[Kimchi-devel] [v6 1/1] Virtual machine migration
simonjin
simonjin at linux.vnet.ibm.com
Mon Dec 22 05:08:21 UTC 2014
在 2014年12月16日 15:08, Royce Lv 写道:
> On 2014年12月16日 10:39, simonjin at linux.vnet.ibm.com wrote:
>> From: Simon Jin<simonjin at linux.vnet.ibm.com>
>>
>> v6-v5:Fix pep8, delete migratation finish func.
>> Signed-off-by: Simon Jin<simonjin at linux.vnet.ibm.com>
>> ---
>> docs/API.md | 5 ++
>> src/kimchi/control/vms.py | 3 +
>> src/kimchi/i18n.py | 8 +++
>> src/kimchi/model/vms.py | 166 +++++++++++++++++++++++++++++++++++++++++++++-
>> 4 files changed, 180 insertions(+), 2 deletions(-)
>>
>> diff --git a/docs/API.md b/docs/API.md
>> index 210a036..4408764 100644
>> --- a/docs/API.md
>> +++ b/docs/API.md
>> @@ -132,6 +132,11 @@ the following general conventions:
>> It emulates the power reset button on a machine. Note that there is a
>> risk of data loss caused by reset without the guest OS shutdown.
>> * connect: Prepare the connection for spice or vnc
>> +* migrate: Migrate a virtual machine to a remote server, only support live mode without block migration.
>> + * remoteHost: IP address or hostname of the remote server.
>> + * user: User of the remote server.
>> + * passwd: Passwd of user on remote server.
>> + * secure: Migrate in P2P secure tunel mode.(optional)
> Can we add this func to API.json so that parameters can be checked?
Will do.
>> * clone: Create a new VM identical to this VM. The new VM's name, UUID and
>> network MAC addresses will be generated automatically. Each existing
>> diff --git a/src/kimchi/control/vms.py b/src/kimchi/control/vms.py
>> index a1589ef..3638b3a 100644
>> --- a/src/kimchi/control/vms.py
>> +++ b/src/kimchi/control/vms.py
>> @@ -42,6 +42,9 @@ class VM(Resource):
>> for ident, node in sub_nodes.items():
>> setattr(self, ident, node(model, self.ident))
>> self.start = self.generate_action_handler('start')
>> + self.migrate = self.generate_action_handler_task('migrate',
>> + ['remoteHost', 'user',
>> + 'passwd', 'secure'])
>> self.poweroff = self.generate_action_handler('poweroff')
>> self.shutdown = self.generate_action_handler('shutdown')
>> self.reset = self.generate_action_handler('reset')
>> diff --git a/src/kimchi/i18n.py b/src/kimchi/i18n.py
>> index e3a051c..81a6dbb 100644
>> --- a/src/kimchi/i18n.py
>> +++ b/src/kimchi/i18n.py
>> @@ -107,6 +107,14 @@ messages = {
>> "KCHVM0033E": _("Virtual machine '%(name)s' must be stopped before cloning it."),
>> "KCHVM0034E": _("Insufficient disk space to clone virtual machine '%(name)s'"),
>> "KCHVM0035E": _("Unable to clone VM '%(name)s'. Details: %(err)s"),
>> + "KCHVM0036E": _("Migrate %(name)s to localhost %(remoteHost)s is not allowed."),
>> + "KCHVM0037E": _("vm %(name)s is already in migrating, can not perform migrate on it again."),
>> + "KCHVM0038E": _("Can't migrate vm %(name)s on Hypervisor arch %(srcarch)s.to a different Hypervisor arch %(destarch)s."),
>> + "KCHVM0039E": _("Can't migrate %(name)s from %(srchyp)s to a different Hypervisor type %(desthyp)s."),
>> + "KCHVM0040E": _("Can't migrate vm %(name)s, vm has passthrough device %(hostdevs)s."),
>> + "KCHVM0041E": _("Can not migrate vm %(name)s when its in %(state)s state."),
>> + "KCHVM0042E": _("Failed Migrate vm %(name)s due error: %(err)s"),
>> + "KCHVM0043E": _("Failed to destroy vm %(name)s from migration recover. Details: %(err)s"),
>>
>> "KCHVMHDEV0001E": _("VM %(vmid)s does not contain directly assigned host device %(dev_name)s."),
>> "KCHVMHDEV0002E": _("The host device %(dev_name)s is not allowed to directly assign to VM."),
>> diff --git a/src/kimchi/model/vms.py b/src/kimchi/model/vms.py
>> index 3aa1145..023bd10 100644
>> --- a/src/kimchi/model/vms.py
>> +++ b/src/kimchi/model/vms.py
>> @@ -33,9 +33,10 @@ from cherrypy.process.plugins import BackgroundTask
>> from kimchi import model, vnc
>> from kimchi.config import READONLY_POOL_TYPE, config
>> from kimchi.exception import InvalidOperation, InvalidParameter
>> -from kimchi.exception import NotFoundError, OperationFailed
>> +from kimchi.exception import NotFoundError, OperationFailed, KimchiException
> Why do we need to introduce general error KimchiException?
