Synnefo

   Compute Service (codename: cyclades) <cyclades>

   Network Service (part of Cyclades) <networks>

.. _networks:

Network Service (part of Cyclades)

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Network setup overview

======================

Currently the Network Service is part of Cyclades and comes along with the

Cyclades software components.

Networking is deployment-specific and must be customized based on the specific

needs of the system administrator. However, to do so, the administrator needs

to understand how each level handles Virtual Networks, to be able to setup the

backend appropriately.

Network @ Cyclades level

------------------------

Cyclades understands two types of Virtual Networks:

a) One common Public Network (Internet)

b) One or more distinct Private Networks (L2)

a) When a new VM is created, it instantly gets connected to the Public Network

   (Internet). This means it gets a public IPv4 and IPv6 and has access to the

   public Internet.

b) Then each user, is able to create one or more Private Networks manually and

   add VMs inside those Private Networks. Private Networks provide Layer 2

   connectivity. All VMs inside a Private Network are completely isolated.

From the VM perspective, every Network corresponds to a distinct NIC. So, the

above are translated as follows:

a) Every newly created VM, needs at least one NIC. This NIC, connects the VM

   to the Public Network and thus should get a public IPv4 and IPv6.

b) For every Private Network, the VM gets a new NIC, which is added during the

   connection of the VM to the Private Network (without an IP). This NIC should

   have L2 connectivity with all other NICs connected to this Private Network.

To achieve the above, first of all, we need Network and IP Pool management support

at Ganeti level, for Cyclades to be able to issue the corresponding commands.

Network @ Ganeti level

----------------------

Currently, Ganeti does not support IP Pool management. However, we've been

actively in touch with the official Ganeti team, who are reviewing a relatively

big patchset that implements this functionality (you can find it at the

ganeti-devel mailing list). We hope that the functionality will be merged to

the Ganeti master branch soon and appear on Ganeti 2.7.

Furthermore, currently the `~okeanos service <http://okeanos.grnet.gr>`_ uses

the same patchset with slight differencies on top of Ganeti 2.4.5. Cyclades

0.9 are compatible with this old patchset and we do not guarantee that will

work with the updated patchset sent to ganeti-devel.

We do *NOT* recommend you to apply the patchset yourself on the current Ganeti

master, unless you are an experienced Cyclades and Ganeti integrator and you

really know what you are doing.

Instead, be a little patient and we hope that everything will work out of the

box, once the patchset makes it into the Ganeti master. When so, Cyclades will

get updated to become compatible with that Ganeti version.

Network @ Physical host level

-----------------------------

We talked about the two types of Network from the Cyclades perspective, from the

VMs perspective and from Ganeti's perspective. Finally, we need to talk about

the Networks from the physical (VM container) host's perspective.

If your version of Ganeti supports IP pool management, then you need to setup

your physical hosts for the two types of Networks. For the second type

(Private Networks), our reference installation uses a number of pre-provisioned

bridges (one for each Network), which are connected to the corresponding number

of pre-provisioned vlans on each physical host (node1 and node2). For the first

type (Public Network), our reference installation uses routing over one

preprovisioned vlan on each host (node1 and node2). It also uses the `NFDHCPD`

package for dynamically serving specific public IPs managed by Ganeti.

backend appropriately, before installing Cyclades. To do so, please read the

:ref:`Network <networks>` section before proceeding.