Merge "Document DCN deployment"

doc/source/install/advanced_deployment/distributed_compute_node.rst

@@ -0,0 +1,120 @@
+.. _distributed_compute_node:
+
+Distributed Compute Node deployment
+===================================
+
+Introduction
+------------
+Additional groups of compute nodes can be deployed and integrated with an
+existing deployment of a control plane stack. These compute nodes are deployed
+in separate stacks from the main control plane (overcloud) stack, and they
+consume some of the stack outputs from the overcloud stack to reuse as
+configuration data.
+
+Deploying these additional nodes in separate stacks provides for separation of
+management between the control plane stack and the stacks for additional compute
+nodes. The stacks can be managed, scaled, and updated separately.
+
+Using separate stacks also creates smaller failure domains as there are less
+baremetal nodes in each invidiual stack. A failure in one baremetal node only
+requires that management operations to address that failure need only affect
+the single stack that contains the failed node.
+
+A routed spine and leaf networking layout can be used to deploy these
+additional groups of compute nodes in a distributed nature. Not all nodes need
+to be co-located at the same physical location or datacenter. See
+:ref:`routed_spine_leaf_network` for more details.
+
+Such an architecture is referred to as "Distributed Compute Node" or "DCN" for
+short.
+
+
+Deploying from a centralized undercloud
+---------------------------------------
+The main overcloud control plane stack should be deployed as needed for the
+desired cloud architecture layout. This stack contains nodes running the
+control plane and infrastructure services needed for the cloud. For the
+purposes of this documentation, this stack is referred to as the overcloud
+stack.
+
+The overcloud stack may or may not contain compute nodes. It may be a user
+requirement that compute services are available within the overcloud stack,
+however it is not strictly required.
+
+Undercloud configuration
+^^^^^^^^^^^^^^^^^^^^^^^^
+TODO
+
+Saving configuration from the overcloud
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Once the overcloud has been deployed, data needs to be retrieved
+from the overcloud Heat stack and plan to pass as input values into the
+separate DCN deployment.
+
+Extract the needed data from the stack outputs:
+
+.. code-block:: bash
+
+  # EndpointMap: Cloud service to URL mapping
+  openstack stack output show standalone EndpointMap --format json \
+    | jq '{"parameter_defaults": {"EndpointMapOverride": .output_value}}' \
+    > endpoint-map.json
+
+  # AllNodesConfig: Node specific hieradata (hostnames, etc) set on all nodes
+  openstack stack output show standalone AllNodesConfig --format json \
+    | jq '{"parameter_defaults": {"AllNodesExtraMapData": .output_value}}' \
+    > all-nodes-extra-map-data.json
+
+  # GlobalConfig: Service specific hieradata set on all nodes
+  openstack stack output show $STACK GlobalConfig --format json \
+    | jq '{"parameter_defaults": {"GlobalConfigExtraMapData": .output_value}}' \
+    > $DIR/global-config-extra-map-data.json
+
+  # HostsEntry: Entries for /etc/hosts set on all nodes
+  openstack stack output show standalone HostsEntry -f json \
+    | jq -r '{"parameter_defaults":{"ExtraHostFileEntries": .output_value}}' \
+    > extra-host-file-entries.json
+
+The same passwords and secrets should be reused when deploying the additional
+compute stacks. These values can be saved from the existing control plane stack
+deployment with the following command::
+
+.. code-block:: bash
+
+  openstack object save overcloud plan-environment.yaml
+  python -c "import yaml; data=yaml.safe_load(open('plan-environment.yaml').read()); print yaml.dump(dict(parameter_defaults=data['passwords']))" > passwords.yaml
+
+Use the passwords.yaml enviornment file generated by the previous command, or
+reuse the environment file used to set the values for the control plane stack.
+
+.. note::
+
+  The `passwords.yaml` generated in the previous command contains sensitive
+  security data such as passwords and TLS certificates that are used in the
+  overcloud deployment.
+
+  Care should be taken to keep the file as secured as possible.
+
+Create an environment file for setting necessary oslo messaging configuration
+overrides:
+
+.. code-block:: bash
+
+  parameter_defaults:
+    ComputeExtraConfig:
+      oslo_messaging_notify_use_ssl: false
+      oslo_messaging_rpc_use_ssl: false
+
+
+Reusing networks from the overcloud
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+TODO
+
+Spine and Leaf configuration
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+TODO
+
+
+Standalone deployment
+---------------------
+TODO

doc/source/install/advanced_deployment/features.rst

@@ -32,4 +32,5 @@ Documentation on how to enable and configure various features available in
    designate
    multiple_overclouds
    tuned
+   distributed_compute_node
    deploy_openshift

doc/source/install/advanced_deployment/routed_spine_leaf_network.rst

@@ -1,3 +1,5 @@
+.. _routed_spine_leaf_network:
+
 Deploying Overcloud with L3 routed networking
 =============================================