Node can be added and removed (if they host no instances) at will from
the cluster. In a HA cluster and only with HA instances, the loss of any
single node will not cause disk data loss for any instance; of course,
-a node crash will cause the crash of the its primary instances.
+a node crash will cause the crash of its primary instances.
A node belonging to a cluster can be in one of the following roles at a
given time:
Depending on the role, each node will run a set of daemons:
-- the :command:`ganeti-noded` daemon, which control the manipulation of
+- the :command:`ganeti-noded` daemon, which controls the manipulation of
this node's hardware resources; it runs on all nodes which are in a
cluster
- the :command:`ganeti-confd` daemon (Ganeti 2.1+) which runs on all
Ganeti will start an instance with up to its maximum instance memory. If
not enough memory is available Ganeti will use all the available memory
-down to the instance minumum memory. If not even that amount of memory
+down to the instance minimum memory. If not even that amount of memory
is free Ganeti will refuse to start the instance.
Note, that this will not work when an instance is in a permanently
~~~~~~~~~~~~~~~~~~~~~~~~~~
If an instance is built in highly available mode, it currently runs and
-both its nodes are running fine, you can at migrate it over to its
+both its nodes are running fine, you can migrate it over to its
secondary node, without downtime. On the master node you need to run::
$ gnt-instance migrate %INSTANCE_NAME%
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It is important to note that for Ganeti to be able to do any disk
-operation, the Linux machines on top of which Ganeti must be consistent;
-for LVM, this means that the LVM commands must not return failures; it
-is common that after a complete disk failure, any LVM command aborts
-with an error similar to::
+operation, the Linux machines on top of which Ganeti runs must be
+consistent; for LVM, this means that the LVM commands must not return
+failures; it is common that after a complete disk failure, any LVM
+command aborts with an error similar to::
$ vgs
/dev/sdb1: read failed after 0 of 4096 at 0: Input/output error
$ gnt-instance recreate-disks %INSTANCE%
-Note that this will fail if the disks already exists.
+Note that this will fail if the disks already exists. The instance can
+be assigned to new nodes automatically by specifying an iallocator
+through the ``--iallocator`` option.
Conversion of an instance's disk type
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~