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universal-application-coreos-base

CoreOS pipeline for deploying immutable RHCOS systems for OpenShift and Kubernetes

CoreOS Base Pipeline

This pipeline facilitates the deployment of Red Hat CoreOS (RHCOS) systems, which serve as the foundation for OpenShift and Kubernetes cluster nodes. CoreOS provides an immutable infrastructure approach with atomic updates, container-optimized design, and enhanced security features.

Overview

When applied to a machine, this pipeline:

  1. Configures the machine to use the CoreOS workflow chain
  2. Sets up the proper bootenv for CoreOS installation
  3. Establishes the required parameters for CoreOS configuration
  4. Prepares the machine for ignition-based provisioning

Usage

This pipeline is typically applied as part of a higher-level cluster deployment, such as OpenShift, but can also be used independently to create CoreOS-based systems. It requires the following:

  • A properly configured DRP environment
  • The CoreOS content bundle installed
  • Access to Red Hat CoreOS (RHCOS) installation media

Workflow Chain

This pipeline overrides the standard workflow chain index to use coreos-install and remaps the workflow stages to follow the appropriate sequence for CoreOS installation:

universal-start → universal-pre-runbook
universal-burnin → universal-coreos-install
universal-discover → universal-hardware
universal-evaluate → universal-hardware
universal-hardware → universal-burnin
universal-maintenance → universal-discover
universal-rebuild → universal-discover
universal-coreos-install → universal-pre-runbook
universal-pre-runbook → universal-runbook
universal-runbook → universal-complete

Parameters

The following key parameters are set by this pipeline:

  • universal/application: Set to "coreos-base" to identify the application type
  • universal/workflow-chain-index-override: Set to "coreos-install" to use the CoreOS workflow
  • linux/install-bootenv-override: Set to "coreos-4-install" for the proper boot environment

This pipeline works with:

  • CoreOS ignition templates for system configuration
  • DRP agent integration for machine management
  • OpenShift deployment workflows when used as part of a cluster