Commit 9f83899a authored by Guido Trotter's avatar Guido Trotter

Install guide: talk about routing mode

The networking section is updated to talk about both routing and
bridging.
Signed-off-by: default avatarGuido Trotter <ultrotter@google.com>
Reviewed-by: default avatarIustin Pop <iustin@google.com>
parent 756d5ec3
......@@ -326,17 +326,36 @@ Configuring the network
**Mandatory** on all nodes.
Ganeti relies on Xen running in "bridge mode", which means the
instances network interfaces will be attached to a software bridge
running in dom0. Xen by default creates such a bridge at startup, but
your distribution might have a different way to do things.
You can run Ganeti either in "bridge mode" or in "routed mode". In bridge
mode, the default, the instances network interfaces will be attached to a
software bridge running in dom0. Xen by default creates such a bridge at
startup, but your distribution might have a different way to do things, and
you'll definitely need to manually set it up under KVM.
Beware that the default name Ganeti uses is ``xen-br0`` (which was
used in Xen 2.0) while Xen 3.0 uses ``xenbr0`` by default. The default
bridge your Ganeti cluster will use for new instances can be specified
at cluster initialization time.
.. admonition:: Debian
If you want to run in "routing mode" you need to specify that at cluster init
time (using the --nicparam option), and then no bridge will be needed. In
this mode instance traffic will be routed by dom0, instead of bridged.
In order to use "routing mode" under Xen, you'll need to change the relevant
parameters in the Xen config file. Under KVM instead, no config change is
necessary, but you still need to set up your network interfaces correctly.
By default, under KVM, the "link" parameter you specify per-nic will
represent, if non-empty, a different routing table name or number to use for
your instances. This allows insulation between different instance groups,
and different routing policies between node traffic and instance traffic.
You will need to configure your routing table basic routes and rules outside
of ganeti. The vif scripts will only add /32 routes to your instances,
through their interface, in the table you specified (under KVM, and in the
main table under Xen).
.. admonition:: Bridging under Debian
The recommended way to configure the Xen bridge is to edit your
``/etc/network/interfaces`` file and substitute your normal
......@@ -493,6 +512,9 @@ that the hostname used for this must resolve to an IP address reserved
**exclusively** for this purpose, and cannot be the name of the first
(master) node.
If you want to use a bridge which is not ``xen-br0``, or no bridge at all, use
the --nicparams
If the bridge name you are using is not ``xen-br0``, use the *-b
<BRIDGENAME>* option to specify the bridge name. In this case, you
should also use the *--master-netdev <BRIDGENAME>* option with the
......
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