NixOS¶

Supported Releases¶

This chapter provides additional information for installing OMNeT++ on NixOS. The overall installation procedure is described in the Linux chapter.

The following NixOS releases are known to work:

• NixOS 25.11 or later

Installation Prerequisites¶

The omnetpp installation script (install.sh) can detect NixOS and install all the dependencies automatically. omnetpp assumes that certain features are enabled in your NixOS configuration. Make sure that nix.settings.experimental-features = [ "nix-command" "flakes" ]; is present in your NixOS configuration (/etc/nixos/configuration.nix).

Start the ./install.sh script in the root directory of the omnetpp installation and follow the instructions:

$ ./install.sh

After the script has finished, you can start an omnetpp session any time by typing:

# set up in the current shell
$ source setenv

# or within a new shell
$ ./setenv bash

Post-Installation Steps¶

Setting Up Debugging¶

By default, NixOS does not allow ptracing of non-child processes by non-root users. That is, if you want to be able to debug simulation processes by attaching to them with a debugger, or similarly, you want to be able to use OMNeT++ just-in-time debugging (debugger-attach-on-startup and debugger-attach-on-error configuration options), you need to explicitly enable them:

To temporarily allow ptracing non-child processes, enter the following command:

$ echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope

To permanently allow it, add

boot.kernel.sysctl."kernel.yama.ptrace_scope" = 0;

to the /etc/nixos/configuration.nix file and then rebuild your configuration.