Do you nohup?
When I’m testing a new build of the Kea DHCP server — especially one I compiled myself — I don’t always bother writing a systemd service right away. Sometimes I just want to launch it, throw traffic at it, watch the logs, and iterate on the config.
Here’s the simple way I do that:
nohup kea-dhcp4 -c /usr/local/etc/kea/kea-dhcp4.conf &
What’s Happening Here?
Let’s break it down:
nohup
Tells Linux: If I close this terminal, don’t kill this process.
Without nohup, when I close my SSH session or terminal window, the DHCP server would stop.
kea-dhcp4 -c /usr/local/etc/kea/kea-dhcp4.conf
This runs Kea’s DHCPv4 server, using the specified config file.
&
The ampersand says: Run this in the background.
So I get my shell prompt back and can do other things.
Why Run It This Way?
Normally, on a production server, you’d want this running as a service — managed by systemd — so that it starts on boot, restarts on failure, and logs cleanly.
But when testing:
- The binary may not be packaged as a service yet
- You may be tweaking the config constantly
- You may want to kill/restart it quickly without writing a service file
That’s when nohup ... & is a handy shortcut.
Where Do the Logs Go?
When you launch it like this, Linux will tell you:
nohup: ignoring input and appending output to 'nohup.out'
That means:
- The server’s output (logs, errors, status) will go to a file called
nohup.outin your current directory. - You can check this at any time:
tail -f nohup.out
When Should You NOT Do This?
This is not how you should run a production service, because:
- It won’t auto-restart if the server crashes
- It won’t start on boot
- The log file will grow forever if you don’t manage it
What I’m Doing Here
In this case, I’m testing a custom-compiled version of Kea-DHCP4. The systemd service isn’t written yet — that’ll come later in the project. For now, I just need to bring the server up so I can test my config and watch how it behaves under simulated load. This method gets me there quickly without a lot of extra setup.
--Create Wild Things
-Bryan