/ def _recover(self, name, destconn, cb):
"""Recover from a failed migration.
Arguments:
"cb": A callback function to signal the Task's progress.
"name": Name of the virtual machine to be migrated.
"destConn": A LibvirtConnection to destination server.
"""
try:
destvm = self.get_vm(name, destconn)
except KimchiException as e:
if type(e) == NotFoundError:
return/
self.get_vm will raise a kimchiExecption when no vm found, and here i
need catch it and make _recover
return since the vm is not exiting on remote server, no need more action
in recover.
>> from kimchi.model.config import CapabilitiesModel
>> -from kimchi.model.tasks import TaskModel
>> +from kimchi.model.libvirtconnection import LibvirtConnection
>> +from kimchi.model.tasks import TaskModel, TasksModel
>> from kimchi.model.templates import TemplateModel
>> from kimchi.model.utils import get_vm_name
>> from kimchi.model.utils import get_metadata_node
>> @@ -268,6 +269,7 @@ class VMModel(object):
>> self.groups = import_class('kimchi.model.groups.GroupsModel')(**kargs)
>> self.vms = VMsModel(**kargs)
>> self.task = TaskModel(**kargs)
>> + self.tasks = TasksModel(**kargs)
>> self.storagepool = model.storagepools.StoragePoolModel(**kargs)
>> self.storagevolume = model.storagevolumes.StorageVolumeModel(**kargs)
>> self.storagevolumes = model.storagevolumes.StorageVolumesModel(**kargs)
>> @@ -850,6 +852,166 @@ class VMModel(object):
>> raise OperationFailed("KCHVM0019E",
>> {'name': name, 'err': e.get_error_message()})
>>
>> + def _preCheck(self, name, destConn, remoteHost):
>> + """Pre check before migration"""
>> +
>> + kimchi_log.debug('precheck migrate %s' % name)
>> + _destConn = destConn.get()
>> + if remoteHost in ['localhost', '127.0.0.1']:
>> + kimchi_log.debug('vm %s Can not migrate to localhost.' % name)
>> + raise OperationFailed("KCHVM0036E", {'name': name,
>> + 'remoteHost': remoteHost})
>> + # check if the vm already in migration
>> + try:
>> + alltasks = self.tasks.get_list()
>> + for taskid in alltasks:
>> + taskobj = self.task.lookup(taskid)
>> + if taskobj['target_uri'] == "/vms/%s/migrate" % name \
>> + and taskobj['status'] == "running":
> We need to abstract a helper function for this because we use
> target_uri filtering a lot.
Will do.
> Besides, I think we need a lock here rather than just check the task
> id, because we enter this part, we are ahead of the actual creation of
> tasks. we may have 2 migrations pass this check before both running to
> "add_task" line.
Migration on UI will be disabled after one migration started.
> Or do we have a libvirt/qemu lock to leverage so that we can probe its
> status?
libvirt doesn't have a field for vm migration status.
>> + kimchi_log.debug('vm %s is already in migrating.' % name)
>> + raise OperationFailed("KCHVM0037E", {'name': name})
>> + except NotFoundError:
>> + kimchi_log.debug('No previous migrate on vm %s.' % name)
>> +
>> + srcarch = self.conn.get().getInfo()[0]
>> + destarch = _destConn.getInfo()[0]
>> + if srcarch != destarch:
>> + kimchi_log.debug('vm %s can not migrate to different arch server.'
>> + % (name, destarch))
>> + raise OperationFailed("KCHVM0038E", {'name': name,
>> + 'srcarch': srcarch,
>> + 'destarch': destarch})
> AFAIK, these requirements seem not enough to guarantee a
> migration,(see http://wiki.libvirt.org/page/VM_lifecycle#Migration)
>
> Requirements for migration:
>
> * Shared storage accessible under same paths and locations,e.g.
> iSCSI, NFS, etc.
> * Exactly the same versions of hypervisor software on both physical
> hosts
> * Same network configuration.
> * Same CPUs or better. The CPUs must be from the same vendor and the
> CPU flags on the destination host must be superset of CPU flags on
> the source host.
