[yocto] live image types and qemu machines

[Barros Pena, Belen]

It definitely helps: thanks!

>From what you say the following selections impact the image types:
machine, base image and distro.

I need to give this a bit of thought. I might be back with even more
questions (I hope that's ok).

Have a great weekend.

Belen

On 15/06/2012 17:16, "Darren Hart" <dvhart at linux.intel.com> wrote:

>
>
>On 06/15/2012 08:56 AM, Barros Pena, Belen wrote:
>> I'll try to explain:
>> 
>> Your answer to my question was that we should allow outputting live
>>images
>> when building qemu machines because it could be useful to run those live
>> images in the emulator, but the emulator is not currently capable of
>> running live images (although it probably will in the future).
>> 
>> If I have understood correctly (and this is a big if), it probably makes
>> no sense to allow people to select live image types when building qemu
>> images because right now they can do nothing with them: I guess they
>> cannot deploy them to hardware, and they cannot run them in the emulator
>> either. I wouldn't allow them to combine qemu and live images on the
>>basis
>> that this might change in the future.
>> 
>> The fact that the emulator cannot run live images also impacts the next
>> steps we provide once the image has been built. If we allowed Hob users
>>to
>> build for a qemu machine selecting ext2 and iso as the image types:
>> 
>> - if the emulator could run the iso image we would need to ask those
>>users
>> which image they would like to run (iso or ext2)
>> - if the emulator could not run the iso image, we could run the emulator
>> without asking them questions because the only file we could run is the
>> ext2
>> 
>> Sorry for the longwinded answer: I hope it makes sense.
>> 
>> Having said all this, I am still very much struggling to understand the
>> relationship between machines, base images and image types. This
>> relationship should inform the way we design the Hob interface. In the
>> existing settings dialog, you select image types independently of the
>> machine and base image you are building. Your selections will apply to
>>any
>> machine-base image combinations you can create within Hob. I am still
>> trying to work out if this design is appropriate.
>> 
>> On one side, I hear there are file types that make no sense for certain
>> machines. The main example I could think of was live images and qemu
>> machines (hence my question). On the other side, Richard spoke about
>>using
>> the IMAGE_FSTYPES values as default values for each base image, which
>> tells me there must also be a relationship between base images and image
>> types.
>> 
>> If anybody would like to volunteer to help me understand how machines,
>> base images and image types relate to each other, please let me know.
>>Any
>> help would be much appreciated :)
>
>OK, let me take a stab at this.
>
>base image: The image recipe to build, this defines the content of the
>image such as which packages are installed. For example:
>  core-image-minimal
>  core-image-base
>  core-image-sato
>
>image type: The format of the resulting image. All of the base images
>can be built as any of the image types, but the distro and machine
>definitions define which are allowed for the specific machine.
>  ext2
>  ext3
>  tar.gz
>  cpio.gz
>  hddimg
>  vmdk
>
>machine: The definition of the hardware (or emulator) we are building
>the image for. This defines things like architecture, compiler options,
>as well as adding dependencies on packages which are required or
>recommended, this extends the list of packages defined in the image
>recipe. For example, core-image-sato will provide the EMGD graphics
>drivers for the crownbay machine and the i915 drivers for the n450. The
>machine definition also modifies the IMAGE_FSTYPES list as appropriate
>for the hardware.
>
>distro: The distro definition, such as poky, poky-tiny, angstrom, etc.
>sets various policies about how things are built. This can include
>package format (rpm, deb. etc), image fstypes, and preferred packages
>for various configurable features like the kernel, C library, init
>system, etc. This also impacts the contents and format of the resulting
>image.
>
>Richard's suggestion to build the dialog from the IMAGE_FSTYPES makes
>sense as it will allow you to list ONLY the image types that are
>buildable for the selected distro and machine.
>
>Does that help?
>
>--
>Darren
>
>
>> 
>> Thanks!
>> 
>> Belen
>> 
>> On 15/06/2012 15:46, "Darren Hart" <dvhart at linux.intel.com> wrote:
>> 
>>> On 06/15/2012 07:39 AM, Barros Pena, Belen wrote:
>>>> Thanks for clarifying this, Darren. I think right now we need to
>>>>design
