Set attributes in the networks
table
Display the network settings defined in the xCAT
networks
table using:tabdump networks
#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:
[Recommended] Use
mkdef
to create/update an entry intonetworks
table.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
Use the
tabedit
command to modify the networks table directly in an editor:tabedit networks
Use the
makenetworks
command to automatically generate a entry in thenetworks
table:makenetworks
Verify the network statements
Domain and nameserver attributes must be configured in the
networks
table or in thesite
table 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
networks
table.The
dhcpinterfaces
keyword in thesite
table 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”, setdhcpinterfaces
using: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
dhcpinterfaces
using: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"
noboot
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
:noboot
indhcpinterfaces
using: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 makedhcp
command.
makedhcp -n