[Kimchi-devel] [RFC: PATCH v1] Prevent disks from being added more than once
Christy Perez
christy at linux.vnet.ibm.com
Fri Sep 26 16:09:22 UTC 2014
Thanks Royce! A few questions below...
On 09/26/2014 04:48 AM, Royce Lv wrote:
> On 2014年09月25日 06:29, Christy Perez wrote:
>> The concept of a ref count for disks had been added, but this count
>> was dependant upon the pool name for a disk. However, the pool name
>> wasn't being stored in the VM XML so it wasn't possible to retreive
>> the pool for the disk in order to update the ref count.
> Thanks for the fix, I noticed this for a while but always forget to
> document.
>
> I think use 'pool' and 'vol' is a nice way, still we need to check if
> this works well in all distros for all storage types(iscsi, logical etc)
> after all according to libvirt doc, this has been introduced in 1.0.5,
> and 'mode' attr in 1.1.1,
> not sure for powerkvm and rhel it can work.
Absolutely. That's the big reason I sent this as an RFC. I have tested
it on x86 on Fedora, and powerKVM, but only with file-based storage.
There's a lot more testing to do, and I wanted to make sure before I get
too deep into that, that no one objected to any of the changes I'd made.
>
> If we are going to adopt current way, we can just update the ref count
> when adding a new disk to vm(as it is chosen from pool),
> the def create() delete() in vmstorages.py needs to change.
> Though path is stored rather than pool in vm xml, we did a path query
> for all existent disk, to guarantee the right ref count is recorded.
> So things remaining are updating this ref count when volume's deleted
> from and added to vm.
I'm not sure I follow. It sounds like you're explaining how things
worked before my patch, but also making suggestions for what else I
might change? Can you clarify?
>
>>
>> To fix this, this patch changes the way that disks are added when
>> created in libvirt storage pools. Instead of files, they are treated
>> as volumes in pools.
>>
>> Note: Because of this modification, a small inconsistency in the API,
>> which states that the pool for a vm's "storages" is returned, is
>> corrected. The pool is returned as an empty string if the disk or
>> volume was not create from a pool (e.g. a remote ISO).
>>
>> Signed-off-by: Christy Perez <christy at linux.vnet.ibm.com>
>> ---
>> src/kimchi/model/storagevolumes.py | 13 ++++++--
>> src/kimchi/model/vmstorages.py | 68
>> +++++++++++++++++++++++++++++++++++---
>> src/kimchi/vmdisks.py | 33 ++++++++++++++----
>> src/kimchi/vmtemplate.py | 41 ++++++++++++++++-------
>> 4 files changed, 129 insertions(+), 26 deletions(-)
>>
>> diff --git a/src/kimchi/model/storagevolumes.py
>> b/src/kimchi/model/storagevolumes.py
>> index f9f226f..af97748 100644
>> --- a/src/kimchi/model/storagevolumes.py
>> +++ b/src/kimchi/model/storagevolumes.py
>> @@ -249,19 +249,26 @@ def _get_ref_cnt(self, pool, name, path):
>> try:
>> ref_cnt = session.get('storagevolume',
>> vol_id)['ref_cnt']
>> except NotFoundError:
>> + kimchi_log.info('Volume %s not found in obj
>> store.' % vol_id)
>> # Fix storage volume created outside kimchi scope
>> ref_cnt = 0
>> - # try to find this volume in exsisted vm
>> + # try to find this volume in exsisting vm
>> vms = VMsModel.get_vms(self.conn)
>> for vm in vms:
>> dom = VMModel.get_vm(vm, self.conn)
>> storages = get_vm_disk_list(dom)
