Configure Zun for Placement (Train+)

After the integration with placement [1], we need to configure how
zun-compute is going to work with nova-compute.

* If zun-compute and nova-compute run on the same compute node,
  we need to set 'host_shared_with_nova' as true so that Zun
  will use the resource provider (compute node) created by nova.
  In this mode, containers and VMs could claim allocations against
  the same resource provider.
* If zun-compute runs on a node without nova-compute, no extra
  configuration is needed. By default, each zun-compute will create
  a resource provider in placement to represent the compute node
  it manages.

[1] https://blueprints.launchpad.net/zun/+spec/use-placement-resource-management

Change-Id: I2d85911c4504e541d2994ce3d48e2fbb1090b813

ansible/roles/zun/templates/zun.conf.j2

@@ -98,6 +98,9 @@ lock_path = /var/lib/zun/tmp
 policy_file = {{ zun_policy_file }}
 {% endif %}
 
+[compute]
+host_shared_with_nova = {{ inventory_hostname in groups['compute'] and enable_nova | bool and not enable_nova_fake | bool }}
+
 [websocket_proxy]
 wsproxy_host = {{ api_interface_address }}
 wsproxy_port = {{ zun_wsproxy_port }}

doc/source/reference/compute/zun-guide.rst

@@ -20,6 +20,7 @@ following variables:
    enable_zun: "yes"
    enable_kuryr: "yes"
    enable_etcd: "yes"
+   enable_placement: "yes"
    docker_configure_for_zun: "yes"
 
 Docker reconfiguration requires reboostrapping before deploy.

tests/templates/globals-default.j2

@@ -67,6 +67,7 @@ enable_cinder_backend_lvm: "yes"
 enable_zun: "yes"
 enable_kuryr: "yes"
 enable_etcd: "yes"
+enable_placement: "yes"
 docker_configure_for_zun: "yes"
 {% endif %}