Set attributes in the
Display the network settings defined in the xCAT
#netname,net,mask,mgtifname,gateway,dhcpserver,tftpserver,nameservers,ntpservers,logservers, dynamicrange,staticrange,staticrangeincrement,nodehostname,ddnsdomain,vlanid,domain,mtu, comments,disable "10_0_0_0-255_0_0_0","10.0.0.0","255.0.0.0","eth0","10.0.0.101",,"10.4.27.5",,,,,,,,,,,,,
A default network is created for the detected primary network using the same netmask and gateway. There may be additional network entries in the table for each network present on the management node where xCAT is installed.
To define additional networks, use one of the following options:
mkdefto create/update an entry into
To create a network entry for 192.168.X.X/16 with a gateway of 192.168.1.254:
mkdef -t network -o net1 net=192.168.0.0 mask=255.255.0.0 gateway=192.168.1.254
tabeditcommand to modify the networks table directly in an editor:
makenetworkscommand to automatically generate a entry in the
Verify the network statements
Domain and nameserver attributes must be configured in the
networkstable or in the
sitetable for xCAT to function properly.
Initialize DHCP services¶
Configure DHCP to listen on different network interfaces [Optional]
The default behavior of xCAT is to configure DHCP to listen on all interfaces defined in the
dhcpinterfaceskeyword in the
sitetable allows administrators to limit the interfaces that DHCP will listen over. If the management node has 4 interfaces, (eth0, eth1, eth2, and eth3), and you want DHCP to listen only on “eth1” and “eth3”, set
dhcpinterfacesusing:chdef -t site dhcpinterfaces="eth1,eth3"
To set “eth1” and “eth3” on the management node and “bond0” on all nodes in the nodegroup=”service”, set
dhcpinterfacesusing:chdef -t site dhcpinterfaces="eth1,eth3;service|bond0"
or, to explicitly identify the management node with hostname
xcatmn:chdef -t site dhcpinterfaces="xcatmn|eth1,eth3;service|bond0"
For the IBM OpenPOWER S822LC for HPC (“Minsky”) nodes, the BMC and compute “eth0” share the left-side integrated ethernet port and compute “eth1” is the right-side integrated ethernet port. For these servers, it is recommended to use two physical cables allowing the BMC port to be dedicated and “eth1” used by the OS. When an open range is configured on the two networks, the xCAT Genesis kernel will be sent to the BMC interface and causes problems during hardware discovery. To support this scenario, on the xCAT management node, if “eth1” is connected to the BMC network and “eth3” is connected to the compute network, disable genesis boot for the BMC network by setting
dhcpinterfacesusing:chdef -t site dhcpinterfaces="eth1:noboot,eth3" # run the mknb command to remove the genesis # configuration file for the specified network mknb ppc64
For more information, see
dhcpinterfaces keyword in the site table.
After making any DHCP changes, create a new DHCP configuration file with the networks defined using the