>> for disk in storages:
>> - d_info = get_vm_disk(dom, disk)
>> + d_info = get_vm_disk(dom, disk, self.conn)
>> if path == d_info['path']:
>> ref_cnt = ref_cnt + 1
>> - session.store('storagevolume', vol_id,
>> + try:
>> + session.store('storagevolume', vol_id,
>> {'ref_cnt': ref_cnt})
>> + except Exception as e:
>> + # Just log an error if the obj store fails:
>> + kimchi_log.warning('Unable to store storage
>> volume id in '
>> + 'objectstore due error: %s', e.message)
>> +
>> except Exception as e:
>> # This exception is going to catch errors returned by
>> 'with',
>> # specially ones generated by 'session.store'. It is
>> outside
>> diff --git a/src/kimchi/model/vmstorages.py
>> b/src/kimchi/model/vmstorages.py
>> index 4d6c0b2..1b2c0fe 100644
>> --- a/src/kimchi/model/vmstorages.py
>> +++ b/src/kimchi/model/vmstorages.py
>> @@ -32,7 +32,7 @@
>> from kimchi.model.vms import DOM_STATE_MAP, VMModel
>> from kimchi.model.storagevolumes import StorageVolumeModel
>> from kimchi.model.utils import get_vm_config_flag
>> -from kimchi.utils import check_url_path
>> +from kimchi.utils import check_url_path, kimchi_log
>> from kimchi.osinfo import lookup
>> from kimchi.vmdisks import get_device_xml, get_vm_disk,
>> get_vm_disk_list
>> from kimchi.vmdisks import DEV_TYPE_SRC_ATTR_MAP
>> @@ -73,6 +73,11 @@ def _get_storage_xml(params, ignore_source=False):
>> source = E.source(protocol=output.scheme, name=output.path)
>> source.append(host)
>> disk.append(source)
>> + elif src_type == 'volume':
>> + source = E.source()
>> + source.set('pool', params.get('pool'))
>> + source.set('volume', params.get('vol'))
>> + disk.append(source)
>> else:
>> # Fixing source attribute
>> source = E.source()
>> @@ -138,6 +143,8 @@ def create(self, vm_name, params):
>> # Path will never be blank due to API.json verification.
>> # There is no need to cover this case here.
>> params['format'] = 'raw'
>> + vol_info = None
>> + vol_store_name = None
>> if not ('vol' in params) ^ ('path' in params):
>> raise InvalidParameter("KCHVMSTOR0017E")
>> if params.get('vol'):
>> @@ -146,6 +153,7 @@ def create(self, vm_name, params):
>> vol_info = StorageVolumeModel(
>> conn=self.conn,
>> objstore=self.objstore).lookup(pool, params['vol'])
>> + vol_store_name = '%s:%s' % (pool, params['vol'])
>> except KeyError:
>> raise InvalidParameter("KCHVMSTOR0012E")
>> except Exception as e:
>> @@ -158,6 +166,10 @@ def create(self, vm_name, params):
>> params['format'] = vol_info['format']
>> params['path'] = vol_info['path']
>> params['src_type'] = _check_path(params['path'])
>> + if params['src_type'] is 'file' and params.get('pool') and \
> I think if it is 'block' probably we still want to use 'volume'
I'll look into that. Thanks.
>> + params.get('vol'):
>> + params['src_type'] = 'volume'
>> + # change from 'file' to volume if in a pool ^^
>> if (params['bus'] not in HOTPLUG_TYPE
>> and DOM_STATE_MAP[dom.info()[0]] != 'shutoff'):
>> raise InvalidOperation('KCHVMSTOR0011E')
>> @@ -171,6 +183,16 @@ def create(self, vm_name, params):
>> dom.attachDeviceFlags(dev_xml, get_vm_config_flag(dom,
>> 'all'))
>> except Exception as e:
>> raise OperationFailed("KCHVMSTOR0008E", {'error':
>> e.message})
>> +
>> + try:
> I suggest we wrap a helper function to update ref_cnt rather than spread
> this code everywhere.
Same. Thanks.
