpc module improvements.

Reviewed-by: ultrotter

In replace disks to new secondary, since Attach (and therefore
call_blockdev_find) is not modifying the devices anymore, we need to
switch this LU to the new call_drbd_disconnect_net and
call_drbd_attach_net functions.

Due to the authentication needed in 2.0, we need to be more careful with
the activation order. In 1.2, we have the case that the new node was
directly activated with networking information, and could connect to the
primary while it was still connected or WFConnect to the old secondary.

In the new scheme, we:
  - create the new drbd in StandAlone mode
  - shutdown old secondary (primary becomes WFConnection)
  - disconnect primary (and thus it goes into StandAlone)
  - connect both primary and new secondary to network using the
    call_drbd_attach_net rpc

This should be safer, and is cleaner. This passes burnin.

Reviewed-by: ultrotter

This is a modified forward-port of DrbdNetReconfig and their associated
RPCs. In Ganeti 2.0, these functions will be used for two things:
  - live migration (as in 1.2)
  - and for other network reconfiguration tasks, since DRBD8.Attach()
    doesn't do them anymore

Because of the Attach() changes, we can now implement the
AttachNet/DisconnectNet functions as independent entities, and we don't
need the cache anymore.

Note these functions are copies of the latest 1.2 code, and not
cherry-picks of the (many) patches that went into 1.2.

Reviewed-by: ultrotter

Since now the Assemble function is different than Attach, we rename this
backend function to show that the intent is to fully assemble the device
(and it's always allowed to modify the device).

Reviewed-by: ultrotter

Currently, both the Attach and Assemble methods for DRBD8 devices will use and
alter the device state. This is suboptimal, and it has been worked
around in 1.2 via a special cache in the node daemon so that we don't
need to call Attach() again in migration, for example.

Since in 2.0 we have static minors, we can change these functions so
that:
  - Attach() does not affect the device in any way, and only checks if
    the minor is already in use or not
  - Assemble() has two logic paths, one for startup from unused minor
    (the old Assemble, now renamed _FastAssemble) and one for
    re-checking/fixing an in-use minor (the old Attach, now renamed
    _SlowAttach)

Basically Attach was renamed to _SlowAttach, Assemble to _FastAssemble,
and we have a new, simple Assemble that calls one or the other based on
the result of the new Attach.

The LUReplaceDisks (with new secondary) is relying on the special
semantics of Attach modifying the device and is broken until the end of
the patch series.

Reviewed-by: ultrotter

The caller of dev.Assemble() (backend._RecursiveAssembleBD) is doing an
explicit recursion over all the children of the device, with better
error reporting. As such, we don't need this repeated assembly inside
the base BlockDev class.

Reviewed-by: ultrotter

... as found by the QA script - bug was introduced by me in commit 2117.

Reviwed-by: imsnah

This is a forward-port of commit 2219 on the 1.2 branch.

Reviewed-by: ultrotter

This patch makes gnt-cluster copyfile and command skip the offline
nodes.

Reviwed-by: ultrotter, imsnah

The RpcResult introduction still left some bugs (after multiple patches):
  - we don't correctly check the result type
  - rename a variable to prevent a conflict

Reviewed-by: imsnah

The checking for invalid instance names in LUQueryInstanceData is broken
since commit 1642.

Reviewed-by: imsnah

This LU can be used to force a push of the config in case it's needed,
for example after an upgrade to update the ssconf_release_version file.

Reviewed-by: imsnah

The patch adds a new ssconf file containing the ganeti version.

Reviewed-by: imsnah

This is modified forward-port of commit 1544 on the 1.2 branch:

  When DRBD is doing its dance to establish a connection with its
  peer, it also sends the synchronization speed over the wire. In
  some cases setting the sync speed only after setting up both
  sides can race with DRBD connecting, hence we set it here before
  telling DRBD anything about its peer.

  Reviewed-by: iustinp

The modification we make is that we split SetSyncSpeed in two so that we
don't need to modify our minor temporarily, and the fact that we call
this function from within _AssembleNet (right before enabling network),
instead of Assemble()/Attach().

Original-Author: imsnah

This patch updates burnin to the latest replace disks constant, and
changes the constants' values to be more accurate.

Reviewed-by: imsnah

We shouldn't query offline nodes in gnt-os. This patch adds an utility
function to ConfigWriter that returns the names of online nodes and uses
it in LUDiagnoseOS to query only the good nodes.

Reviewed-by: imsnah

The warning in node list is meant for nodes that return wrong
information, but for offline nodes this case is normal.

Reviewed-by: imsnah

The current fork+close fds sequence has deficiencies which are hard to
work around:
  - logging can start logging before we fork (e.g. if we need to emit
    messages related to master checking), and thus use FDs which we
    can't track nicely
  - the queue locks the queue file, and again this fd needs to be kept
    open which is hard from the main loop (and this error is currently
    hidden by the fact that we don't log it)

Given the above, it's much simpler, in case we will fork later, to close
file descriptors right at the beginning of the program, and in Daemonize
only close/reopen the stdin/out/err fds.

In addition, we also close() the handlers we remove in SetupLogging so
that the cleanup is more thorough.

Reviewed-by: imsnah

In 1.2, due to the md+drbd7 legacy, we had a complex choice of replace
modes, and the new drbd8 modes where forced into this syntax, with some
complicated rules of transition from one mode to another (if REPLACE_ALL
but not new node passed, switch to REPLACE_SEC, etc.).

This patch cleans this situation by making a clear separation between
the two main modes:
  - replace on current nodes (with the two sub-cases on primary and on
    secondary)
  - change to a new node (either via manually specified node or via
    iallocator)

Reviewed-by: imsnah