Air-gapped Installation Guide#

Prerequisites#

In order to install HMC in an air-gapped environment, you need will need the following:

An installed k0s cluster that will be used as the management cluster. If you do not yet have a k0s cluster, you can follow the Airgapped Installation documentation. k0s is recommended for airgapped installations because it implements an OCI image bundle watcher which allows k0s to utilize a bundle of management cluster images easily. Any Kubernetes distribution can be used, but instructions for using k0s are provided here.
The KUBECONFIG of a management cluster that will be the target for the HMC installation.
A registry that is accessible from the airgapped hosts to store the HMC images. If you do not have a registry you can deploy a local Docker registry or use mindthegap
Warning

If using a local Docker registry, ensure the registry URL is added to the insecure-registries key within the Docker /etc/docker/daemon.json file.
```
{
  "insecure-registries": ["<registry-url>"]
}
```
A registry and associated chart repository for hosting HMC charts. At this time all HMC charts MUST be hosted in a single OCI chart repository. See Use OCI-based registries in the Helm documentation for more information.
jq, Helm and Docker binaries installed on the machine where the airgap-push.sh script will be run.

Installation#

Download the HMC airgap bundle, the bundle contains the following:
- images/hmc-images-<version>.tgz - The image bundle tarball for the management cluster, this bundle will be loaded into the management cluster.
- images/hmc-extension-images-<version>.tgz - The image bundle tarball for the managed clusters, this bundle will be pushed to a registry where the images can be accessed by the managed clusters.
- charts - Contains the HMC Helm chart, dependency charts and k0s extensions charts within the extensions directory. All of these charts will be pushed to a chart repository within a registry.
- scripts/airgap-push.sh - A script that will aid in re-tagging and pushing the ManagedCluster required charts and images to a desired registry.
Extract and use the airgap-push.sh script to push the extensions images and charts contents to the registry. Ensure you have logged into the registry using both docker login and helm registry login before running the script.
```
tar xvf hmc-airgap-<version>.tgz scripts/airgap-push.sh
./scripts/airgap-push.sh -r <registry> -c <chart-repo> -a hmc-airgap-<version>.tgz
```
Next, extract the management bundle tarball and sync the images to the k0s cluster which will host the management cluster. See Sync the Bundle File for more information.

Note

Multiple image bundles can be placed in the /var/lib/k0s/images directory for k0s to use and the existing k0s airgap bundle does not need to be merged into the hmc-images-<version>.tgz bundle.
```
tar -C /var/lib/k0s -xvf hmc-airgap-<version>.tgz "images/hmc-images-<version>.tgz"
```
Install the HMC Helm chart on the management cluster from the registry where the HMC charts were pushed. The HMC controller image is loaded as part of the airgap management bundle and does not need to be customized within the Helm chart, but the default chart repository configured via controller.defaultRegistryURL should be set to reference the repository where charts have been pushed.
```
helm install hmc oci://<chart-repository>/hmc \
  --version <hmc-version> \
  -n hmc-system \
  --create-namespace \
  --set controller.defaultRegistryURL="oci://<chart-repository>"
```
Within the spec: for your desired ManagedCluster object, specify the custom image registry and chart repository to be used (the registry and chart repository where the extensions bundle and charts were pushed).
```
spec:
 config:
   extensions:
    imageRepository: ${IMAGE_REPOSITORY}
    chartRepository: ${CHART_REPOSITORY}
```