[Kimchi-devel] [PATCH] Issue #999: Attach storage to guest on s390x without libvirt

Aline Manera alinefm at linux.vnet.ibm.com
Tue Sep 20 15:03:51 UTC 2016



On 09/20/2016 03:41 AM, Archana Singh wrote:
>
>
>
> On 09/19/2016 10:19 PM, Aline Manera wrote:
>>
>>
>> On 09/19/2016 12:33 PM, Harshal Patil wrote:
>>> Harshal Patil
>>> E-mail: harshal.patil at in.ibm.com <mailto:harshal.patil at in.ibm.com>
>>>
>>>     ----- Original message -----
>>>     From: Aline Manera <alinefm at linux.vnet.ibm.com>
>>>     Sent by: kimchi-devel-bounces at ovirt.org
>>>     To: harshalp at linux.vnet.ibm.com, Kimchi Devel
>>>     <kimchi-devel at ovirt.org>
>>>     Cc:
>>>     Subject: Re: [Kimchi-devel] [PATCH] Issue #999: Attach storage
>>>     to guest on s390x without libvirt
>>>     Date: Sat, Sep 17, 2016 1:03 AM
>>>
>>>     On 09/12/2016 06:55 AM, harshalp at linux.vnet.ibm.com wrote:
>>>     > From: Harshal Patil <harshalp at linux.vnet.ibm.com>
>>>     >
>>>     > This patch enables direct storage attachment to guests running
>>>     > on s390x arch without going through libvirt
>>>     >
>>>     > Signed-off-by: Harshal Patil <harshalp at linux.vnet.ibm.com>
>>>     > ---
>>>     >   docs/API.md         |  3 +++
>>>     >   i18n.py             |  3 +++
>>>     >   model/vmstorages.py | 25 +++++++++++++++++++++++--
>>>     >   utils.py            |  2 +-
>>>     >   4 files changed, 30 insertions(+), 3 deletions(-)
>>>     >
>>>     > diff --git a/docs/API.md b/docs/API.md
>>>     > index 6678ac5..c9d5d2a 100644
>>>     > --- a/docs/API.md
>>>     > +++ b/docs/API.md
>>>     > @@ -239,6 +239,9 @@ Represents a snapshot of the Virtual
>>>     Machine's primary monitor.
>>>     >       * path: Path of cdrom iso.
>>>     >       * pool: Storage pool which disk image file locate in.
>>>     >       * vol: Storage volume name of disk image.
>>>     > +    * dir_path: s390x specific attribute to attach direct
>>>     storage without libvirt
>>>     > +    * format: s390x specific attribute specify the format of
>>>     direct storage
>>>     > +    * size: s390x specific attribute to specify the size of
>>>     direct storage
>>>     >
>>>     >   ### Sub-resource: storage
>>>     >   **URI:** /plugins/kimchi/vms/*:name*/storages/*:dev*
>>>     > diff --git a/i18n.py b/i18n.py
>>>     > index fc7dbc7..ceb4286 100644
>>>     > --- a/i18n.py
>>>     > +++ b/i18n.py
>>>     > @@ -332,6 +332,9 @@ messages = {
>>>     >       "KCHVMSTOR0016E": _("Volume already in use by other
>>>     virtual machine."),
>>>     >       "KCHVMSTOR0017E": _("Only one of path or pool/volume can
>>>     be specified to add a new virtual machine disk"),
>>>     >       "KCHVMSTOR0018E": _("Volume chosen with format
>>>     %(format)s does not fit in the storage type %(type)s"),
>>>     > +    "KCHVMSTOR0019E": _("On s390x arch one of pool, path of
>>>     dir_path must be specified"),
>>>     > +    "KCHVMSTOR0020E": _("On s390x arch 'format' must be
>>>     specified while attaching disk to virtual machine"),
>>>     > +    "KCHVMSTOR0021E": _("Virtual disk already exists on the
>>>     system: %(disk_path)s"),
>>>     >
>>>     >       "KCHSNAP0001E": _("Virtual machine '%(vm)s' must be
>>>     stopped before creating a snapshot of it."),
>>>     >       "KCHSNAP0002E": _("Unable to create snapshot '%(name)s'
>>>     on virtual machine '%(vm)s'. Details: %(err)s"),
>>>     > diff --git a/model/vmstorages.py b/model/vmstorages.py
>>>     > index 2e9f783..156a16f 100644
>>>     > --- a/model/vmstorages.py
>>>     > +++ b/model/vmstorages.py
>>>     > @@ -17,6 +17,7 @@
>>>     >   # License along with this library; if not, write to the Free
>>>     Software
>>>     >   # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
>>>     MA  02110-1301 USA
>>>     >
>>>     > +import os
>>>     >   import string
>>>     >   from lxml import etree
>>>     >
>>>     > @@ -30,6 +31,7 @@ from wok.plugins.kimchi.model.storagevolumes
>>>     import StorageVolumeModel
>>>     >   from wok.plugins.kimchi.model.utils import get_vm_config_flag
>>>     >   from wok.plugins.kimchi.model.vms import DOM_STATE_MAP, VMModel
>>>     >   from wok.plugins.kimchi.osinfo import lookup
>>>     > +from wok.plugins.kimchi.utils import create_disk_image, is_s390x
>>>     >   from wok.plugins.kimchi.xmlutils.disk import
>>>     get_device_node, get_disk_xml
>>>     >   from wok.plugins.kimchi.xmlutils.disk import
>>>     get_vm_disk_info, get_vm_disks
>>>     >
>>>     > @@ -82,11 +84,30 @@ class VMStoragesModel(object):
>>>     >           # Path will never be blank due to API.json verification.
>>>     >           # There is no need to cover this case here.
>>>     >           if not ('vol' in params) ^ ('path' in params):
>>>     > -            raise InvalidParameter("KCHVMSTOR0017E")
>>>     > +            if not is_s390x():
>>>     > +                raise InvalidParameter("KCHVMSTOR0017E")
>>>     > +
>>>
>>>     > +            if 'dir_path' not in params:
>>>     > +                raise InvalidParameter("KCHVMSTOR0019E")
>>>
>>>     >The dir_path is exclusively for s390x. You need to add this
>>>     verification
>>>     >too.
>>>
>>> Not required. Check the condition again (The line which says 'if not 
>>> is_s390x()'). Only if the platform is s390x it will enter the code 
>>> path where 'dir_path' is checked so there is no need to check for 
>>> s390x arch again. I have tested this flow on x86 as well as on 
>>> s390x, and it works fine.
>>
>>
>> Sorry but how the first condition is related to the second one?!
>>
>> If I am x86 and I have specified a 'vol' or a 'path' and not a 
>> 'dir_path' as it is exclusively for s390x, it will raise the dir_path 
>> exception (the second condition).
>>
>> So or you add a is_s390x() condition to the second statement or you 
>> place the whole first block in a if conduction:
>>
>> if not is390x():
>>      if not (vol in params) ^ (path in params):
>>         (...)
>> else:
>>       if dir_path not in params:
>>           raise ...
>>
> Below is the flow:
>
> 1) On x86, if path or volume is not present in params then raise 
> Invalid parameter(KCHVMSTOR0017E). (Same as it is in upstream code)
> 2) On x86 or s390x, if any one of them is present don't raise invalid 
> parameter(KCHVMSTOR0017E).. (Same as it is in upstream code)
> 3) On s390x, if path or volume is not present instead of raising 
> invalid parameter, it should go and check for dir_path and if dir_path 
> is also not present then only raise Invalid parameter(KCHVMSTOR0019E).
>
> So on x86, if I have specified a vol or a path then it will not go 
> inside first if itself(not ('vol' in params) ^ ('path' in params) will 
> be false).
> and on x86, if I have neither vol nor path then it will go inside 
> first if and also second one and raise invalid parameter.
>
> And on x86, due to first nested 'if' (that is not is_s390x()) it will 
> never go to second nested 'if' ('dir_path' not in params).
>
> In Summary, on x86 if I have neither vol nor path then it should raise 
> exception KCHVMSTOR0017E (same as currently upstream code behaves) and 
> does not proceed further.
> and on s390x we should check for vol and path, and if non of it is 
> present then instead of raising exception KCHVMSTOR0017E go ahead and 
> check for addition key dir_path. If dir_path is also not present then 
> only raise exception KCHVMSTOR0019E.
>
> Hope I make sense to you.

