is a very interesting sentence, and it seems to be very useful. First
time I read it, I thought: “Do I need to have 3 different images?
Can I have same image running on any hypervisor?” Answers are yes
to both question. Depending on how you would run your image you could
need have different images for different hypervisors or just use an
single image regardless the underlying hypervisor.
going deeper on how IBM SmartCloud Provisioning deploys virtual
images, I would discuss different hypervisors. Each of them has its
own peculiarity, allowing you to leverage different features,
implemented in different ways. This lead us to deal with different
hypervisor limitations. Here the following are most common
and Xen are able to manage SCSI devices, but not KVM
and Xen can use virtio drivers but not VMWare
uses a proprietary agent inside the guest OS (VMWare tools) which
does not work with Xen or KVM
uses vmdk file format, which is a proprietary format
of these differences can prevent an image from working on any
hypervisor. It is clear that if you do not pay attention on how you
create your base images, you might need different images for the
different hypervisors. So next step is understanding how we should
create a “magic image” able to run everywhere.
point is to figure out list of similarity between different
any hypervisor type support the raw format.
type: any hypervisor type supports ide device.
configuration: hypervisors do not require specific configurations,
but the manager could.
with IBM SmartCloud Provisioning you will not have any issue from any
of the previous points. In fact before creating a base image you
should just follow a few rules to ensure portability.
requires specific OS configuration regardless the underlying
hypervisor. You can find all needed information on how to build your
image at the info center site:
is important to use raw format, for the initial image. Here we have
an interesting problem: how to create a VMWare image in raw format.
The answer is very simple: we are creating a fully portable image, so
you can use KVM to build such master image and than run it
this point we have our raw image, fulfilling all requirements from
the hypervisor manager. What is next step? You need to register it
into IBM SmartCloud Provisioning. To do that you can use either the
administrative UI or CLI. Regardless the user interface you are using
just remember to use following settings during registration:
not enable virtio
finally have a fully portable image. IBM SmartCloud Provisioning will
decide by itself which will be the most appropriate compute node to
run your “magic image”.
though the described process is very easy, there could be some cases
where you cannot follow it. This is just in case you already have
your image in a proprietary format, and you need to use them. In this
case you have Virtual Image Library helping you. It is a very useful
IBM SmartCloud Provisioning component able to manage images
federating different hypervisors. It has capability to check image
into its own repository so that you can then check them out to a
different federated virtualization environment. And during this
process it will convert the image format for you.
it you will be able for example to check in a VMWare image and then
check the same image out to IBM Smartcloud Provisioning. Resulting
in a raw format image. Next interesting question is if it will run or
not. The answer strongly depends on compute node type and image
configuration. For what previously discussed, you should care about
configuration: as I said IBM SmartCloud Provisioning requires images
to have some OS configuration. To have final working image you must
ensure that the initial VMWare image has all required configuration
before stating importing it into Virtual Image Library. Otherwise
it will not able to start (for example if image does not have DHCP
configured, it will never get a valid IP)
type: if you only have KVM compute node within your IBM SmartCloud
Provisioning an image using SCSI device will not be able to run at
all. To have it running you must have at least one VMWare compute
node. If initial image is using an ide device, than you will not
have any trouble.
addition to image format conversion Virtual image Library is also
able to modify Windows device driver. In the process of moving an
image from VMWare to Virtual Image Library and than to IBM SmartCloud
Provisioning, the application change Windows configuration allowing
it to run into any hypervisor.
information about previous topics can be found at IBM info center