>>>> for what the current emulator can do. When things change, we should
>>>> remember to update Hob.
>>>
>>> You suggested that this had a significant impact on the dialog for
>>> selecting images. I thought knowing that qemu+live should/will be a
>>> support situation would prevent you having to redesign the dialog
>>>later,
>>> as well as other design decisions that might stem from the assumption
>>> that live images were not supported under emulation.
>>>
>>> --
>>> Darren
>>>
>>>>
>>>> Belen
>>>>
>>>> On 15/06/2012 15:31, "Darren Hart" <dvhart at linux.intel.com> wrote:
>>>>
>>>>>
>>>>>
>>>>> On 06/15/2012 06:04 AM, Barros Pena, Belen wrote:
>>>>>> Sorry, Darren and Liming: I have one more question about this.
>>>>>>Liming,
>>>>>> correct me if I am wrong, but you mentioned that the only files that
>>>>>> can
>>>>>> be run on the qemu emulator are ext2 and ext3. But Darren's answer
>>>>>> seems
>>>>>> to suggest that you can also run hddimg and iso files in the qemu
>>>>>> emulator.
>>>>>>
>>>>>> Is this correct, or am I getting totally confused?
>>>>>
>>>>>
>>>>> With the current implementation of the runqemu command and the
>>>>>current
>>>>> configuration of the qemu hardware, this is true. However, this will
>>>>> change in the future as people have run into this and asked for
>>>>> enhancements to allow it.
>>>>>
>>>>> --
>>>>> Darren
>>>>>
>>>>>>
>>>>>> Thanks!!
>>>>>>
>>>>>> Belen
>>>>>>
>>>>>> On 15/06/2012 10:33, "Barros Pena, Belen"
>>>>>> <belen.barros.pena at intel.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Thanks Darren and Liming.
>>>>>>>
>>>>>>> It sounds like we should keep things as they are, and that we'll
>>>>>>> need a
>>>>>>> screen that gives you options to both run and deploy an image when
>>>>>>> you
>>>>>>> have built for qemu selecting image types ext2 or ext3 and live.
>>>>>>>
>>>>>>> Belen
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On 14/06/2012 22:13, "Darren Hart" <dvhart at linux.intel.com> wrote:
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 06/14/2012 08:09 AM, Barros Pena, Belen wrote:
>>>>>>>>> Hi all,
>>>>>>>>>
>>>>>>>>> The current Hob allows you to build images for a qemu machine
>>>>>>>>> selecting
>>>>>>>>> 'live' as your image type. To me (with my pitiful knowledge) this
>>>>>>>>> doesn't
>>>>>>>>> make much sense: would I want to deploy an image built for a
>>>>>>>>> virtualisation environment in a real piece of hardware?
>>>>>>>>>
>>>>>>>>> So here goes a question: should we allow Hob users, who are
>>>>>>>>>mainly
>>>>>>>>> people
>>>>>>>>> new to the Yocto project, to select the 'live' image type when
>>>>>>>>> building
>>>>>>>>> images for qemu machines?
>>>>>>>>>
>>>>>>>>
>>>>>>>> In my opinion: YES. The reason is that this allows you to test the
>>>>>>>> live
>>>>>>>> image format and the boot mechanism on virtualized hardware. This
>>>>>>>> is a
>>>>>>>> valuable development tool.
>>>>>>>>
>>>>>>>> --
>>>>>>>> Darren
>>>>>>>>
>>>>>>>>> This might sound like a silly question, but it has a pretty big
>>>>>>>>> impact
>>>>>>>>> on
>>>>>>>>> the Settings dialog and on the number of variations we need to
>>>>>>>>> create
>>>>>>>>> for
>>>>>>>>> our 'Image details' screen, which appears after the build
>>>>>>>>>finishes
>>>>>>>>> and
>>>>>>>>> displays logical next steps (like run the image or deploy your
>>>>>>>>> image
>>>>>>>>> to
>>>>>>>>> external storage).
>>>>>>>>>
>>>>>>>>> Any help with this would be much appreciated.
>>>>>>>>>
>>>>>>>>> Thanks!
>>>>>>>>>
>>>>>>>>> Belen
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 
>>>>>>>>>------------------------------------------------------------------
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>>>>>>>>> https://lists.yoctoproject.org/listinfo/yocto
>>>>>>>>>
>>>>>>>>
>>>>>>>> -- 
>>>>>>>> Darren Hart
>>>>>>>> Intel Open Source Technology Center
>>>>>>>> Yocto Project - Linux Kernel
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> 
>>>>>>>--------------------------------------------------------------------
>>>>>>>-
>>>>>>> Intel Corporation (UK) Limited
>>>>>>> Registered No. 1134945 (England)
>>>>>>> Registered Office: Pipers Way, Swindon SN3 1RJ
>>>>>>> VAT No: 860 2173 47
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>>>>>>> This e-mail and any attachments may contain confidential material
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>>>>>>
>>>>>
>>>>> -- 
>>>>> Darren Hart
>>>>> Intel Open Source Technology Center
>>>>> Yocto Project - Linux Kernel
>>>>>
>>>>>
>>>>
>>>
>>> -- 
>>> Darren Hart
>>> Intel Open Source Technology Center
>>> Yocto Project - Linux Kernel
>>>
>>>
>> 
>
>-- 
>Darren Hart
>Intel Open Source Technology Center
>Yocto Project - Linux Kernel
>
>

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