Yeap. That makes sense.

But what about on x86 where I have path or vol and nor dir_path? How do 
you prevent me to go to the second if and raise an exception?

The second if is not nested as you said above.

>
>>>
>>>
>>>     >           dom = VMModel.get_vm(vm_name, self.conn)
>>>     >           params['bus'] = _get_device_bus(params['type'], dom)
>>>     > -        params['format'] = 'raw'
>>>     > +
>>>     > +        if is_s390x() and params['type'] == 'disk':
>>>     > +            if 'format' not in params:
>>>     > +                raise InvalidParameter("KCHVMSTOR0020E")
>>>     > +            if 'dir_path' in params:
>>>     > +                size = params['size']
>>>     > +                name = params['name']
>>>     > +                dir_path = params.get('dir_path')
>>>     > +                params['path'] = dir_path + "/" + name
>>>     > +                if os.path.exists(params['path']):
>>>     > +                    raise InvalidParameter("KCHVMSTOR0021E",
>>>     > + {'disk_path': params['path']})
>>>     > +  create_disk_image(format_type=params['format'],
>>>     > +  path=params['path'], capacity=size)
>>>     > +        else:
>>>     > +            params['format'] = 'raw'
>>>     >
>>>     >           dev_list = [dev for dev, bus in
>>>     get_vm_disks(dom).iteritems()
>>>     >                       if bus == params['bus']]
>>>     > diff --git a/utils.py b/utils.py
>>>     > index 0fca191..7fdec02 100644
>>>     > --- a/utils.py
>>>     > +++ b/utils.py
>>>     > @@ -305,4 +305,4 @@ def create_disk_image(format_type, path,
>>>     capacity):
>>>     >       if rc != 0:
>>>     >           raise OperationFailed("KCHTMPL0035E", {'err': err})
>>>     >
>>>     > -    return
>>>     > \ No newline at end of file
>>>     > +    return
>>>
>>>     _______________________________________________
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>>>     Kimchi-devel at ovirt.org
>>>     http://lists.ovirt.org/mailman/listinfo/kimchi-devel
>>>
>>>
>>
>>
>>
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>> Kimchi-devel at ovirt.org
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>

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