How to Add a Static DHCP Entry into Warewulf 4.5.x and 4.6.x
Introduction
This article will cover assigning an IP address via DHCP using Warewulf, to a device that is not managed directly by Warewulf itself. This is useful in instances where you want to assign an address to a Network Attached Storage (NAS) device or similar non-compute node.
The implementation can be done by modifying the included DHCP template that comes with Warewulf.
Resolution
First, backup the DHCP template (this is optional but recommended):
# For Warewulf 4.5.x
cp /var/lib/warewulf/overlays/host/rootfs/etc/dhcp/dhcpd.conf.ww /var/lib/warewulf/overlays/host/rootfs/etc/dhcp/dhcpd.conf.bak
# For Warewulf 4.6.x
cp /usr/share/warewulf/overlays/host/rootfs/etc/dhcp/dhcpd.conf.ww /usr/share/warewulf/overlays/host/rootfs/etc/dhcp/dhcpd.conf.ww.bak
There are two implementation methods available: adding the entries directly or creating a separate entry under /etc/dhcp/hosts.conf and including each host there. Both of these will be explained below.
Option 1 - Add entries directly
You'll add each individual entry directly to the dhcpd.conf file. You will use the following entry as an example:
host MyDevice {
hardware ethernet 00:11:22:33:44:55;
fixed-address 10.0.0.5;
}
Edit the following template file /var/lib/warewulf/overlays/host/rootfs/etc/dhcp/dhcpd.conf.ww for Warewulf 4.5.x using vi or the text editor of your choice.
Alternatively for Warewulf 4.6.x, edit this template file instead: /usr/share/warewulf/overlays/host/rootfs/etc/dhcp/dhcpd.conf.ww
At the bottom of the dhcpd.conf.ww file, we are looking for the line {{/* dhcp enabled */}}.
Move this under the {{- end}} line.
In between the {{/* dhcp enabled */}} and {{- end}} lines, add your host entry, similar to the example below:
...
{{end -}}{{/* range NetDevs */}}
{{end -}}{{/* range AllNodes */}}
{{end -}}{{/* if static */}}
{{- else}}
{{abort}}
{{- end}}
host MyDevice {
hardware ethernet 00:11:22:33:44:55;
fixed-address 10.0.0.5;
}
{{/* dhcp enabled */}}
Add as many hosts as required.
Run the wwctl configure dhcp command to update the DHCP config.
Verify your hosts were added correctly using cat /etc/dhcpd.conf.
Option 2 - Include a separate hosts file
Instead of adding each host to the template individually, you can also create a separate file and then include this in the main template.
Create a hosts.conf file under /etc/dhcp/.
Edit the hosts.conf file and add each individual host. Please see example host additions below:
host MyDevice {
hardware ethernet 00:11:22:33:44:55;
fixed-address 10.0.0.5;
}
host MyOtherDevice {
hardware ethernet AA:BB:CC:DD:EE:FF;
fixed-address 10.0.0.6;
}
Now edit the template.
Similar to "Option 1 - add entries directly", we are looking for the {{/* dhcp enabled */}} line in the file.
Move the {{/* dhcp enabled */}} line under the {{- end}} line.
In the middle of the {{/* dhcp enabled */}} and {{- end}} lines, add your host information.
Edit the dhcpd.conf.ww template file.
For Warewulf 4.5.x, this file is located under /var/lib/warewulf/overlays/host/rootfs/etc/dhcp/dhcpd.conf.ww.
For Warewulf 4.6.x, this file is found under /usr/share/warewulf/overlays/host/rootfs/etc/dhcp/dhcpd.conf.ww.
Exactly as before, you want to find the {{/* dhcp enabled */}} line.
Move this under the {{- end}} line.
Add your newly created hosts.conf via the Include line between the {{- end}} and {{/* dhcp enabled */}} lines. Below is an example:
...
{{end -}}{{/* range NetDevs */}}
{{end -}}{{/* range AllNodes */}}
{{end -}}{{/* if static */}}
{{- else}}
{{abort}}
{{- end}}
{{ Include "/etc/dhcp/hosts.conf" }}
{{/* dhcp enabled */}}
Again, run the wwctl configure dhcp command to update the DHCP config.
You can verify your hosts were added by checking the output of the cat /etc/dhcpd.conf command.
Conclusion
You have successfully assigned an IP address to a device via DHCP using Warewulf, therefore opening a world of possibilities to assign IPs to any device on your network; not just compute nodes. This shows just how flexible Warewulf is as a DHCP server, as well as for cluster management.