Custom Images¶

RancherOS image can easily be remastered using a docker build. For example, to add cowsay to RancherOS you would use the following Dockerfile

Docker image¶

# The version of RancherOS to modify
FROM rancher/os2:v0.0.1-test01

# Your custom commands
RUN zypper install -y cowsay

# IMPORTANT: /usr/lib/rancheros-release is used for versioning/upgrade. The
# values here should reflect the tag of the image currently being built
ARG IMAGE_REPO=norepo
ARG IMAGE_TAG=latest
RUN echo "IMAGE_REPO=${IMAGE_REPO}"          > /usr/lib/rancheros-release && \
    echo "IMAGE_TAG=${IMAGE_TAG}"           >> /usr/lib/rancheros-release && \
    echo "IMAGE=${IMAGE_REPO}:${IMAGE_TAG}" >> /usr/lib/rancheros-release

And then the following commands

docker build --build-arg IMAGE_REPO=myrepo/custom-build \
             --build-arg IMAGE_TAG=v1.1.1 \
             -t myrepo/custom-build:v1.1.1 .
docker push myrepo/custom-build:v1.1.1

Your new customized OS is available at in the docker image myrepo/custom-build:v1.1.1 and you can check out your new image using docker with

docker run -it myrepo/custom-build:v1.1.1 bash

Bootable images¶

To create bootable images from the docker image you just created run the below command

# Download the ros-image-build script
curl -o ros-image-build https://raw.githubusercontent.com/rancher/os2/main/ros-image-build

# Run the script creating a qcow image, an ISO, and an AMI
bash ros-image-build myrepo/custom-build:v1.1.1 qcow,iso,ami

The above command will create an ISO, a qcow image, and publish AMIs. You need not create all three types and can change to comma seperated list to the types you care for.

Auto-installing ISO¶

To create an ISO that upon boot will automatically run an installation, as an alternative to iPXE install, run the following command.

bash ros-image-build myrepo/custom-build:v1.1.1 iso mycloud-config-file.txt

The third parameter is a path to a file that will be used as the cloud config passed to the installation. Refer to the installation and configuration reference for the contents of the file.