Customize netlab

netlab is designed to be highly extensible and customizable. Starting with the system settings, you can:

Overwrite system defaults, either with user default files or in the lab topology.
Change the default device images to run a specific software version in your lab.
Change system addressing pools or define your own.

If you want to use netlab to deploy additional device configuration, you can:

Use netlab config to add custom configuration to an already-provisioned lab.
List your own configuration templates in node- or group config attribute to configure functionality not yet supported by netlab during netlab up or netlab initial process.
Define your own global-, node-, link- or interface attributes to parametrize your configurations.

You can also augment the netlab data model transformation or add new functionality with plugins.

If you want to change the provisioning or device configuration templates, you can:

Create your own device configuration templates: copy a system device configuration template into templates/module/device.j2 file[1] and modify it. You can have custom device configuration templates in the current directory or in the ~/.netlab directory.
Create your own device provisioning template: copy a system template into provider/device-domain.j2 file and modify it.

Tip

Use the ‌netlab create –debug paths command to display the components of individual search paths and the directories netlab uses when searching those paths (non-existent directories are removed from the search paths).

You can use the same command to troubleshoot template errors; the debugging printouts display every template file netlab searched for and the search path it used for the search.

Warning

The device provisioning templates can use only built-in Jinja2 filters and a subset of ‌ipaddr and ‌hwaddr filter functionality.

Finally, you might want to use external tools or devices not yet supported by netlab:

Adding external tools is relatively easy.
If you want to add unsupported devices to a lab but are willing to configure them manually, just define them as unknown devices.
Adding new functionality to an existing device or adding a new device to netlab takes more effort. When adding a new device, it’s easier to define a new device and keep it unprovisioned than going for a full-blown implementation.

Regardless of how far you’re willing to go, we’d appreciate if you decided to contribute your changes, but it’s perfectly fine to keep them private. The best part: you don’t have to modify the netlab package to get the job done; you could use user defaults to define new stuff, and user-defined configuration templates (see above) to configure it.