X-Git-Url: https://code.grnet.gr/git/ganeti-local/blobdiff_plain/49148d15adb7b2e0694644c5307a17378c312e00..32708d0a16c33d758b31aed191a9596727073b87:/README diff --git a/README b/README index 62b9c1a..67d5d48 100644 --- a/README +++ b/README @@ -1,112 +1,8 @@ -Ganeti Cluster tools (ganeti-htools) -==================================== +Ganeti 2.6 +========== -These are some simple cluster tools for fixing common allocation -problems on Ganeti 2.0 clusters. +For installation instructions, read the INSTALL and the doc/install.rst +files. -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)``. - -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). - - -Integration with Ganeti ------------------------ - -The ``hbal`` and ``hspace`` programs can either get their input from -text files, locally from the master daemon (when run on the master node -of a cluster), or remote from a cluster via RAPI. The "-L" argument -enables local collection (with an optional path to the unix socket). For -online collection via RAPI, the "-m" argument should specify the cluster -or master node name. Only ``hbal`` and ``hspace`` use these arguments, -``hail`` uses the standard iallocator API and thus doesn't need any -special setup (just needs to be installed in the right directory). - -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, ``gnt-node list`` and ``gnt-instance list`` could be -used, and their output concatenated in a single file, separated by one -blank line. If you need to do this manually, you'll need to check the -sources to see which fields are needed exactly. - - -The ``hail`` program gets its data automatically from Ganeti when used -as described in its section. - -Installation ------------- - -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: - -- `json `_ -- `curl `_ -- `network `_ - -Once these are installed, just typing *make* in the top-level directory -should be enough. If you edit the documentation sources, you will need -the ``pandoc`` program to rebuilt it. - -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. - -.. vim: set textwidth=72 : -.. Local Variables: -.. mode: rst -.. fill-column: 72 -.. End: +For a brief introduction, read the ganeti(7) manpage and the other pages +it suggests.