5.4. Configuring Additional Ethernet Interfaces

For compute nodes, Rocks uses the first ethernet interface (eth0) for management (e.g., reinstallation), monitoring (e.g., Ganglia) and message passing (e.g., OpenMPI over ethernet). Often, compute nodes have more than one ethernet interface. This procedure describes how to configure them.

Additional ethernet interfaces are configured from the frontend via the Rocks command line. It modifies entries in the networks table on the frontend to add information about an extra interface on a node.

Once you have the information in the networks table, every time you reinstall, the additional NIC will be configured.

Suppose you have a compute node with one configured network (eth0) and one unconfigured network (eth1):

# rocks list host interface compute-0-0
SUBNET  IFACE MAC               IP           NETMASK     MODULE NAME        VLAN
private eth0  00:1e:4f:b0:74:ef 10.1.255.254 255.255.0.0 tg3    compute-0-0 ------
------- eth1  00:10:18:31:74:43 ------------ ----------- tg3    ----------- ------

We'll configure eth1 with the following network info and associate eth1 with the public subnet:

• Name = fast-0-0

• IP address = 192.168.1.1

# rocks set host interface ip compute-0-0 eth1 192.168.1.1
# rocks set host interface name compute-0-0 eth1 fast-0-0     

Now we'll create a new 'network' and associate it with the new interface:

# rocks add network fast 192.168.1.0 255.255.255.0

And then we'll check our work:

# rocks list network
NETWORK  SUBNET        NETMASK       MTU  
private: 10.1.0.0      255.255.0.0   1500 
public:  137.110.119.0 255.255.255.0 1500 
fast:    192.168.1.0   255.255.255.0 1500

Now associate the new network to eth1.

# rocks set host interface subnet compute-0-0 eth1 fast

The interface eth1 is now configured:

# rocks list host interface compute-0-0
SUBNET  IFACE MAC               IP           NETMASK       MODULE NAME        VLAN
private eth0  00:1e:4f:b0:74:ef 10.1.255.254 255.255.0.0   tg3    compute-0-0 ------
fast    eth1  00:10:18:31:74:43 192.168.1.1  255.255.255.0 tg3    fast-0-0    ------

After specifying new network settings to a compute-0-0, execute the following command to apply the settings:

# rocks sync config
# rocks sync host network compute-0-0

If you configuring the interface to another public network, you can set the gateway for the interface with the rocks add host route command. For example, to set the route for the 192.168.1.0 network to 192.168.1.254 for compute-0-0, you'd execute: # rocks add host route compute-0-0 192.168.1.0 192.168.1.254 netmask=255.255.255.0