3.4. 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., MPICH 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-1-1 
SUBNET  IFACE MAC               IP             NETMASK   GATEWAY MODULE NAME
private eth0  00:0e:0c:5d:7e:5e 10.255.255.251 255.0.0.0 ------- e1000  compute-1-1
------- eth1  00:30:1b:b2:ea:61 -------------- --------- ------- tg3    -----------

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

• IP address = 192.168.1.1

• Gateway = 192.168.1.254

• Name = fast-1-1

# rocks set host interface ip compute-1-1 eth1 192.168.1.1
# rocks set host interface gateway compute-1-1 eth1 192.168.1.254
# rocks set host interface name compute-1-1 eth1 fast-1-1     
# rocks set host interface subnet compute-1-1 eth1 public       

The interface eth1 is now configured:

# rocks list host interface compute-1-1
SUBNET  IFACE MAC               IP             NETMASK       GATEWAY       MODULE NAME       
private eth0  00:0e:0c:5d:7e:5e 10.255.255.251 255.0.0.0     ------------- e1000  compute-1-1
public  eth1  00:30:1b:b2:ea:61 192.168.1.1    255.255.255.0 192.168.1.254 tg3    fast-1-1 

After specifying new network settings to a node, you will need to reinstall the node in order for the changes to take effect.