Disable DHCP on the libvirt network rather than doing killall dnsmasq

We're doing a weird thing: first we enable DHCP in libvirt, then we killall
dnsmasq to stop it. Just don't enable it in the first plac

Change-Id: I539ffbfc5d4d004d27aaae0f83fef649f0e5be8c

playbooks/roles/bifrost-create-vm-nodes/defaults/main.yml

@@ -27,9 +27,6 @@ network_interface: "virbr0"
 test_vm_network: "{{ lookup('env', 'VM_NET_BRIDGE') | default('default', true) }}"
 test_vm_network_ip: "192.168.122.1"
 test_vm_network_netmask: "255.255.255.0"
-test_vm_network_enable_dhcp: true
-test_vm_network_dhcp_start: "192.168.122.2"
-test_vm_network_dhcp_end: "192.168.122.254"
 
 test_vm_storage_pool: "{{ lookup('env', 'LIBVIRT_STORAGE_POOL') | default('default', true) }}"
 test_vm_storage_pool_path: "/var/lib/libvirt/images"

playbooks/roles/bifrost-create-vm-nodes/templates/net.xml.j2

@@ -6,11 +6,5 @@
     </nat>
   </forward>
   <bridge name='{{ network_interface }}' stp='on' delay='0'/>
-  <ip address='{{ test_vm_network_ip }}' netmask='{{ test_vm_network_netmask }}'>
+  <ip address='{{ test_vm_network_ip }}' netmask='{{ test_vm_network_netmask }}' />
-  {% if test_vm_network_enable_dhcp | bool %}
-    <dhcp>
-      <range start='{{ test_vm_network_dhcp_start }}' end='{{ test_vm_network_dhcp_end }}'/>
-    </dhcp>
-  {% endif %}
-  </ip>
 </network>

playbooks/roles/bifrost-ironic-install/tasks/start.yml

@@ -56,14 +56,6 @@
 - name: "Stop dnsmasq explicitly."
   service: name=dnsmasq state=stopped
 
-# NOTE(Shrews) When testing, we want to use our custom dnsmasq.conf file,
-# not the one supplied by libvirt. And the libvirt started dnsmasq processes
-# are not controlled by upstart, so we need to manually kill those.
-- name: "Stop existing libvirt dnsmasq processes"
-  command: killall -9 -w dnsmasq
-  when: testing | bool == true and include_dhcp_server | bool == true
-  ignore_errors: yes
-
 - name: "Ensure dnsmasq is running with current config"
   service: name={{ item }} state=restarted enabled=yes
   loop:

releasenotes/notes/test_vm_network_enable_dhcp-78923ef94b44e6d1.yaml

@@ -0,0 +1,11 @@
+---
+fixes:
+  - |
+    Removes the ``test_vm_network_enable_dhcp`` option and disables DHCP on
+    the libvirt network instead of unconditionally killing all dnsmasq
+    processes on the machine.
+upgrade:
+  - |
+    Bifrost will no longer kill all running dnsmasq processes for you. If you
+    have dnsmasq processes that are not managed by systemd, you have to stop
+    them yourself.