zaneb / image-customization-controller

Image customization controller for metal3 preprovisioningimage

Machine Image Customization Controller

This repo contains a controller that reconciles Metal³'s PreprovisioningImage custom resources. The image built is a CoreOS live image customized with an Ignition file to start the Ironic Python Agent (IPA) and containing any per-host network data provided in NMState format. Images are served from a webserver built in to the controller.

The main reconciler loop is vendored from the generic Metal³ implementation. Only a custom ImageProvider plugin is implemented here.

Image building

Network data for each host must be in NMState format, under a key named nmstate in the Secret specified by the networkDataName field in the PreprovisioningImage.

Note that all PreprovisioningImages with the label infraenvs.agent-install.openshift.io will be ignored by this controller.

Generated URLs are random and will change when the controller is restarted.

Only the Ignition file for each image is stored. When an HTTP request is received, the web server generates a stream on the fly with a CPIO archive containing the Ignition file overlaid on the appropriate portion of the ISO or appended to the initramfs. HTTP Range requests are supported.

How to run

Environment

The following environment variables are required:

• IRONIC_AGENT_IMAGE --- Pullspec for the IPA container image
• DEPLOY_ISO --- Filesystem path to the CoreOS base ISO
• DEPLOY_INITRD --- Filesystem path to the CoreOS initramfs

The following environment variables can also be set to customize the content of the Ignition:

• IRONIC_BASE_URL
• IRONIC_INSPECTOR_BASE_URL
• IRONIC_AGENT_PULL_SECRET
• IRONIC_RAMDISK_SSH_KEY
• REGISTRIES_CONF_PATH
• IP_OPTIONS
• HTTP_PROXY
• HTTPS_PROXY
• NO_PROXY

Running the Controller

The controller binary is /machine-image-customization-controller.

The following command line flags are used for configuration:

• -namespace --- Namespace that the controller watches to reconcile preprovisioningimage resources. (Defaults to $WATCH_NAMESPACE; if not set watches all namespaces.)
• -images-bind-addr --- The address and port for the web server to bind to. (Defaults to :8084.)
• -images-publish-addr --- The address clients would access the images endpoint from. (Defaults to http://127.0.0.1:8084.)

Running statically

There is also a separate binary, /machine-image-customization-server, that runs the web server using static config files, instead of as a Kubernetes controller.

The following command line flags are used for configuration:

• -nmstate-dir --- Location of static NMState files (named with the target image, e.g. worker-0.yaml).
• -images-bind-addr --- The address and port for the web server to bind to. (Defaults to :8084.)
• -images-publish-addr --- The address clients would access the images endpoint from. (Defaults to http://127.0.0.1:8084.)

An NMState file named <nmstate-dir>/worker-0.yaml will be built into images published at <images-publish-addr>/worker-0.iso and <images-publish-addr>/worker-0.initramfs.