Thanks for the information. I'll work with this and get back if I get
stuck somewhere.
My immediate objective is to figure out how to pass the TLS x509
certificate information to the vxhs block device on the qemu command
line. I guess I expected some other block device (i.e. NBD) to call
the qemuBuildTLSx509CommandLine(), but got confused when I did not
find that...
On Tue, Apr 11, 2017 at 3:47 PM, John Ferlan <jfer...@redhat.com> wrote:
>
>
> On 04/10/2017 07:32 PM, ashish mittal wrote:
>> Hi,
>>
>> I'm trying to figure out what changes are needed in the libvirt vxhs
>> patch to support passing TLS X509 arguments to qemu, similar to the
>> following -
>>
>> Sample QEMU command line passing TLS credentials to the VxHS block
>> device (run in secure mode):
>> ./qemu-io --object
>> tls-creds-x509,id=tls0,dir=/etc/pki/qemu/vxhs,endpoint=client -c 'read
>> -v 66000 2.5k' 'json:{"server.host": "127.0.0.1", "server.port": "9999",
>> "vdisk-id": "/test.raw", "driver": "vxhs", "tls-creds":"tls0"}'
>>
>> I was hoping to find some NBD code related to this, but not able to
>> locate it. Any pointers will be appreciated.
>
> Well you have a couple of things to deal with... There's the creation of
> the TLS object and there's altering the parameters used for the qemu
> command based on your needs/model.
>
> First off you'll need to figure out where/how you're going to define
> where the TLS creds exist. For that, I suspect you'll have code similar
> to how chardevTLS support was added. Essentially some way to either use
> an existing TLS environment or a way to allow someone to define a vxhs
> specific environment (hint, see src/qemu/qemu_conf.c, src/qemu/qemu.conf
> - I've made changes recently there too).
>
> For the TLS object creation on the command line, see
> qemuBuildTLSx509CommandLine to see how the code builds the
> "tls-creds-x509,id=tls0,dir=/etc/pki/qemu/vxhs,endpoint=client" portion
> of your command line.
>
> I forget if hot plug was in your plan, but see qemuDomainGetTLSObjects,
> qemuDomainAddTLSObjects, and qemuDomainDelTLSObjects for that.
>
> The rest of the command line is going to be a bit tricky since using the
> "newer" driver syntax for libvirt is "sparse". Traditionally libvirt has
> used "-drive file=[$uri:]$path,format=$driver,..." (use grep "\-drive
> file" tests/*/*.args from a libvirt git directory - you can grep that
> output for gluster or rbd to see the uri format).
>
> IIUC the qemu changes correctly though, you cannot use that "file="
> syntax, instead you'll need to format the command line similar to how
> things were done for gluster to add multiple host support where the
> syntax is "-drive 'file.driver=gluster,file.volume=..." (use grep
> "\-drive file.driver" tests/*/*.args to see how this is done for gluster).
>
> That code/support was added in a series starting at commit id '22ad4a7c'
> and working your way forward through about 18 patches. Using a visual
> tool like gitk helps a lot...
>
> I think what will be easiest is to start at that commit and look "up"
> for gluster specific changes. Be careful not to fully cut-n-paste
> because there have been patches since that time to fix some issues with
> the initial implementation. I point it out only as a way for you to see
> which modules and where "similar" code exists.
>
> You'll also note there is an nbd patch in that series of patches - not
> sure how much that helps, but it perhaps gives you some amount of
> guidelines. Although I don't believe nbd was added to the command line -
> it was just a way of syntax generation/testing.
>
>
> John
>
>>
>> Thanks,
>> Ashish
>>
>> On Wed, Feb 1, 2017 at 8:36 AM, John Ferlan <jfer...@redhat.com> wrote:
>>> [...]
>>> Pressed send too soon, sigh.
>>>
>>>
>>>>>>
>>>>>> #1. Based on Peter's v2 comments, we don't want to support the
>>>>>> older/legacy syntax for VxHS, so it's something that should be removed -
>>>>>> although we should check for it being present and fail if found.
>>>>>>
>>>>>
>>>>> I am testing with changed code to return error if legacy syntax is
>>>>> found for VxHS. Also added a test case to check for failure on legacy
>>>>> syntax and it seems to pass (test #41 below).
>>>>>
>>>>> Then I added a pass test case to check conversion from new native
>>>>> syntax to XML (test #40 below). That test fails with error
>>>>> 'qemuParseCommandLineDisk:901 : internal error: missing file parameter
>>>>> in drive 'file.driver=vxhs,file.vdisk-id=eb90327c-8302-4725-9e1b...'