>> + new_ref_cnt = vol_info['ref_cnt'] + 1
>> + with self.objstore as session:
>> + session.store('storagevolume', vol_store_name,
>> {'ref_cnt': new_ref_cnt})
>> + except Exception as e:
>> + # Just log an error if the obj store fails:
>> + kimchi_log.warning('Unable to store storage volume id in '
>> + 'objectstore due error: %s', e.message)
>> +
>> return params['dev']
>>
>> def _get_storage_device_name(self, vm_name, params):
>> @@ -192,25 +214,41 @@ def get_list(self, vm_name):
>> dom = VMModel.get_vm(vm_name, self.conn)
>> return get_vm_disk_list(dom)
>>
>> -
>> class VMStorageModel(object):
>> def __init__(self, **kargs):
>> self.conn = kargs['conn']
>> + self.objstore = kargs['objstore']
>>
>> def lookup(self, vm_name, dev_name):
>> # Retrieve disk xml and format return dict
>> dom = VMModel.get_vm(vm_name, self.conn)
>> - return get_vm_disk(dom, dev_name)
>> + disk = get_vm_disk(dom, dev_name, self.conn)
>> + # Also include the pool and volume
>> + pool_name = ''
>> + vol_name = ''
>> + try:
>> + pool_name = disk.get('pool')
>> + vol_name = disk.get('volume')
>> + except Exception as e:
>> + kimchi_log.warning('VMDisk lookup error: %s' % e.message)
>> +
>> + disk['pool'] = pool_name
>> + disk['volume'] = vol_name
>> + return disk
>>
>> def delete(self, vm_name, dev_name):
>> # Get storage device xml
>> dom = VMModel.get_vm(vm_name, self.conn)
>> + disk_info = None
>> + disk_xml = None
>> + pool_name = ''
>> + vol_name = ''
>> try:
>> - bus_type = self.lookup(vm_name, dev_name)['bus']
>> + disk_info = self.lookup(vm_name, dev_name)
>> + bus_type = disk_info['bus']
>> except NotFoundError:
>> raise
>>
>> - dom = VMModel.get_vm(vm_name, self.conn)
>> if (bus_type not in HOTPLUG_TYPE and
>> DOM_STATE_MAP[dom.info()[0]] != 'shutoff'):
>> raise InvalidOperation('KCHVMSTOR0011E')
>> @@ -224,10 +262,30 @@ def delete(self, vm_name, dev_name):
>> except Exception as e:
>> raise OperationFailed("KCHVMSTOR0010E", {'error':
>> e.message})
>>
>> + # Get the pool and vol of a disk so we can
>> + # decrement its ref_cnt in the obj store
>> + pool_name = disk_info.get('pool')
>> + vol_name = disk_info.get('volume')
>> +
>> + if(pool_name and vol_name):
>> + try:
>> + vol_id = '%s:%s' % (pool_name, vol_name)
>> + with self.objstore as session:
>> + vol = session.get('storagevolume', vol_id)
>> + if vol:
>> + ref_cnt = vol['ref_cnt']
>> + if ref_cnt > 0:
>> + ref_cnt = ref_cnt - 1
>> + session.store('storagevolume', vol_id,
>> {'ref_cnt': ref_cnt})
>> + except Exception as e:
>> + kimchi_log.warning('Unable to decrement volume ref
>> count due to %s.'
>> + % e.message)
>> +
>> def update(self, vm_name, dev_name, params):
>> path = params.get('path')
>> if path and len(path) != 0:
>> params['src_type'] = _check_path(path)
>> + # change from 'file' to 'volume' if pool ^^
>> ignore_source = False
>> else:
>> params['src_type'] = 'file'
>> diff --git a/src/kimchi/vmdisks.py b/src/kimchi/vmdisks.py
>> index 6012ada..185a499 100644
>> --- a/src/kimchi/vmdisks.py
>> +++ b/src/kimchi/vmdisks.py
>> @@ -17,6 +17,8 @@
>> # 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 libvirt
>> +import os
>> from lxml import objectify
>>
>> from kimchi.exception import NotFoundError
>> @@ -34,37 +36,56 @@ def get_device_xml(dom, dev_name):
>> return None
>> return disk[0]
>>
>> +def get_pool_xml(conn, pool_name):
>> + conn = conn.get()
>> + return objectify.fromstring(conn.\
>> + storagePoolLookupByName(pool_name).XMLDesc(0))
>>
>> -def get_vm_disk(dom, dev_name):
>> +def get_vm_disk(dom, dev_name, conn):
>> # Retrieve disk xml and format return dict
>> disk = get_device_xml(dom, dev_name)
>> if disk is None:
>> raise NotFoundError(
>> "KCHVMSTOR0007E",
>> {'dev_name': dev_name, 'vm_name': dom.name()})
>> - path = ""
>> + path = ''
>> dev_bus = 'ide'
>> + pool_name = ''
>> + vol_name = ''
>> try:
>> source = disk.source
>> if source is not None:
>> - src_type = disk.attrib['type']
>> + src_type = disk.get('type')
>> if src_type == 'network':
>> host = source.host
>> path = (source.attrib['protocol'] + '://' +
>> host.attrib['name'] + ':' +
>> host.attrib['port'] + source.attrib['name'])
>> + elif src_type == 'volume':
>> + pool_name = disk.source.get('pool')
>> + pool = get_pool_xml(conn, pool_name)
>> + pool_path = str(pool.target.path)
>> + vol_name = disk.source.attrib['volume']
>> + path = os.path.join(pool_path, vol_name)
>> else:
>> path = source.attrib[DEV_TYPE_SRC_ATTR_MAP[src_type]]
>> # Retrieve storage bus type
>> dev_bus = disk.target.attrib['bus']
>> - except:
>> - pass
>> + except Exception as e:
>> + kimchi_log.warning("get_vm_disk exception: %s " % e.message)
>> +
>> dev_type = disk.attrib['device']
>> +
>> + # Pool and volume may be empty strings, if the user passed a disk
>> name.
