Allow specification of multiple VMs

Adapt the role to allow a list of VM specifications. This involves:
  * Splitting libvirt_vm_* variables into role-scope and VM-scope.
  * Deprecating the old set of variables.

Author: Will Miller

README.md

@@ -18,6 +18,8 @@ Role Variables
 - `libvirt_vm_emulator`: path to emulator binary. If not set, the role will
   attempt to auto-detect the correct emulator to use.
 
+- `libvirt_vm_arch`: CPU architecture, default is `x86_64`.
+
 - `libvirt_vms`: list of VMs to be created/destroyed. Each one may have the
   following attributes:
 
@@ -30,8 +32,6 @@ Role Variables
 
     - `vcpus`: the number of VCPU cores to assign to the VM.
 
-    - `arch`: CPU architecture, default is `x86_64`.
-    
     - `machine`: Virtual machine type. Default is `None` if
       `engine` is `kvm`, otherwise `pc-1.0`.
 
@@ -61,8 +61,8 @@ Role Variables
 
 N.B. the following variables are deprecated: `libvirt_vm_state`,
 `libvirt_vm_name`, `libvirt_vm_memory_mb`, `libvirt_vm_vcpus`,
-`libvirt_vm_engine`, `libvirt_vm_arch`, `libvirt_vm_machine`,
-`libvirt_vm_cpu_mode`, `libvirt_vm_volumes`, `libvirt_vm_interfaces` and
+`libvirt_vm_engine`, `libvirt_vm_machine`, `libvirt_vm_cpu_mode`,
+`libvirt_vm_volumes`, `libvirt_vm_interfaces` and
 `libvirt_vm_console_log_path`. If the variable `libvirt_vms` is left unset, its
 default value will be a singleton list containing a VM specification using
 these deprecated variables.

defaults/main.yml

@@ -1,15 +1,10 @@
 ---
-# State of the VM. May be 'present' or 'absent'.
-libvirt_vm_state: present
 
-# Name of the VM.
-libvirt_vm_name:
-
-# Memory in MB.
-libvirt_vm_memory_mb:
+# Path to cache downloaded images.
+libvirt_image_cache_path:
 
-# Number of vCPUs.
-libvirt_vm_vcpus:
+# CPU architecture.
+libvirt_vm_arch: x86_64
 
 # Virtualisation engine. If not set, the role will attempt to auto-detect the
 # optimal engine to use.
@@ -19,26 +14,49 @@ libvirt_vm_engine:
 # correct emulator to use.
 libvirt_vm_emulator:
 
-# CPU architecture.
-libvirt_vm_arch: x86_64
+# A list of specifications of VMs to be created.
+# For backwards compatibility, libvirt_vms defaults to a singleton list using
+# the values of the deprecated variables below.
+# See README.md or tasks/main.yml for these attributes' defaults.
+libvirt_vms:
+      # State of the VM. May be 'present' or 'absent'.
+    - state: "{{ libvirt_vm_state }}"
 
-# Virtual machine type.
-libvirt_vm_machine: "{{ None if libvirt_vm_engine == 'kvm' else 'pc-1.0' }}"
+      # Name of the VM.
+      name: "{{ libvirt_vm_name }}"
 
-# Virtual machine CPU mode.
-libvirt_vm_cpu_mode: "{{ 'host-passthrough' if libvirt_vm_engine == 'kvm' else 'host-model' }}"
+      # Memory in MB.
+      memory_mb: "{{ libvirt_vm_memory_mb }}"
 
-# List of volumes.
-libvirt_vm_volumes: []
+      # Number of vCPUs.
+      vcpus: "{{ libvirt_vm_vcpus }}"
 
-# List of network interfaces.
-libvirt_vm_interfaces: []
+      # Virtual machine type.
+      machine: "{{ libvirt_vm_machine }}"
 
-# Path to console log file.
-libvirt_vm_console_log_path: "/var/log/libvirt-consoles/{{ libvirt_vm_name }}.log"
+      # Virtual machine CPU mode.
+      cpu_mode: "{{ libvirt_vm_cpu_mode }}"
+
+      # List of volumes.
+      volumes: "{{ libvirt_vm_volumes }}"
+
+      # List of network interfaces.
+      interfaces: "{{ libvirt_vm_interfaces }}"
+
+      # Path to console log file.
+      console_log_path: "{{ libvirt_vm_console_log_path }}"
 
-# Path to cache downloaded images.
-libvirt_vm_image_cache_path:
 
-# List of authorized SSH public keys.
-#libvirt_vm_public_keys: []
+### DEPRECATED ###
+# Use the above settings for each item within `libvirt_vms`, instead of the
+# below deprecated variables.
+
+libvirt_vm_state:
+libvirt_vm_name:
+libvirt_vm_memory_mb:
+libvirt_vm_vcpus:
+libvirt_vm_machine:
+libvirt_vm_cpu_mode:
+libvirt_vm_volumes:
+libvirt_vm_interfaces:
+libvirt_vm_console_log_path:

meta/main.yml

@@ -2,7 +2,7 @@
 galaxy_info:
   author: Mark Goddard
   description: >
-    Role to configure and create a VM on a Libvirt/KVM hypervisor
+    Role to configure and create VMs on a Libvirt/KVM hypervisor
   company: StackHPC Ltd
   license: Apache2
   min_ansible_version: 2.0

tasks/main.yml

@@ -1,11 +1,28 @@
 ---
-- block:
-    - include: autodetect.yml
-    - include: volumes.yml
-    - include: vm.yml
-  when: libvirt_vm_state == 'present'
-
-- block:
-    - include: destroy-volumes.yml
-    - include: destroy-vm.yml
-  when: libvirt_vm_state == 'absent'
+- include_tasks: autodetect.yml
+  # We need to know the engine and emulator if we're creating any new VMs.
+  when: "libvirt_vms | rejectattr('state', 'eq', 'absent')"
+
+- include_tasks: volumes.yml
+  with_items: "{{ libvirt_vms }}"
+  loop_control:
+    loop_var: vm
+  when: (vm.state | default('present')) == 'present'
+
+- include_tasks: vm.yml
+  with_items: "{{ libvirt_vms }}"
+  loop_control:
+    loop_var: vm
+  when: (vm.state | default('present')) == 'present'
+
+- include_tasks: destroy-volumes.yml
+  with_items: "{{ libvirt_vms }}"
+  loop_control:
+    loop_var: vm
+  when: (vm.state | default('present')) == 'absent'
+
+- include_tasks: destroy-vm.yml
+  with_items: "{{ libvirt_vms }}"
+  loop_control:
+    loop_var: vm
+  when: (vm.state | default('present')) == 'absent'