Update docs for pci passthrough and host aggregate (#433)

* Adds docs to add new node to cluster

Adding docs to add new node(s) to the cluster.

* Update docs for pci passthrough and host aggregate

docs/adding-new-node.md

@@ -75,3 +75,14 @@ labels and annotations.
 ```
 
 At this point the compute node should be up and running and your `openstack` cli command should list the compute node under hosts.
+
+## For PCI passthrough
+
+If you are adding a new node to be a PCI passthrough compute, say for exposing GPU to the vm, at this stage you will have to
+setup your PCI Passthrough configuration. Follow steps from:  [Configuring PCI Passthrough in OpenStack](openstack-pci-passthrough.md)
+
+Once the PCI setup is complete follow the instructions from: [Adding Host Aggregates](openstack-host-aggregates.md) to setup host
+aggregates for the group of PCI devices. This helps us control the image/flavor/tennant build restriction on a given aggregate to
+better use underlying GPU resources.
+
+Once the host aggregate is setup follow the instructions from: [Genestack flavor documentation](openstack-flavors.md) to setup the right flavor.

docs/openstack-pci-passthrough.md

@@ -138,6 +138,8 @@ With the same `lspci` information used in the `vfio` setup, create a `device_spe
 {"vendor_id": "10de", "product_id": "1c30", "device_type": "type-PCI", "name": "p2000"}
 ```
 
+If you are configuring a PCI passthrough for say a GPU compute follow the instruction in the Node Overrides Explanation section of the service override documentation.
+
 1. See the [Genestack service override documentation](openstack-service-overrides.md) on how update your compute infrastructure to use the `device_spec` and `alias`.
 
 1. Create a custom flavor which has your alias name as a property. See the [Genestack flavor documentation](openstack-flavors.md) on how to craft custom flavors.