HCIDOCS-75: Add IPI installation workflow information to our documentation

Author: kdrake20

installing/installing_bare_metal/ipi/ipi-install-prerequisites.adoc

@@ -60,3 +60,5 @@ include::modules/ipi-install-out-of-band-management.adoc[leveloffset=+1]
 include::modules/ipi-install-required-data-for-installation.adoc[leveloffset=+1]
 
 include::modules/ipi-install-validation-checklist-for-nodes.adoc[leveloffset=+1]
+
+include::modules/ref_ipi-installation-overview.adoc[leveloffset=+1]

modules/ref_ipi-installation-overview.adoc

@@ -0,0 +1,52 @@
+// Module included in the following assemblies:
+//
+// * installing/installing_bare_metal/ipi/ipi-install-prerequisites.adoc
+
+:_mod-docs-content-type: REFERENCE
+
+[id="installation-overview_{context}"]
+= Installation overview
+
+The installation program supports interactive mode. However, you can prepare an `install-config.yaml` file containing the provisioning details for all of the bare-metal hosts, and the relevant cluster details, in advance.
+
+The installation program loads the `install-config.yaml` file and the administrator generates the manifests and verifies all prerequisites.
+
+The installation program performs the following tasks:
+
+* Enrolls all nodes in the cluster
+* Starts the bootstrap virtual machine (VM)
+* Starts the metal platform components as `systemd` services, which have the following containers:
+
+** Ironic-dnsmasq: The DHCP server responsible for handing over the IP addresses to the provisioning interface of various nodes on the provisioning network. Ironic-dnsmasq is only enabled when you deploy an {product-title} cluster with a provisioning network.
+** Ironic-httpd: The HTTP server that is used to ship the images to the nodes.
+** Image-customization
+** Ironic
+** Ironic-inspector (available in {product-title} 4.16 and earlier)
+** Ironic-ramdisk-logs
+** Extract-machine-os
+** Provisioning-interface
+** Metal3-baremetal-operator
+
+The nodes enter the validation phase, where each node moves to a _manageable_ state after Ironic validates the credentials to access the Baseboard Management Controller (BMC).
+
+When the node is in the manageable state, the _inspection_ phase starts. The inspection phase ensures that the hardware meets the minimum requirements needed for a successful deployment of {product-title}.
+
+The `install-config.yaml` file details the provisioning network. On the bootstrap VM, the installation program uses PXE to push a live image to every node with the Ironic Python Agent (IPA) loaded. When using virtual media, it connects directly to the BMC of each node to virtually attach the image.
+
+When using PXE boot, all nodes reboot to start the process:
+
+* The `ironic-dnsmasq` service running on the bootstrap VM provides the IP address of the node and the TFTP boot server.
+* The first-boot software loads the root file system over HTTP.
+* The `ironic` service on the bootstrap VM receives the hardware information from each node.
+
+The nodes enter the cleaning state, where each node must clean all the disks before continuing with the configuration.
+
+Once the cleaning state finishes, the nodes enter the available state and the installation program moves the nodes to the deploying state.
+
+IPA runs the `coreos-installer` command to install the {op-system-first} image on the disk defined by the `rootDeviceHints` parameter in the `install-config.yaml` file. The node boots by using {op-system}.
+
+After the installation program configures the control plane nodes, it moves control from the bootstrap VM to the control plane nodes and deletes the bootstrap VM.
+
+The Bare Metal Operator continues the deployment of the workers, storage, and infra nodes.
+
+After the installation completes, the nodes move to the active state. You can then proceed with postinstallation configuration and other Day 2 tasks.