Customizing the Root Filesystem
The installer image contains
ONBUILD instructions that handle the following:
- the decompression, and unpacking of the
- the unsquashing of the rootfs
- the copying of new rootfs files
- the squashing of the new rootfs
- and the packing, and compression of the new
When used as a base image, the installer will perform the above steps automatically with the requirement that a
customization stage be defined in the
For example, say we have an image that contains the contents of a library we wish to add to the Talos rootfs.
We need to define a stage with the name
FROM scratch AS customization COPY --from=<name|index> <src> <dest>
Using a multi-stage
Dockerfile we can define the
customization stage and build
FROM the installer image:
FROM scratch AS customization COPY --from=<name|index> <src> <dest> FROM ghcr.io/talos-systems/installer:latest
When building the image, the
customization stage will automatically be copied into the rootfs.
customization stage is not limited to a single
In fact, you can do whatever you would like in this stage, but keep in mind that everything in
/ will be copied into the rootfs.
<dest>is the path relative to the rootfs that you wish to place the contents of
To build the image, run:
docker build --squash -t <organization>/installer:latest .
In the case that you need to perform some cleanup before adding additional files to the rootfs, you can specify the
RM build-time variable:
docker build --squash --build-arg RM="[<path> ...]" -t <organization>/installer:latest .
This will perform a
rm -rf on the specified paths relative to the rootfs.
RMmust be a whitespace delimited list.
The resulting image can be used to:
- generate an image for any of the supported providers
- perform bare-metall installs
- perform upgrades
We will step through common customizations in the remainder of this section.