CloudStack supports ISOs and their attachment to guest VMs. An ISO is a read-only file that has an ISO/CD-ROM style file system. Users can upload their own ISOs and mount them on their guest VMs.
ISOs are uploaded based on a URL. HTTP is the supported protocol. Once the ISO is available via HTTP specify an upload URL such as http://my.web.server/filename.iso.
ISOs may be public or private, like templates.ISOs are not hypervisor-specific. That is, a guest on vSphere can mount the exact same image that a guest on KVM can mount.
ISO images may be stored in the system and made available with a privacy level similar to templates. ISO images are classified as either bootable or not bootable. A bootable ISO image is one that contains an OS image. CloudStack allows a user to boot a guest VM off of an ISO image. Users can also attach ISO images to guest VMs. For example, this enables installing PV drivers into Windows. ISO images are not hypervisor-specific.
To make additional operating system or other software available for use with guest VMs, you can add an ISO. The ISO is typically thought of as an operating system image, but you can also add ISOs for other types of software, such as desktop applications that you want to be installed as part of a template.
Log in to the CloudStack UI as an administrator or end user.
In the left navigation bar, click Templates.
In Select View, choose ISOs.
Click Add ISO.
In the Add ISO screen, provide the following:
Name: Short name for the ISO image. For example, CentOS 6.2 64-bit.
Description: Display test for the ISO image. For example, CentOS 6.2 64-bit.
URL: The URL that hosts the ISO image. The Management Server must be able to access this location via HTTP. If needed you can place the ISO image directly on the Management Server
Zone: Choose the zone where you want the ISO to be available, or All Zones to make it available throughout CloudStack.
Bootable: Whether or not a guest could boot off this ISO image. For example, a CentOS ISO is bootable, a Microsoft Office ISO is not bootable.
OS Type: This helps CloudStack and the hypervisor perform certain operations and make assumptions that improve the performance of the guest. Select one of the following.
If the operating system of your desired ISO image is listed, choose it.
If the OS Type of the ISO is not listed or if the ISO is not bootable, choose Other.
(XenServer only) If you want to boot from this ISO in PV mode, choose Other PV (32-bit) or Other PV (64-bit)
(KVM only) If you choose an OS that is PV-enabled, the VMs created from this ISO will have a SCSI (virtio) root disk. If the OS is not PV-enabled, the VMs will have an IDE root disk. The PV-enabled types are:
It is not recommended to choose an older version of the OS than the version in the image. For example, choosing CentOS 5.4 to support a CentOS 6.2 image will usually not work. In these cases, choose Other.
Extractable: Choose Yes if the ISO should be available for extraction.
Public: Choose Yes if this ISO should be available to other users.
Featured: Choose Yes if you would like this ISO to be more prominent for users to select. The ISO will appear in the Featured ISOs list. Only an administrator can make an ISO Featured.
Click OK.
The Management Server will download the ISO. Depending on the size of the ISO, this may take a long time. The ISO status column will display Ready once it has been successfully downloaded into secondary storage. Clicking Refresh updates the download percentage.
Important: Wait for the ISO to finish downloading. If you move on to the next task and try to use the ISO right away, it will appear to fail. The entire ISO must be available before CloudStack can work with it.
10.15.2. Attaching an ISO to a VM
In the left navigation, click Instances.
Choose the virtual machine you want to work with.
Click the Attach ISO button.
In the Attach ISO dialog box, select the desired ISO.
Click OK.
10.15.3. Changing a VM's Base Image
Every VM is created from a base image, which is a template or ISO which has been created and stored in CloudStack. Both cloud administrators and end users can create and modify templates, ISOs, and VMs.
In CloudStack, you can change an existing VM's base image from one template to another, or from one ISO to another. (You can not change from an ISO to a template, or from a template to an ISO).
For example, suppose there is a template based on a particular operating system, and the OS vendor releases a software patch. The administrator or user naturally wants to apply the patch and then make sure existing VMs start using it. Whether a software update is involved or not, it's also possible to simply switch a VM from its current template to any other desired template.
To change a VM's base image, call the restoreVirtualMachine API command and pass in the virtual machine ID and a new template ID. The template ID parameter may refer to either a template or an ISO, depending on which type of base image the VM was already using (it must match the previous type of image). When this call occurs, the VM's root disk is first destroyed, then a new root disk is created from the source designated in the template ID parameter. The new root disk is attached to the VM, and now the VM is based on the new template.
You can also omit the template ID parameter from the restoreVirtualMachine call. In this case, the VM's root disk is destroyed and recreated, but from the same template or ISO that was already in use by the VM.
