---
layout: docs
page_title: Network Plugins
description: Learn how Nomad manages custom user-specified network configurations.
---

# Network plugins

Nomad has built-in support for scheduling compute resources such as
CPU, memory, and networking. Nomad's network plugin support extends
this to allow scheduling tasks with purpose-created or specialty network
configurations. Network plugins are third-party plugins that conform to the
[Container Network Interface (CNI)][cni_spec] specification.

Network plugins need to be installed and configured on each client. The [Nomad
installation instructions][nomad_install] recommend installing the [CNI
reference plugins][cni_ref] because certain Nomad networking features, like
`bridge` network mode and Consul service mesh, leverage them to provide an
operating-system agnostic interface to configure workload networking.

Custom networking in Nomad is accomplished with a combination of CNI plugin
binaries and CNI configuration files.

## CNI plugins

Spec-compliant plugins should work with Nomad, however, it's possible a plugin
vendor has implemented their plugin to make non-standard API calls, or it is
otherwise non-compliant with the CNI specification. In those situations the
plugin may not function correctly in a Nomad environment. You should verify
plugin compatibility with Nomad before deploying in production.

CNI plugins are installed and configured on a per-client basis. Nomad consults
the path given in the client's [`cni_path`][] to find CNI plugin executables.

## CNI configuration files

CNI defines a network configuration format for administrators. It contains
directives for both the orchestrator and the plugins to consume.
At plugin execution time, this configuration format is interpreted by the
runtime and transformed in to a form to be passed to the plugins.

Nomad reads the following extensions from the [`cni_config_dir`][]—
`/opt/cni/config` by default:

* `.conflist` files are loaded as [network
  configurations][cni_spec_net_config] that contain a list of plugin
  configurations.

* `.conf` and `.json` files are loaded as individual [plugin
  configurations][cni_spec_plugin_config] for a specific network.

## Further reading

You can read more about how Nomad uses CNI plugins in the [CNI section of the
Nomad Networking documentation](/nomad/docs/networking/cni).

[3rd_party_cni]: https://www.cni.dev/docs/#3rd-party-plugins
[`cni_config_dir`]: /nomad/docs/configuration/client#cni_config_dir
[`cni_path`]: /nomad/docs/configuration/client#cni_path
[cni_ref]: https://github.com/containernetworking/plugins
[cni_spec]: https://www.cni.dev/docs/spec/
[cni_spec_net_config]: https://github.com/containernetworking/cni/blob/main/SPEC.md#configuration-format
[cni_spec_plugin_config]: https://github.com/containernetworking/cni/blob/main/SPEC.md#plugin-configuration-objects
[nomad_install]: /nomad/tutorials/get-started/get-started-install#post-installation-steps
