Abiquo 2.6


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In Abiquo 2.6, persistent virtual machines are not available in public datacenters.

Terminology

The term virtual machine template has now replaced virtual image to describe a virtual machine's disk and definition. Virtual image is still used in the API. The term persistent is now used instead of stateful .

Secondary Hard Disks on the Hypervisor Datastore Are Not Persistent

Secondary hard disks on the hypervisor datastore will always be deleted when a persistent virtual machine is undeployed.

Introduction to Persistent Virtual Machines

By default, Abiquo deploys virtual machine templates from the appliance library to the target physical infrastructure. Every time a virtual appliance is deployed, it copies the templates from the appliance library to the hypervisor with the specific virtual appliance configuration.

When you undeploy a virtual appliance, all changes made to the system volumes of the virtual machines are lost. This is because the next time you deploy the virtual appliance, the template files will be copied again from the Appliance Library to the target hypervisor.

Persistent virtual machines are stored on an external volume, so all information will be persisted on the external storage device. Persistent virtual machines will boot directly from the external persistent volume.

Prerequisites

Before you can create persistent virtual machine templates, you must configure a storage pool or generic iSCSI volumes as explained in the Manage External Storage section of Infrastructure View.

Create Persistent Virtual Machine Templates

To create a persistent virtual machine:

  1. create a persistent virtual machine template
  2. deploy the template in a virtual appliance to create the persistent virtual machine 

 

In Virtual Datacenters view, click the Persistent Virtual Machine Template tab. Click your virtual datacenter. Click the add button  at the bottom of the tab to create a new persistent template.

 

You can filter the template list by template name, and master and instance templates. The Clone button will appear when you move the mouse over a template in the list.

Click Clone to copy the template item in the list. The new template item will appear above the original item. Use the Clone function to create multiple persistent templates from the same template at the same time. Select a template item. Click the pencil icon and enter a new name for the persistent virtual machine template and click Accept.

 

Then select your external storage:

  • For managed storage, mark the tier radio box and choose the Tier (storage service level) for the persistent volume that will be created.
  • If there is generic iSCSI storage available, the volume radio button will also appear, so you can mark it to choose a Volume. You will see generic iSCSI volumes in the volume combo box, but not managed storage volumes. The size of your virtual machine when converted to raw format must be smaller than the size of the generic iSCSI volume entered by the cloud administrator.

Select more templates and storage as required. Click Start conversions. Your templates will appear in the list while they are "In progress" and then "Done" or "Failed". You can check the details in Events view.

Create Persistent Templates from the VApp Screen

You can also create persistent templates from inside a VApp. Open the VApp, then click on the Persistent Virtual Machine Templates tab. Click the add button  at the bottom of the tab to create a new persistent template.

Again, select your VM template from the template list, select storage, then click Make persistent. When the persistent template is in progress, it will be shown with a spinning arrow superimposed.

The template in progress will also be shown with a spinning grey indicator on the Persistent Virtual Machines tab in Virtual Datacenters view. When they are ready, your templates will appear with a green indicator in this view.

If you use your persistent template in a virtual machine, the details of the virtual machine will also be shown in this view.

Modify Persistent Templates

To modify a persistent template, select it on the Persistent Virtual Machine Templates tab and click the edit button at the bottom right of the template list. As for a standard template, you can edit all the fields except the size of the Hard disk. 

 

Delete Failed Persistent Templates

If a persistent conversion was not successful, it will be marked on the Persistent Virtual Machines tab with a warning (warning) symbol. You can remove a failed template in the Persistent Virtual Machine Templates tab by clicking the  delete button.

Persistent Virtual Machines

See Create Persistent Virtual Machines

Cannot Share Persistent Virtual Machine Templates

Persistent virtual machine templates  can only be used in ONE virtual appliance  at a time, in order to avoid concurrent modifications to the virtual machine.

Because persistent VM templates cannot be shared, they do not appear in the Appliance Library View. To share a persistent virtual machine template, deploy a persistent virtual machine and create an  instance , which will be available for deployment in other virtual machines.

Reuse Persistent Templates

When a persistent virtual machine is deleted from the virtual appliance, the template remains on the volume on the storage device.

This means that the persistent virtual machine template will appear in the Persistent Virtual Machine Templates tab again and it may be re-used in other virtual appliances:

Persistent Virtual Machine Template Volumes

If a persistent template was created successfully, it will also appear in the Volume tab of the Virtual Datacenter with a green indicator.

Move Persistent Templates Between Virtual Datacenters

Drag and drop persistent templates that are not deployed from the template list to another virtual datacenter in the VIRTUAL DATACENTER list.

Delete Persistent Template Volumes

You can delete a template that is not used in a virtual appliance, marked with a red indicator. Select the template and click the  delete button to remove the template.

Persistent Template Volumes on ESX

Abiquo avoids performing a full HBA rescan of storage on ESX or ESXi for performance reasons. Instead it checks for a raw device mapping for a given IQN and LUN. However, if a volume has been removed or replaced in the storage device, Abiquo may try to attach a volume that does not exist or is completely different to one previously configured, causing an error. This situation may occur with: managed storage volumes, generic iSCSI volumes and persistent virtual machines. It can be resolved by manually performing a full HBA rescan of all ESX or ESXi hosts that had raw device mappings for the devices involved.

The Persistent and Non-persistent Approach

There are two provisioning approaches supported by the Abiquo platform: non-persistent and persistent.

The Non-persistent Approach 

This is the default process in the Abiquo platform. Abiquo provisions the virtual machine and copies the disk to the cloud node. When the user undeploys the virtual appliance, the data on the system disk will be overwritten.

The Persistent Approach

 Persistence is the typical approach in a datacenter virtualization environment. Abiquo provisions the virtual machine and stores the disk on external storage. When the user undeploys the virtual appliance, the virtual machine data is kept.

What Happens When I Click Make Persistent?

The following diagram shows a simplified example of the persistent template process.