NAME

makedhcp - Creates and updates DHCP configuration files.

SYNOPSIS

makedhcp -n [-l|--localonly]

makedhcp -a [-l|--localonly]

makedhcp -a -d [-l|--localonly]

makedhcp -d noderange [-l|--localonly]

makedhcp noderange [-s statements] [-l|--localonly]

makedhcp -q noderange

makedhcp [-h|--help]

DESCRIPTION

The makedhcp command creates and updates the DHCP configuration on the management node and service nodes. The makedhcp command is supported for both Linux and AIX clusters. On Linux, the DHCP implementation is selected by the site.dhcpbackend attribute. The auto setting keeps ISC DHCP on platforms where it is still available and uses Kea DHCP on platforms such as EL10 and Ubuntu 24.04.

  1. Start by filling out the networks(5) table properly.

  2. Then use the makedhcp -n option to create a new dhcp configuration file. You can set the site table, dhcplease attribute to the lease time for the dhcp client. The default value is 43200.

  3. Next, get the node IP addresses and MACs defined in the xCAT database. Also, get the hostnames and IP addresses pushed to /etc/hosts (using makehosts(8)) and to DNS (using makedns(8)).

  4. Then run makedhcp with a noderange or the -a option. This will inject DHCP configuration data pertinent to the specified nodes. With ISC DHCP, Linux node entries are updated through OMAPI. With Kea DHCP, node reservations are rendered into the Kea JSON configuration, validated, and the Kea service is restarted.

If you need to delete node entries from the DHCP configuration, use the -d flag.

OPTIONS

-n

Create a new dhcp configuration file with a network statement for each network the dhcp daemon should listen on. (Which networks dhcpd should listen on can be controlled by the dhcpinterfaces attribute in the site(5) table.) The makedhcp command will automatically restart the dhcp daemon after this operation. This option will replace any existing configuration file (making a backup of it first). For Linux systems using ISC DHCP, the file will include network entries as well as certain general parameters such as a dynamic range and omapi configuration. For Linux systems using Kea DHCP, the generated files are /etc/kea/kea-dhcp4.conf, /etc/kea/kea-dhcp6.conf when IPv6 networks are configured, and /etc/kea/kea-dhcp-ddns.conf when DDNS is enabled. For AIX systems the file will include network entries. On AIX systems, if there are any non-xCAT entries in the existing configuration file they will be preserved and added to the end of the new configuration file.

-a

Define all nodes to the DHCP server. (Will only add nodes that can be reached, network-wise, by this DHCP server.) The dhcp daemon does not have to be restarted after this. On AIX systems makedhcp will not add entries for cluster nodes that will be installed using NIM. The entries for these nodes will be managed by NIM.

noderange

Add the specified nodes to the DHCP server configuration.

-s statements

For the input noderange, the argument will be interpreted like dhcp configuration file text. This option is only supported by the ISC DHCP backend.

-d noderange

Delete node entries from the DHCP server configuration. On AIX, any entries created by NIM will not be removed.

-a -d

Delete all node entries, that were added by xCAT, from the DHCP server configuration.

-l|--localonly

Configure dhcpd on the local machine only. Without this option, makedhcp will also send this operation to any service nodes that service the nodes in the noderange.

-q noderange

Query the node entries from the DHCP server configuration. On AIX, any entries created by NIM will not be listed.

-h|--help

Display usage message.

RETURN VALUE

0. The command completed successfully.
1. An error has occurred.

EXAMPLES

1. Create a new DHCP configuration file and add the network definitions:
 makedhcp -n
2. Define all nodes to the dhcp server:
 makedhcp -a

Note: This does not add nodes that will be installed with AIX/NIM.

3. Will cause dhcp on the next request to set root-path appropriately for only node5. Note some characters (e.g. ") must be doubly escaped (once for the shell, and once for the OMAPI layer).
 makedhcp node5 -s 'option root-path  \"172.16.0.1:/install/freebsd6.2/x86_64\";'
4. Query a node from the DHCP server.
 # makedhcp -q node01
 node01: ip-address = 91.214.34.156, hardware-address = 00:00:c9:c6:6c:42

FILES

DHCP configuration files:

[AIX] /etc/dhcpsd.cnf

[SLES] /etc/dhcpd.conf

[RH] /etc/dhcp/dhcpd.conf

[Kea] /etc/kea/kea-dhcp4.conf

[Kea IPv6] /etc/kea/kea-dhcp6.conf

[Kea DDNS] /etc/kea/kea-dhcp-ddns.conf

SEE ALSO

noderange(3)