This patch changes Cluster.totalResources to compute more resources and
prints them in hspace.

Currently the cluster score calculation includes an offline instance
percentage, expressed as “offline inst / (offline + online inst)”, which
results in NaN for empty clusters. This patch changes the calculation
such that clusters with no offline instances (this criteria includes
completely empty clusters) get a score of zero on this component of the
total score.

This patch changes the function Cluster.computeMoves to use guards and a
couple of subexpressions in order to greatly simplify it.

This big patch cleans up the code per hlint indications. Many removals
of extra parentheses, replacements of concat . map with concabtMap,
extra dollar signs, eta reductions, etc. were performed.

The code still compiles and passes a couple of manual tests on sample
files. The individual changes are also small enough as to be visually
easy to confirm.

Currently the allocation/move operations workflow return ‘Maybe a’,
which is very convenient but loses all details about the failure mode.

This patch introduces a new data type which encodes the specific failure
mode. It is not yet used correctly (e.g. all node operations result in
FailN1), but the workflow is updated. Most of the changes are in the
hail/hspace tools, the library code required only trivial adjustments.

hn1 was deprecated for a while and this patch removes it altogether. The
support code in Cluster.hs is also removed.

This uses the newly-added Node.availDisk to compute the actual available
disk correctl, and display the total allocatable disk in hspace.

Currently totalResources returns a 5-tuple of integers. This is not easy
to handle, as each change on the return type means that each caller must
be updated.

This patch adds a new type for cluster stats and uses that instead as
its return type. This simplifies its callers while complicating only a
little the computation of the stats.

This patch changes Cluster.totalResources to compute more details about
the cluster status, and enhances hspace to display more of these.

In a few places (e.g. tryRead or any printf call) it's a little bit hard
to add the correct type signatures, but in the it is possible to fix
these warnings (which can bite one in subtle cases).

This is just some cleanup of the node list output, adding pcpu/vcpu
counters, and making the display slightly nicer.

This patch adds cpu-count related attributes to nodes:
  - total cpus
  - cpus in use
  - ratio of virtual:physical cpus

We also set correctly the cpu values at load time, but we don't do
anything yet while moving instances around. The cpu ratio is shown in
the cluster list.

During a replace-primary instance move, on the real cluster the instance
is temporarily started on the secondary, and as such we must check that
the secondary node can hold it for this duration. Currently the code
does not, and depending on cluster scoring it will put instances on such
'bad' secondaries (usually without enough memory).

This patch fixes this by adding/removing the instance as a primary on
the secondary node; and then using the result node as the new secondary.
(Since we're in a monad, we could have just tried the allocation and
dropped the result, but this is more clear).

Currently tryAlloc/tryReloc do not return the new instance, as this is
not needed for IAllocator alloc/reloc requests. However, for computing
the space, the new instance is useful, so we modify these functions to
return this information too.

The patch also improves hspace to have (with default parameters) a
parseable output.

This doc-patch adds copyright and license information to (hopefully) all
needed files.

These are generic enough to be used from multiple places, they belong
better in Cluster.hs than in the hail source.

Also replace a type with its synonim.

This patch does only doc build changes, doc changes and function move
around (for more logical documentation). It should have no impact at all
on the code.

This is a first step towards full datatype renaming. That requires more
changes, so at first we only want to document clearly what is a node
index, what is an instance index, and what is a plain Int.

This patch makes the Types module a base module, and Node/Instance ones
import it, from the previous (opposite) situation. This will allow in
the future to use newtypes for the index and name types.

This patch implements non-mirrored instance allocation, by allocating as
secondary node “noSecondary”.

This patch implements allocate for two node requests. One node requests
can be done as soon as we have a valid allocateOn function for single
nodes.

This patch completes the implementation of hail relocate. It maps all
valid destination nodes through a ReplaceSecondary IMove, filters out
the failed relocations, computes the resulting scores and picks the
lowest one.

This patch removes all uses of ktn/kti from the past-loader stages.

Since we have Node/Instance.name, we can now simplify a few constructs.

This moves the remaining loading function to Loader (together with its
associated support functions).

This new big patch does a couple of more cleanups in the loading of data
chapter:
  - introduce a Types module that holds most types (except the base
    Node/Instance/etc.) so that multiple other modules can use these
    (instead of only Cluster and its users)
  - bring IAlloc.hs in line with the recent changes of providing data
    types and not strings
  - removal of obsolete Utils.hs json-related functions

This big patch changes the loader model from “string data as common
format” to actual object structures as common format.

The text loading function move from Cluster.hs to a new Text.hs module,
some common functions are moved to a new Loader.hs module, and the
return values from both Rapi.hs and Text.hs are uniformized.

This patch adds experimental support to hbal for non-redundant instances
(i.e.  instances with only one node). They are currently handled as
non-moveable, and as such the algorithm simply ignores them.

Supports needs to be added when reading from RAPI via hscan, and
probably in other corner cases.

This patch switches from plain read to a wrapper over readsPrec that
returns better error messages than the buildin 'Prelude: no parse'.

This allows easy checking for valid format of the input data (row-wise).

This patch converts loadTabular and loadData to a monadic form, thus
allowing meaningful error messages from the node/instance load routines.

This patch changes Cluster.loadData to return a Result, instead of
directly the values; this will allow us to return meaningful error
values (e.g. when an instances lives on unknown node) rather than simply
abort. Currently the result is always an Ok, the actual signalling of
errors will come later.

Its callers are changed to accommodate for the new return type and to
display errors as needed.

This is just a cosmetic (I hope) change; the nodes shouldn't be used
anyway, and we only correct the display message.

This patch drops compatiblity with Ganeti 1.2 and adds support for
offline nodes in the cluster. When reading from RAPI, the drained nodes
are considered offline so that we don't allocate on them too.