install.rst: note about the default parameters

As we know, those are just defaults, mostly chosen by replicating the
only behavior we supported before allowing customization. They may need
changes, to work in specific environments (which is why we introduced
them in the first place).

This tries to address issue 83, which was caused by the default
parameters not being correct for the target cluster.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

diff --git a/doc/install.rst b/doc/install.rst
index f8a0221..1f5b442 100644 (file)
--- a/doc/install.rst
+++ b/doc/install.rst
@@ -549,6 +549,21 @@ pass ``--enabled-hypervisors=kvm`` to the init command.
 You can also invoke the command with the ``--help`` option in order to
 see all the possibilities.
 
+Hypervisor/Network/Cluster parameters
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Please note that the default hypervisor/network/cluster parameters may
+not be the correct one for your environment. Carefully check them, and
+change them at cluster init time, or later with ``gnt-cluster modify``.
+
+Your instance types, networking environment, hypervisor type and version
+may all affect what kind of parameters should be used on your cluster.
+
+For example kvm instances are by default configured to use a host
+kernel, and to be reached via serial console, which works nice for linux
+paravirtualized instances. If you want fully virtualized instances you
+may want to handle their kernel inside the instance, and to use VNC.
+
 Joining the nodes to the cluster
 ++++++++++++++++++++++++++++++++