Add `gnt-group assign-nodes` in the CLI

Signed-off-by: Adeodato Simo <dato@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

lib/client/gnt_group.py

@@ -50,6 +50,24 @@ def AddGroup(opts, args):
   SubmitOpCode(op, opts=opts)
 
 
+def AssignNodes(opts, args):
+  """Assign nodes to a group.
+
+  @param opts: the command line options selected by the user
+  @type args: list
+  @param args: args[0]: group to assign nodes to; args[1:]: nodes to assign
+  @rtype: int
+  @return: the desired exit code
+
+  """
+  group_name = args[0]
+  node_names = args[1:]
+
+  op = opcodes.OpAssignGroupNodes(group_name=group_name, nodes=node_names,
+                                  force=opts.force)
+  SubmitOpCode(op, opts=opts)
+
+
 def ListGroups(opts, args):
   """List node groups and their properties.
 
@@ -148,6 +166,9 @@ commands = {
   "add": (
     AddGroup, ARGS_ONE_GROUP, [DRY_RUN_OPT, ALLOC_POLICY_OPT, NODE_PARAMS_OPT],
     "<group_name>", "Add a new node group to the cluster"),
+  "assign-nodes": (
+    AssignNodes, ARGS_ONE_GROUP + ARGS_MANY_NODES, [DRY_RUN_OPT, FORCE_OPT],
+    "<group_name> <node>...", "Assign nodes to a group"),
   "list": (
     ListGroups, ARGS_MANY_GROUPS,
     [NOHDR_OPT, SEP_OPT, FIELDS_OPT],

man/gnt-group.rst

@@ -29,7 +29,7 @@ ADD
 | {*group*}
 
 Creates a new group with the given name. The node group will be
-initially empty.
+initially empty; to add nodes to it, use ``gnt-group assign-nodes``.
 
 The ``--node-parameters`` option allows you to set default node
 parameters for nodes in the group. Please see **ganeti**(7) for more
@@ -52,6 +52,21 @@ preferred
     (this is the default). Note that prioritization among groups in this
     state will be deferred to the iallocator plugin that's being used.
 
+ASSIGN-NODES
+~~~~~~~~~~~~
+
+| **assign-nodes**
+| [--force]
+| {*group*} {*node*...}
+
+Assigns one or more nodes to the specified group, moving them from their
+original group (or groups).
+
+By default, this command will refuse to proceed if the move would split
+between groups any instance that was not previously split (a split
+instance is an instance with a mirrored disk template, e.g. DRBD, that
+has the primary and secondary nodes in different node groups). You can
+force the operation with ``--force``.
 
 MODIFY
 ~~~~~~