NFS backend support to store Nova instances

Allow to store instances on a NFS share.

* New parameters: nfs_enabled, nfs_device and filesystem_store_datadir
* Disabled by default
* Unit tests with 3 contexts to validate all eventual cases

manifests/compute/hypervisor.pp

@@ -33,6 +33,22 @@
 #   (optional) Allow to manage or not TSO issue.
 #   Default to true.
 #
+# [*nfs_enabled*]
+#   (optional) Store (or not) instances on a NFS share.
+#   Defaults to false
+#
+# [*nfs_device*]
+#   (optional) NFS device to mount
+#   Example: 'nfs.example.com:/vol1'
+#   Required when nfs_enabled is at true.
+#   Defaults to false
+#
+# [*filesystem_store_datadir*]
+#   (optional) Full path of data directory to store the instances.
+#   Don't modify this parameter if you don't know what you do.
+#   You may have side effects (SElinux for example).
+#   Defaults to '/var/lib/nova/instances'
+#
 class cloud::compute::hypervisor(
   $server_proxyclient_address = '127.0.0.1',
   $libvirt_type               = 'kvm',
@@ -47,6 +63,10 @@ class cloud::compute::hypervisor(
   $vm_rbd                     = false,
   $volume_rbd                 = false,
   $manage_tso                 = true,
+  # when using NFS storage backend
+  $nfs_enabled                = false,
+  $nfs_device                 = false,
+  $filesystem_store_datadir   = '/var/lib/nova/instances',
   # set to false to keep backward compatibility
   $ks_spice_public_proto      = false,
   $ks_spice_public_host       = false,
@@ -84,6 +104,35 @@ class cloud::compute::hypervisor(
     $ks_spice_public_host_real = $ks_nova_public_host
   }
 
+  if $nfs_enabled {
+    if ! $vm_rbd {
+      # There is no NFS backend in Nova.
+      # We mount the NFS share in filesystem_store_datadir to fake the
+      # backend.
+      if $nfs_device {
+        nova_config { 'DEFAULT/instances_path': value => $filesystem_store_datadir; }
+        $nfs_mount = {
+          "${filesystem_store_datadir}" => {
+            'ensure' => 'present',
+            'fstype' => 'nfs',
+            'device' => $nfs_device
+          }
+        }
+        ensure_resource('class', 'nfs', {
+          mounts => $nfs_mount
+        })
+        # Not using /var/lib/nova/instances may cause side effects.
+        if $filesystem_store_datadir != '/var/lib/nova/instances' {
+          warning('filesystem_store_datadir is not /var/lib/nova/instances so you may have side effects (SElinux, etc)')
+        }
+      } else {
+        fail('When running NFS backend, you need to provide nfs_device parameter.')
+      }
+    } else {
+      fail('When running NFS backend, vm_rbd parameter cannot be set to true.')
+    }
+  }
+
   file{ '/var/lib/nova/.ssh':
     ensure  => directory,
     mode    => '0700',

spec/classes/cloud_compute_hypervisor_spec.rb

@@ -469,6 +469,41 @@ describe 'cloud::compute::hypervisor' do
           )
       end
     end
+
+    context 'when storing instances on a NFS share' do
+      before :each do
+        params.merge!(
+          :nfs_enabled => true,
+          :nfs_device  => 'nfs.example.com:/vol1' )
+      end
+      it 'configure nova instances path and NFS mount' do
+        should contain_nova_config('DEFAULT/instances_path').with('value' => '/var/lib/nova/instances')
+        should contain_mount('/var/lib/nova/instances').with({
+          'ensure' => 'present',
+          'fstype' => 'nfs',
+          'device' => 'nfs.example.com:/vol1',
+        })
+      end
+    end
+
+    context 'when storing instances on a NFS share without nfs_device' do
+      before :each do
+        params.merge!(
+          :nfs_enabled => true,
+          :nfs_device  => false )
+      end
+      it_raises 'a Puppet::Error', /When running NFS backend, you need to provide nfs_device parameter./
+    end
+
+    context 'when storing instances on a NFS share with vm_rbd enabled' do
+      before :each do
+        params.merge!(
+          :nfs_enabled => true,
+          :vm_rbd      => true,
+          :nfs_device  => 'nfs.example.com:/vol1' )
+      end
+      it_raises 'a Puppet::Error', /When running NFS backend, vm_rbd parameter cannot be set to true./
+    end
  end
 
   context 'on Debian platforms' do
@@ -476,7 +511,9 @@ describe 'cloud::compute::hypervisor' do
       { :osfamily        => 'Debian',
         :operatingsystem => 'Debian',
         :vtx             => true,
-        :concat_basedir  => '/var/lib/puppet/concat'
+        :concat_basedir  => '/var/lib/puppet/concat',
+        # required for rpcbind module
+        :lsbdistid       => 'Debian'
       }
     end
 
@@ -485,9 +522,11 @@ describe 'cloud::compute::hypervisor' do
 
   context 'on RedHat platforms' do
     let :facts do
-      { :osfamily => 'RedHat',
+      { :osfamily          => 'RedHat',
-        :vtx             => true,
+        :vtx               => true,
-        :concat_basedir => '/var/lib/puppet/concat'
+        :concat_basedir    => '/var/lib/puppet/concat',
+        # required for nfs module
+        :lsbmajdistrelease => '7'
       }
     end