(DIO-1059) Optionally add snapshot tuning params at clone time

lib/vmpooler/providers/vsphere.rb

@@ -306,19 +306,26 @@ def create_vm(pool_name, new_vmname)
 
             template_vm_object = find_template_vm(pool, connection)
 
+            extra_config = [
+              { key: 'guestinfo.hostname', value: new_vmname }
+            ]
+
+            if pool.key?('snapshot_mainMem_ioBlockPages')
+              ioblockpages = pool['snapshot_mainMem_ioBlockPages']
+              extra_config.push(
+                { key: 'mainMem.ioBlockPages', value: ioblockpages }
+              )
+            end
+            if pool.key?('snapshot_mainMem_iowait')
+              iowait = pool['snapshot_mainMem_iowait']
+              extra_config.push(
+                { key: 'mainMem.iowait', value: iowait }
+              )
+            end
+
             # Annotate with creation time, origin template, etc.
             # Add extraconfig options that can be queried by vmtools
-            config_spec = RbVmomi::VIM.VirtualMachineConfigSpec(
-              annotation: JSON.pretty_generate(
-                name: new_vmname,
-                created_by: provider_config['username'],
-                base_template: template_path,
-                creation_timestamp: Time.now.utc
-              ),
-              extraConfig: [
-                { key: 'guestinfo.hostname', value: new_vmname }
-              ]
-            )
+            config_spec = create_config_spec(new_vmname, template_path, extra_config)
 
             # Check if alternate network configuration is specified and add configuration
             if pool.key?('network')
@@ -358,6 +365,18 @@ def create_vm(pool_name, new_vmname)
           vm_hash
         end
 
+        def create_config_spec(vm_name, template_name, extra_config)
+          RbVmomi::VIM.VirtualMachineConfigSpec(
+            annotation: JSON.pretty_generate(
+              name: vm_name,
+              created_by: provider_config['username'],
+              base_template: template_name,
+              creation_timestamp: Time.now.utc
+            ),
+            extraConfig: extra_config
+          )
+        end
+
         def create_relocate_spec(target_datastore, target_datacenter_name, pool_name, connection)
           pool = pool_config(pool_name)
           target_cluster_name = get_target_cluster_from_config(pool_name)

spec/unit/providers/vsphere_spec.rb

@@ -689,6 +689,37 @@
         expect(result['name']).to eq(vmname)
       end
     end
+
+    context 'Given valid snapshot tuning settings' do
+      let(:folder_object) { mock_RbVmomi_VIM_Folder({ :name => 'pool1'}) }
+      let(:now) { Time.now }
+      let(:config_spec) {
+        [
+          { key: 'guestinfo.hostname', value: vmname },
+          { key: 'mainMem.ioBlockPages', value: '300' },
+          { key: 'mainMem.iowait', value: '2' }
+        ]
+      }
+
+      before(:each) do
+        template_vm = new_template_object
+        allow(subject).to receive(:find_template_vm).and_return(new_template_object)
+        allow(template_vm).to receive(:CloneVM_Task).and_return(clone_vm_task)
+        allow(clone_vm_task).to receive(:wait_for_completion).and_return(new_vm_object)
+        allow(subject).to receive(:find_vm_folder).and_return(folder_object)
+        allow(Time).to receive(:now).and_return(Time.now)
+        config[:pools][0]['snapshot_mainMem_ioBlockPages'] = '300'
+        config[:pools][0]['snapshot_mainMem_iowait'] = '2'
+      end
+
+      it 'should apply the appropriate extraConfig settings' do
+        result = subject.create_config_spec(vmname, "template1", config_spec)
+        expect(result.extraConfig).to include(
+          { :key => 'mainMem.ioBlockPages', :value => '300' },
+          { :key => 'mainMem.iowait', :value => '2'}
+        )
+      end
+    end
   end
 
   describe '#set_network_device' do

vmpooler.yaml.example

@@ -654,6 +654,15 @@
 #       The datacenter within vCenter to manage VMs.
 #       (optional: default is the first datacenter in vSphere)
 #
+#     - snapshot_mainMem_ioBlockPages
+#       Provisions VMs with the option "mainMem.ioBlockPages". This setting can be useful
+#       (paired with mainMem.iowait below) for tuning the performance of snapshot management actions.
+#       See: https://kb.vmware.com/s/article/76687
+#
+#     - snapshot_mainMem_iowait
+#       Provisions VMs with the option "mainMem.iowait". This setting can be useful
+#       for tuning the performance of snapshot management actions
+#
 # Example:
 
 :pools:
@@ -677,3 +686,5 @@
     ready_ttl: 1440
     provider: vsphere
     create_linked_clone: false
+    snapshot_mainMem_ioBlockPages: '2048'
+    snapshot_mainMem_iowait: '0'