gnt-* {add,list,remove}-tags: Unify options

[ganeti-local] / man / hail.rst

diff --git a/man/hail.rst b/man/hail.rst
index c4f7fb7..925fc44 100644 (file)
--- a/man/hail.rst
+++ b/man/hail.rst
@@ -9,16 +9,15 @@ hail - Ganeti IAllocator plugin
 SYNOPSIS
 --------
 
-**hail** [ **-t** *datafile* | **--simulate** *spec* ] *input-file*
+**hail** [ **-t** *file* | **--simulate** *spec* ] [options...] *input-file*
 
 **hail** --version
 
 DESCRIPTION
 -----------
 
-hail is a Ganeti IAllocator plugin that allows automatic instance
-placement and automatic instance secondary node replacement using the
-same algorithm as **hbal**(1).
+hail is a Ganeti IAllocator plugin that implements the instance
+placement and movement using the same algorithm as **hbal**(1).
 
 The program takes input via a JSON-file containing current cluster
 state and the request details, and output (on stdout) a JSON-formatted
@@ -30,10 +29,6 @@ ALGORITHM
 
 The program uses a simplified version of the hbal algorithm.
 
-For relocations, we try to change the secondary node of the instance
-to all the valid other nodes; the node which results in the best
-cluster score is chosen.
-
 For single-node allocations (non-mirrored instances), again we
 select the node which, when chosen as the primary node, gives the best
 score.
@@ -42,11 +37,25 @@ For dual-node allocations (mirrored instances), we chose the best
 pair; this is the only choice where the algorithm is non-trivial
 with regard to cluster size.
 
-For node evacuations (*multi-evacuate* mode), we iterate over all
-instances which live as secondaries on those nodes and try to relocate
-them using the single-instance relocation algorithm.
+For relocations, we try to change the secondary node of the instance to
+all the valid other nodes; the node which results in the best cluster
+score is chosen.
+
+For node changes (*change-node* mode), we currently support DRBD
+instances only, and all three modes (primary changes, secondary changes
+and all node changes).
+
+For group moves (*change-group* mode), again only DRBD is supported, and
+we compute the correct sequence that will result in a group change; job
+failure mid-way will result in a split instance. The choice of node(s)
+on the target group is based on the group score, and the choice of group
+is based on the same algorithm as allocations (group with lowest score
+after placement).
+
+The deprecated *multi-evacuate* modes is no longer supported.
 
-In all cases, the cluster scoring is identical to the hbal algorithm.
+In all cases, the cluster (or group) scoring is identical to the hbal
+algorithm.
 
 OPTIONS
 -------
@@ -54,10 +63,9 @@ OPTIONS
 The options that can be passed to the program are as follows:
 
 -p, --print-nodes
-  Prints the before and after node status, in a format designed to
-  allow the user to understand the node's most important
-  parameters. See the man page **hbal**(1) for more details about this
-  field.
+  Prints the before and after node status, in a format designed to allow
+  the user to understand the node's most important parameters. See the
+  man page **htools**(1) for more details about this option.
 
 -t *datafile*, --text-data=*datafile*
   The name of the file holding cluster information, to override the
@@ -68,6 +76,18 @@ The options that can be passed to the program are as follows:
   data with a simulated cluster. For details about the description,
   see the man page **hspace**(1).
 
+-S *filename*, --save-cluster=*filename*
+  If given, the state of the cluster before and the iallocator run is
+  saved to a file named *filename.pre-ialloc*, respectively
+  *filename.post-ialloc*. This allows re-feeding the cluster state to
+  any of the htools utilities.
+
+-v
+  This option increases verbosity and can be used for debugging in order
+  to understand how the IAllocator request is parsed; it can be passed
+  multiple times for successively more information.
+
+
 CONFIGURATION
 -------------