baremetal: expand baremetal IPI docs to include customizations

The platform now has a bunch of optional possible customizations, this
expands the documentation to follow the other platforms by including a
customization.md that details each of the options and why you might want
to use them.

docs/user/customization.md

@@ -49,6 +49,7 @@ The following `install-config.yaml` properties are available:
         The default is 172.30.0.0/16.
 * `platform` (required object): The configuration for the specific platform upon which to perform the installation.
     * `aws` (optional object): [AWS-specific properties](aws/customization.md#cluster-scoped-properties).
+    * `baremetal` (optional object): [Baremetal IPI-specific properties](metal/customization_ipi.md).
     * `azure` (optional object): [Azure-specific properties](azure/customization.md#cluster-scoped-properties).
     * `openstack` (optional object): [OpenStack-specific properties](openstack/customization.md#cluster-scoped-properties).
     * `vsphere` (optional object): [vSphere-specific properties](vsphere/customization.md#cluster-scoped-properties).

docs/user/metal/customization_ipi.md

@@ -0,0 +1,85 @@
+# Bare Metal Platform Customization
+
+## Cluster-scoped properties
+
+### Image Overrides
+
+When doing a disconnected installation, the baremetal platform has the
+additional requirement that we have locations to download the RHCOS
+images. The installer downloads these from a location described in
+[/data/data/rhcos.json](/data/data/rhcos.json), but they can be
+overridden to point to a local mirror.
+
+The SHA256 parameter in the URLs are required, and should match the
+uncompressed SHA256 from rhcos.json.
+
+
+* `bootstrapOSImage` (optional string): Override the image used for the
+    bootstrap virtual machine.
+* `clusterOSIMAge` (optional string): Override the image used for
+    cluster machines.
+
+Example:
+
+```yaml
+platform:
+  baremetal:
+      bootstrapOSImage: http://mirror.example.com/images/rhcos-43.81.201912131630.0-qemu.x86_64.qcow2.gz?sha256=f40e826ac4a6c5c073416a7bc0039ec8726a338885d2031e7607cec8783e580e
+      clusterOSImage: http://mirror.example.com/images/rhcos-43.81.201912131630.0-openstack.x86_64.qcow2.gz?sha256=ffebbd68e8a1f2a245ca19522c16c86f67f9ac8e4e0c1f0a812b068b16f7265d
+```
+
+### Networking customization
+
+By default, the baremetal IPI environment uses a provisioning network of
+`172.22.0.0/24`, picks the 2nd and 3rd address of that subnet for the
+bootstrap and cluster provisioning IP's, and operates an internal DHCP
+and TFTP server in the cluster to support provisioning. Much of this can
+be customized.
+
+
+* `provisioningNetorkCIDR` (optional string): Override the default provisioning network.
+* `bootstrapProvisioningIP` (optional string): Override the bootstrap
+    provisioning IP. If unspecified, uses the 2nd address in the
+    provisioning network's subnet.
+* `provisioningHostIP` (optional string): Override the IP used by the
+    cluster's provisioning infrastructure. If unspecified, uses the 3rd
+    address in the provisioning network's subnet.
+
+Example:
+
+```yaml
+platform:
+  baremetal:
+    provisioningNetworkCIDR: 172.23.0.0/16
+    bootstrapProvisioningIP: 172.23.0.2
+    provisioningHostIP: 172.23.0.3
+```
+
+* `provisioningDHCPRange` (optional string): By default, the installer picks a range from
+  the 10th to 100th addresses. To use a different range, specify this
+  using the provisioingDHCPRange option in the baremetal platform. This
+  should be a comma-separated list indicating the start and end range.
+
+Example:
+
+```yaml
+platform:
+  baremetal:
+    provisioningDHCPRange: "172.23.0.10,172.23.0.100"
+```
+
+* `provisioningDHCPExternal` (optional boolean): If you would prefer to
+use an external DHCP server, you can specify provisioningDHCPExternal,
+in which case the cluster will only run TFTP.  When using PXE boot for
+the control plane and workers, your DHCP server needs to specify the
+next-server as `bootstrapProvisioningIP` for the control plane, and
+`provisioningHostIP` for the workers.
+
+Example:
+
+```yaml
+platform:
+  baremetal:
+    provisioningDHCPExternal: true
+```
+

docs/user/metal/install_ipi.md

@@ -89,7 +89,8 @@ containing all of the details of the bare metal hosts to be provisioned.
 
 The `install-config.yaml` file requires some additional details.  Most of the
 information is teaching the installer and the resulting cluster enough about
-the available hardware so that it is able to fully manage it.
+the available hardware so that it is able to fully manage it. There are
+[additional customizations](customization_ipi.md) possible.
 
 Here is an example `install-config.yaml` with the required `baremetal` platform
 details.