50 Prepare downstream cluster image for air-gap scenarios #

The downstream-cluster-airgap-config.yaml file is the main configuration file for the downstream cluster image and the content has been described in the previous section (Section 49.2.5, “Additional configuration for Telco workloads”).

Currently, a custom script (custom/scripts/01-fix-growfs.sh) is required to grow the file system to match the disk size on first-boot after provisioning. The 01-fix-growfs.sh script contains the following information:

#!/bin/bash
growfs() {
  mnt="$1"
  dev="$(findmnt --fstab --target ${mnt} --evaluate --real --output SOURCE --noheadings)"
  # /dev/sda3 -> /dev/sda, /dev/nvme0n1p3 -> /dev/nvme0n1
  parent_dev="/dev/$(lsblk --nodeps -rno PKNAME "${dev}")"
  # Last number in the device name: /dev/nvme0n1p42 -> 42
  partnum="$(echo "${dev}" | sed 's/^.*[^0-9]\([0-9]\+\)$/\1/')"
  ret=0
  growpart "$parent_dev" "$partnum" || ret=$?
  [ $ret -eq 0 ] || [ $ret -eq 1 ] || exit 1
  /usr/lib/systemd/systemd-growfs "$mnt"
}
growfs /

The following script (custom/scripts/02-airgap.sh) is required to copy the images to the right place during the image creation process:

#!/bin/bash

# create the folder to extract the artifacts there
mkdir -p /opt/rke2-artifacts
mkdir -p /var/lib/rancher/rke2/agent/images

# copy the artifacts
cp install.sh /opt/
cp rke2-images*.tar.zst rke2.linux-amd64.tar.gz sha256sum-amd64.txt /opt/rke2-artifacts/

The following optional script (custom/scripts/03-performance.sh) can be used to configure the system for performance tuning:

#!/bin/bash

# create the folder to extract the artifacts there
mkdir -p /opt/performance-settings

# copy the artifacts
cp performance-settings.sh /opt/performance-settings/

The content of custom/files/performance-settings.sh is a script that can be used to configure the system for performance tuning and can be downloaded from the following link.

The following optional script (custom/scripts/04-sriov.sh) can be used to configure the system for SR-IOV:

#!/bin/bash

# create the folder to extract the artifacts there
mkdir -p /opt/sriov
# copy the artifacts
cp sriov-auto-filler.sh /opt/sriov/sriov-auto-filler.sh

The content of custom/files/sriov-auto-filler.sh is a script that can be used to configure the system for SR-IOV and can be downloaded from the following link.

As described for the non-airgap scenario in section (Section 49.2.7, “Telco required kernel modules”).

The following steps are required to prepare the air-gap artifacts using the release container image in order to populate a registry with the specific version artifacts. It handles RKE2 tarball generation, Helm chart OCI mirroring, and container image mirroring in a single command — no separate scripts are needed.

Note

The release container image already bundles /release_manifest.yaml and /release_images.yaml internally, so no additional manifest files need to be provided. For full flag reference and advanced usage, see the seactl documentation.