Allow Test VM RAM setting to be tunable

Due to the debian + simple-init image size, which is not a small
image, we need to support having slightly larger guest VMs in order
to allow for the image to be downloaded to the guest VM.

Add tunable setting, and default the image build test job to create
a VM with 4096 MB of RAM instead of 3072 MB.

Change-Id: Ifdccb32035fa91fe8d8200c3090973c34d453801

playbooks/roles/bifrost-create-vm-nodes/README.md

@@ -18,6 +18,12 @@ Role Variables
 
 baremetal_csv_file: "/tmp/baremetal.csv"
 
+test_vm_memory_size: Tunable setting to allow a user to define a specific
+                     amount of RAM to allocate to guest/test VMs.  Defaults
+                     to "3072". Note: if this setting is modified between
+                     test runs, you may need to undefine the test virtual
+                     machine(s) that were previously created.
+
 Dependencies
 ------------
 

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

@@ -1,3 +1,4 @@
 ---
 # defaults file for bifrost-create-vm-nodes
 baremetal_csv_file: "/tmp/baremetal.csv"
+test_vm_memory_size: "3072"

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

@@ -41,6 +41,7 @@
   script: create_vm_nodes-for-role.sh
   environment:
     NODEOUTPUT: "{{baremetal_csv_file}}"
+    VM_RAM: "{{ test_vm_memory_size }}"
   register: task_create_vm_nodes
   ignore_errors: yes
   delegate_to: localhost

scripts/test-bifrost-build-images.sh

@@ -24,7 +24,8 @@ ansible-playbook -vvvv -i inventory/localhost test-bifrost-create-vm.yaml --synt
 ansible-playbook -vvvv -i inventory/localhost test-bifrost-dynamic.yaml --syntax-check --list-tasks
 
 # Create the test VM
-ansible-playbook -vvvv -i inventory/localhost test-bifrost-create-vm.yaml
+ansible-playbook -vvvv -i inventory/localhost test-bifrost-create-vm.yaml \
+    -e test_vm_memory_size="4096"
 
 set +e