Fix a haddock/docstring issue

[ganeti-local] / README

diff --git a/README b/README
index 6949fbb..3e799c6 100644 (file)
--- a/README
+++ b/README
@@ -1,12 +1,44 @@
-Ganeti Cluster tools (htools)
-=============================
+Ganeti Cluster tools (ganeti-htools)
+====================================

 
 

-These are some simple cluster tools for fixing common problems. Right
-now N+1 and rebalancing are included.
+These are some simple cluster tools for fixing common allocation
+problems on Ganeti 2.0 clusters.

 
 

+Note that these tools are most useful for bigger cluster sizes
+(e.g. more than five or ten machines); at lower sizes, the
+computations they do can also be done manually.
+
+Most of the tools revolve around the concept of keeping the cluster
+N+1 compliant: this means that in case of failure of any node, the
+instances affected can be failed over (via ``gnt-node failover`` or
+``gnt-instance failover``) to their secondary node, and there is
+enough memory reserved for this operation without needing to shutdown
+other instances or rebalance the cluster.
+
+**Quick start** (see the installation section for more details):
+
+- (have the ghc compiler and the prerequisite libraries installed)
+- make
+- ./hbal -m $cluster -C -p
+- look at the original and final cluster layout, and if acceptable,
+  execute the given commands
+
+
+Available tools
+---------------
+
+Cluster rebalancer
+~~~~~~~~~~~~~~~~~~
+
+The rebalancer uses a simple algorithm to try to get the nodes of the
+cluster as equal as possible in their resource usage. It tries to
+repeatedly move each instance one step, so that the cluster score
+becomes better. We stop when no further move can improve the score.
+
+For algorithm details and usage, see the man page hbal(1).

 
 Cluster N+1 solver
 
 Cluster N+1 solver

-------------------
+~~~~~~~~~~~~~~~~~~

 
 This program runs a very simple brute force algorithm over the instance
 placement space in order to determine the shortest number of replace-disks
 
 This program runs a very simple brute force algorithm over the instance
 placement space in order to determine the shortest number of replace-disks

@@ -15,34 +47,53 @@ just one that passes N+1 checks.
 
 For algorithm details and usage, see the man page hn1(1).
 
 
 For algorithm details and usage, see the man page hn1(1).
 

-Cluster rebalancer
-------------------
+.. note:: This program is deprecated, hbal should be used instead.

 
 

-Compared to the N+1 solver, the rebalancer uses a very simple algorithm:
-repeatedly try to move each instance one step, so that the cluster score
-becomes better. We stop when no further move can improve the score.
+IAllocator plugin
+~~~~~~~~~~~~~~~~~
+
+The ``hail`` iallocator plugin can be used for allocations of mirrored
+and non-mirrored instances and for relocations of mirrored
+instances. It needs to be installed in Ganeti's iallocator search
+path—usually ``/usr/lib/ganeti/iallocators`` or
+``/usr/local/lib/ganeti/iallocators``, and after that it can be used
+via ganeti's ``--iallocator`` option (in various gnt-node/gnt-instance
+commands). See the man page hail(1) for more details.
+
+Cluster capacity estimator
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The ``hspace`` program will, given an input instance specification,
+estimate how many instances of those type can be place on the cluster
+before it will become full (as in any new allocation would fail N+1
+checks). For more details, see the man page hspace(1).

 
 

-For algorithm details and usage, see the man page hbal(1).

 
 Integration with Ganeti
 -----------------------
 
 
 Integration with Ganeti
 -----------------------
 

-The programs can either get their input from text files, or online
-from a cluster via RAPI. For online collection via RAPI, the "-m"
-argument to both hn1 and hbal should specify the cluster or master
-node name.
+The ``hbal``, ``hspace`` and ``hn1`` programs can either get their
+input from text files, or online from a cluster via RAPI. For online
+collection via RAPI, the "-m" argument to both hn1 and hbal should
+specify the cluster or master node name. ``hail`` uses the standard
+iallocator API and thus doesn't need any special setup (just needs to
+be installed in the right directory).

 
 

-For text files, a separate tool (hscan) is provided to automate their
-gathering if RAPI is available, which is better since it can extract
-more precise information. In case RAPI is not usable for whatever
-reason, the following two commands should be run::
+For generating the text files, a separate tool (``hscan``) is provided
+to automate their gathering if RAPI is available, which is better
+since it can extract more precise information. In case RAPI is not
+usable for whatever reason, the following two commands should be run::

 
 

-    gnt-node list -oname,mtotal,mnode,mfree,dtotal,dfree \
+    gnt-node list -oname,mtotal,mnode,mfree,dtotal,dfree,offline \

       --separator '|' --no-headers > nodes
       --separator '|' --no-headers > nodes

-    gnt-instance list -oname,admin_ram,sda_size,status,pnode,snodes \
+    gnt-instance list -oname,be/memory,sda_size,be/vcpus,status,pnode,snodes \

       --separator '|' --no-head > instances
 
       --separator '|' --no-head > instances
 

-These two files should be saved under the names of *nodes* and *instances*.
+These two files should be saved under the names of *nodes* and
+*instances*.
+
+The ``hail`` program gets its data automatically from Ganeti when used
+as described in its section.

 
 Installation
 ------------
 
 Installation
 ------------

@@ -51,11 +102,21 @@ If installing from source, you need a working ghc compiler (6.8 at
 least) and some extra Haskell libraries which usually need to be
 installed manually:
 
 least) and some extra Haskell libraries which usually need to be
 installed manually:
 

-- json
-- curl
+- json (http://hackage.haskell.org/cgi-bin/hackage-scripts/package/json)
+- curl (http://hackage.haskell.org/cgi-bin/hackage-scripts/package/curl)
+
+Once these are installed, just typing *make* in the top-level
+directory should be enough.

 
 

-One these are available, just typing *make* in the top-level directory
-should be enough.
+Only the ``hail`` program needs to be installed in a specific place,
+the other tools are not location-dependent.
+
+For running the (admittedly small) unittest suite (via *make check*),
+the QuickCheck version 1 library is needed.

 
 Internal (implementation) documentation is available in the ``apidoc``
 directory.
 
 Internal (implementation) documentation is available in the ``apidoc``
 directory.

+
+.. Local Variables:
+.. mode: rst
+.. End: