KaVLAN

See also: Introduction tutorial | Advanced Tutorial | KaVLAN | KaVLAN VPN

Overview

The goal of Kavlan is to allow people to manage VLAN on Grid'5000 nodes. The benefit is a complete level 2 isolation. It can be used together with OAR and Kadeploy to do some experimentations.

KaVLAN architecture

Installation status for all sites:

Sites	Version	Status
Grenoble	1.2.7-1
Lille	1.2.7-1
Luxembourg	1.2.7-1
Lyon	1.2.7-1
Nancy	1.2.7-1
Nantes	1.2.7-1
Rennes	1.2.7-1
Sophia	1.2.7-1
Toulouse	1.2.7-1
Strasbourg	1.2.7-1
Louvain	1.2.7-1

3 types of VLANs are available on Grid'5000:

• local VLANs (in green)
• routed VLANs (in blue)
• global VLANs (in purple)

1: Isolated VLAN

An isolated VLAN (also called local VLAN) is completely isolated from the rest of Grid'5000: no routing is configured. Therefore, you have to use a special host to reach your nodes inside this kind of VLAN. In that kind of VLAN, a DHCP server is brought up for you, so once you have put your nodes in it, you have to restart the networking service (with kaconsole3, or an 'at' command for instance), or reboot the node (with kareboot3). Then you will be able to reach any of your nodes within the VLAN using hostnames such as hostname-kavlan-VLAN_ID (adding the suffix -kavlan-VLAN_ID to the regular hostname), via the VLAN gateway: kavlan-VLAN-ID.

The figure below shows two jobs running with KaVLAN: each job has it's nodes isolated in a local VLAN (purple and green). The other nodes are all in the default VLAN (red). The only way to reach the isolated nodes is to use a gateway node (kavlan-1 and kavlan-2 in the figure). The gateway has two Ethernet interfaces: one in the default VLAN and one in the dedicated VLAN. This way, you can use ssh to reach your nodes. An other way to reach an isolated node is to use the kaconsole command.

KaVLAN architecture: 2 jobs running KaVLAN

	Note
	The gateways are NOT doing any routing: they are only used as ssh gateways.

	Note
	As your nodes are isolated from the rest of Grid'5000, NFS mounts of /home partition is not possible. Therefore, Grid'5000 environments that mount /home partition (-nfs, -big, -prod) may fail to boot

2: Routed VLAN

This kind of VLAN is not isolated at the layer 3. Therefore you can reach the nodes inside the VLAN from the rest of Grid5000. No need for an ssh gateway.

Nodes in the vlan are accessible with the hostname : hostname-kavlan-VLAN_ID (like in local vlan, but from the frontend for example)

3: Global VLAN

A global VLAN is a VLAN which is spread on all grid5000 sites (using IEEE 802.1ad encapsulation, also known as QinQ). Therefore you can configure nodes of different sites on the same VLAN (same layer 2 network) ! There will be no routing between these nodes. To reach nodes inside a VLAN, routing is configured on the router of the site where you reserved this global VLAN.

Usage

How to reserve a VLAN

KaVLAN only works with deploy reservations; to obtain nodes and a VLAN, you must reserve kavlan resources (VLAN-IDs) with the oarsub command. There are 3 kinds of resources defined in OAR: kavlan, kavlan-local, kavlan-global. For example, if you need 3 nodes and a local VLAN, you can run:

frontend:

oarsub -t deploy -l {"type='kavlan-local'"}/vlan=1+/nodes=3 -I

Then you can get the id of your VLAN using the kavlan command

frontend:

kavlan -V

If you run this command from outside the shell which is started by OAR for your reservation, you must give the OAR JOBID.

frontend:

kavlan -V -j JOBID

You should get an integer in the <1-3> range for local VLANs, <4-9> for routed vlan. For global VLANs, one VLAN_ID is available per site.

You can get all the options of the kavlan command using --help:

# kavlan --help
Usage: kavlan [options]
Specific options:
    -i, --vlan-id N                  set VLAN ID (integer or DEFAULT)
    -C, --ca-cert CA                 CA certificate
    -c, --client-cert CERT           client certificate
    -k, --client-key KEY             client key
    -l, --get-nodelist               Show nodenames in the given vlan
    -e, --enable-dhcp                Start DHCP server
    -d, --disable-dhcp               Stop DHCP server
    -V, --show-vlan-id               Show vlan id of job (needs -j JOBID)
    -g, --get-vlan                   Show vlan of nodes
    -s, --set-vlan                   Set vlan of nodes
    -j, --oar-jobid JOBID            OAR job id
    -m, --machine NODE               set nodename (several -m are OK)
    -f, --filename NODEFILE          read nodes from a file
    -u, --user USERNAME              username
    -v, --[no-]verbose               Run verbosely
    -q, --[no-]quiet                 Run quietly
        --[no-]debug                 Run with debug output
    -h, --help                       Show this message
        --version                    Show version

Once you have a kavlan reservation running, you can put your nodes in your VLAN (and later, back into the default VLAN) at anytime during the lifetime of your job. For local VLANs, you are also allowed to connect to the VLAN gateway, which is named kavlan-<ID> where ID is your VLAN ID,

To get more information on how to use a local VLAN, you can read the following tutorial: Network_isolation_on_Grid'5000#Change_the_VLAN_of_your_nodes_manually

If you want to learn how to use KaVLAN, you can try the tutorial on Network isolation on Grid'5000