>>>>
>>>> The qemu_parse_command.c changes while nice to have weren't even updated
>>>> when multiple gluster servers were added (e.g. commit id '' or '7b7da9e28')
>>>> Check the changes to add the new s
>>>>
>>>> IOW: This code knows how to parse something like:
>>>>
>>>> -drive
>>>> 'file=gluster+unix:///Volume2/Image?socket=/path/to/sock,format=raw,if=none,id=drive-virtio-disk1'
>>>>
>>>> but it's clueless for:
>>>>
>>>> -drive file.driver=gluster,file.volume=Volume3,file.path=/Image.qcow2,\
>>>> file.server.0.type=tcp,file.server.0.host=example.org,file.server.0.port=6000,\
>>>> file.server.1.type=tcp,file.server.1.host=example.org,file.server.1.port=24007,\
>>>> file.server.2.type=unix,file.server.2.socket=/path/to/sock,format=qcow2,\
>>>> if=none,id=drive-virtio-disk2 \
>>>> -device virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk2,\
>>>> id=virtio-disk2
>>>>
>>>> See
>>>>>
>>>>> Looks like none of the existing tests in qemuargv2xmltest test for the
>>>>> parsing of new syntax, and qemuParseCommandLineDisk() expects to find
>>>>> 'file=' for a drive or it errors out. If this is true, will it be able
>>>>> to parse the new syntax? Some help here please!
>>>
>>> So I wouldn't expect the VxHS code to be able to do that unless you
>>> wanted to be adventurous. The good news is that this code is primarily
>>> for developers that need to take a qemu command line to generate the
>>> libvirt syntax. It has not really been kept up to date with all the most
>>> recent command line changes. I started to try over a year ago, but got
>>> very side tracked.
>>>
>>>>>
>>>>> Output from the newly added test cases (40 should pass and 41 checks
>>>>> for error) :
>>>>>
>>>>> 40) QEMU ARGV-2-XML disk-drive-network-vxhs
>>>>> ... Got unexpected warning from qemuParseCommandLineString:
>>>>> 2017-01-28 00:57:30.814+0000: 10391: info : libvirt version: 3.0.0
>>>>> 2017-01-28 00:57:30.814+0000: 10391: info : hostname:
>>>>> localhost.localdomain
>>>>> 2017-01-28 00:57:30.814+0000: 10391: error :
>>>>> qemuParseCommandLineDisk:901 : internal error: missing file parameter
>>>>> in drive
>>>>> 'file.driver=vxhs,file.vdisk-id=eb90327c-8302-4725-9e1b-4e85ed4dc251,file.server.host=192.168.0.1,file.server.port=9999,format=raw,if=none,id=drive-virtio-disk0,cache=none'
>>>>> libvirt: QEMU Driver error : internal error: missing file parameter in
>>>>> drive
>>>>> 'file.driver=vxhs,file.vdisk-id=eb90327c-8302-4725-9e1b-4e85ed4dc251,file.server.host=192.168.0.1,file.server.port=9999,format=raw,if=none,id=drive-virtio-disk0,cache=none'
>>>>> FAILED
>>>>>
>>>>> 41) QEMU ARGV-2-XML disk-drive-network-vxhs-fail
>>>>> ... Got expected error from qemuParseCommandLineString:
>>>>> libvirt: QEMU Driver error : internal error: VxHS protocol does not
>>>>> support URI syntax
>>>>> 'vxhs://192.168.0.1:9999/eb90327c-8302-4725-9e1b-4e85ed4dc251'
>>>>> OK
>>>>> 42) QEMU ARGV-2-XML disk-usb ...
>>>>> OK
>>>>>
>>>>>
>>>>>
>>>>>> #2. Is the desire to ever support more than 1 host? If not, then is the
>>>>>> "server" syntax you've borrowed from the Gluster code necessary? Could
>>>>>> you just go with the single "host" like NBD and SSH. As it relates to
>>>>>> the qemu command line - I'm not quite as clear. From the example I see
>>>>>> in commit id '7b7da9e28', the gluster syntax would have:
>>>>>>
>>>>>
>>>>> Present understanding is to have only one host. You are right, the
>>>>> "server" part is not necessary. Will have to check with the qemu
>>>>> community on this change.
>>>>>
>>>>>> +file.server.0.type=tcp,file.server.0.host=example.org,file.server.0.port=6000,\
>>>>>> +file.server.1.type=tcp,file.server.1.host=example.org,file.server.1.port=24007,\
>>>>>> +file.server.2.type=unix,file.server.2.socket=/path/to/sock,format=qcow2,\
>>>>>>
>>>>>> whereas, the VxHS syntax is:
>>>>>> +file.server.host=192.168.0.1,file.server.port=9999,format=raw,if=none,\
>>>>>>
>>>>>> FWIW: I also note there is no ".type=tcp" in your output - so perhaps
>>>>>> the "default" is tcp unless otherwise specified, but I'm sure of the
>>>>>> qemu syntax requirements in this area. I assume that since there's only
>>>>>> 1 server, the ".0, .1, .2" become unnecessary (something added by commit
>>>>>> id 'f1bbc7df4' for multiple gluster hosts).
>>>>>>
>>>>>
>>>>> That's correct. TCP is the default.
>>>>>
>>>>>> I haven't closedly followed the qemu syntax discussion, but it would it
>>>>>> would be possible to use:
>>>>>>
>>>>>> +file.host=192.168.0.1,file.port=9999
>>>>>>
>>>>>
>>>>> That is correct. Above syntax would also work for us. I will pose this
>>>>> suggestion to the qemu community and update with their response.
>>>>>
>>>
>>> It's not that important... I was looking for a simplification and
>>> generation of only what's required. You can continue using the server
>>> syntax - perhaps just leave a note/comment in the code indicating the
>>> decision point and move on.
>>>
>>> [...]
>>>
>>> John
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