frezbo / extensions

Talos Linux System Extensions

Talos Linux System Extensions

This repo serves as a central place for publishing supported extensions to Talos Linux. Extensions allow for additional functionality on top of the default Talos Linux capabilities. Things like gVisor, GPU support, etc. are good candidates for extensions.

Using Extensions

Extensions in this repo are published as Docker images. These images can be specified in the Talos Linux machine configuration and, when present, will get extracted and laid down as part of the installation process. The image is composed of a manifest.yaml file that provides information and compatibility information, as well as a rootfs that contains things like compiled binaries that are bind mounted into the system.

Building Extensions

In the current form, building extensions requires the use of our bldr tool. It is highly recommended to take a look at an existing extensions as a template for building your own. The rough flow should look like the following:

• Create a manifest.yaml file that contains information about your system extension. See instructions below for this file.
• Create a pkg.yaml file that details the full flow of downloading, building, installing your application.
• Once you have these, add your extension to the TARGETS list in the Makefile.
• You can now build your extension using make like make <extension-name> PLATFORM=linux/amd64
• If you wish to output the contents of the image and validate your install, you can issue make local-<extension-name> PLATFORM=linux/amd64 DEST=_out. The contents will then be present in the _out directory.

Creating manifest.yaml

The manifest.yaml file should match the following format:

version: v1alpha1
metadata:
  name: <extension name>
  version: <version of the package the extension installs>-<version of the extensions repo (tracks with talos version)>
  author: Andrew Rynhard
  description: |
    <detailed description of the extension/package>
  ## The compatibility section is "optional" but highly recommended to specify a Talos version that
  ## has been tested and known working for this extension.
  compatibility:
    talos:
      version: ">= v1.0.0"

Creating pkg.yaml

Creating a pkg.yaml file is the normal process from bldr. See instructions here for details and examples on this format. Using other existing extensions in this repo for tips is also highly recommended. One important note is that the final directory tree of the generated package should look like this example from the gvisor package:

├── manifest.yaml
└── rootfs
    ├── etc
    │   └── cri
    │       └── conf.d
    │           └── gvisor.part
    └── usr
        └── local
            └── bin
                ├── containerd-shim-runsc-v1
                └── runsc

Note that the manifest.yaml file lives at the root, while all installed files live under /rootfs with the full tree of where they should live on the eventual Talos Linux install.

rootfs Restrictions

The following restrictions are applied to the contents of the rootfs of the system extension:

• no hardlinks
• no special files (FIFOs, devices, etc.)
• no world-writeable files or directories

Any paths in the rootfs should be contained within the following hierarchies:

• /etc/cri/conf.d/
• /lib/firmware/
• /usr/etc/udev/rules.d
• /usr/local/