>> + # If the disk was from a storage pool, let's use that so we can
>> keep track
>> + # of its ref_cnt in the objects store.
>> return {'dev': dev_name,
>> 'type': dev_type,
>> 'path': path,
>> 'format': disk.driver.attrib['type'],
>> - 'bus': dev_bus}
>> + 'bus': dev_bus,
>> + 'pool': pool_name,
>> + 'volume': vol_name}
>>
>>
>> def get_vm_disk_list(dom):
>> diff --git a/src/kimchi/vmtemplate.py b/src/kimchi/vmtemplate.py
>> index 5f22db9..1940911 100644
>> --- a/src/kimchi/vmtemplate.py
>> +++ b/src/kimchi/vmtemplate.py
>> @@ -187,24 +187,41 @@ def _get_cdrom_xml(self,
>> libvirt_stream_protocols, qemu_stream_dns):
>> return network_file % (params)
>>
>> def _get_disks_xml(self, vm_uuid):
>> - storage_path = self._get_storage_path()
>> + def TYPE(v):
>> + return {'type': v}
>> +
>> + #storage_path = self._get_storage_path()
>> + _pool = pool_name_from_uri(self.info['storagepool'])
>> ret = ""
>> for i, disk in enumerate(self.info['disks']):
>> index = disk.get('index', i)
>> - volume = "%s-%s.img" % (vm_uuid, index)
>> - src = os.path.join(storage_path, volume)
>> + _volume = "%s-%s.img" % (vm_uuid, index)
>> + #src = os.path.join(storage_path, volume)
>> dev = "%s%s" % (self._bus_to_dev[self.info['disk_bus']],
>> string.lowercase[index])
>> fmt = 'raw' if self._get_storage_type() in ['logical']
>> else 'qcow2'
>> - params = {'src': src, 'dev': dev, 'bus':
>> self.info['disk_bus'],
>> - 'type': fmt}
>> - ret += """
>> - <disk type='file' device='disk'>
>> - <driver name='qemu' type='%(type)s' cache='none'/>
>> - <source file='%(src)s' />
>> - <target dev='%(dev)s' bus='%(bus)s' />
>> - </disk>
>> - """ % params
>> + #params = {'src': src, 'dev': dev, 'bus':
>> self.info['disk_bus'],
>> + # 'type': fmt}
>> + #ret += """
>> + #<disk type='file' device='disk'>
>> + # <driver name='qemu' type='%(type)s' cache='none'/>
>> + # <source file='%(src)s' />
>> + # <target dev='%(dev)s' bus='%(bus)s' />
>> + #</disk>
>> + #""" % params
>> +
>> + # Instead do:
>> + #<disk type='volume'>
>> + # <driver name='qemu' type='%(type)s' cache='none'/>
>> + # <source pool='%(pool)s' volume='%(volume)s' />
>> + # <target dev='%(dev)s' bus='%(bus)s />
>> + #</disk>
>> + disk = E.disk(
>> + E.driver(TYPE(fmt), name='qemu', cache='none'),
>> + E.source(pool=_pool, volume=_volume),
>> + E.target(dev=dev, bus=self.info['disk_bus']),
>> + TYPE('volume'))
>> + ret += etree.tostring(disk)
>> return ret
>>
>> def _get_graphics_xml(self, params):
>
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