>
The above check already covered by libvirt/qemu, shall we leave them to
libvirt/qemu like virt-manage/openstack does ?
>
>> + srchyp = self.conn.get().getType()
>> + desthyp = _destConn.getType()
>> + if srchyp != desthyp:
>> + kimchi_log.debug('vm %s can not migrate to a different hypervisor'
>> + % name)
>> + raise OperationFailed("KCHVM0039E", {'name': name,
>> + 'srchyp': srchyp,
>> + 'desthyp': desthyp})
>> +
>> + # model.host import DOM_STATE_MAP, vmhostdevs import host,
>> + # to void loop import DOM_STATE_MAP, move import VMHostDevsModel here
>> + from kimchi.model.vmhostdevs import VMHostDevsModel
>> + # check if there is any passthrough devices belong to this vm
>> + vmhostdevs = VMHostDevsModel(conn=self.conn)
>> + hostdevs = vmhostdevs.get_list(name)
>> + if hostdevs:
>> + raise OperationFailed("KCHVM0040E", {'name': name,
>> + 'hostdevs': hostdevs})
>> +
>> + @staticmethod
>> + def _getRemoteConn(remoteHost, user, passwd, transport='ssh'):
>> + """open destination connect to migrate"""
>> +
>> + duri = 'qemu+%s://%s@%s/system' % (transport, user, remoteHost)
>> + conn = LibvirtConnection(duri)
>> + return conn
>> +
>> + def _do_migrate(self, cb, params):
>> + """Asynchronous function which performs the migrate operation.
>> +
>> + Arguments:
>> + cb -- A callback function to signal the Task's progress.
>> + params -- A dict with the following values:
>> + "name": Name of the virtual machine to be migrated.
>> + "destConn": A LibvirtConnection to destination server.
>> + "remoteHost": The migration destination server.
>> + "secure": Migrate in P2P secure tunel mode.(optional)
>> + """
>> +
>> + name = params['name'].decode('utf-8')
>> + destConn = params['destConn']
>> + remoteHost = params['remoteHost']
>> + secure = params['secure']
>> + _destConn = destConn.get()
> We can put the destConn.get() to function to _getRemoteConn to avoid
> duplicate code.
_getRemoteConn will return a LibvirtConnection, here we need to get a
libvirt.virConnect from LibvirtConnection.
-Simon
>> +
>> + cb('starting a migration')
>> + kimchi_log.debug('migrate %s start' % name)
>> + dom = self.get_vm(name, self.conn)
>> + flag = 0
>> + if secure:
>> + flag |= (libvirt.VIR_MIGRATE_PEER2PEER |
>> + libvirt.VIR_MIGRATE_TUNNELLED)
>> +
>> + state = DOM_STATE_MAP[dom.info()[0]]
>> + if state in ['running', 'paused']:
>> + flag |= libvirt.VIR_MIGRATE_LIVE
>> + elif state == 'shutoff':
>> + flag |= (libvirt.VIR_MIGRATE_OFFLINE |
>> + libvirt.VIR_MIGRATE_PERSIST_DEST)
>> + else:
>> + kimchi_log.debug('Can not migrate vm %s when its in %s.'
>> + % (name, state))
>> + raise OperationFailed("KCHVM0041E", {'name': name,
>> + 'state': state})
>> + try:
>> + dom.migrate(_destConn, flag, None, None, 0)
>> + except libvirt.libvirtError as e:
>> + kimchi_log.error('migrate %s to %s failed' % (name, remoteHost))
>> + self._recover(name, destConn, cb)
>> + kimchi_log.debug('finish migrate %s' % name)
>> + cb('Migrate finished', False)
>> + raise OperationFailed('KCHVM0042E', {'err': e.message,
>> + 'name': name})
>> + kimchi_log.debug('finish migrate %s' % name)
>> + cb('Migrate finished', True)
>> +
>> + def migrate(self, name, remoteHost, user, passwd=None, secure=False):
>> + """Migrate a virtual machine to a remote server.
>> +
>> + Arguments:
>> + name -- The name of the virtual machine to be migrated.
>> + remoteHost -- Remote server that the VM will be migrated to.
>> + user -- Login user on remote server,prefer root.
>> + passwd -- The password of the user on remote server,
>> + if the local server
>> + has ssk key exchanged, then this param can be NULL.
>> + secure -- Migrate in P2P secure tunel mode.(optional)
>> +
>> + Return:
>> + A Task running the clone operation.
>> + """
>> + name = name.decode('utf-8')
>> + remoteHost = remoteHost.decode('utf-8')
>> + user = user.decode('utf-8')
>> +
>> + destConn = self._getRemoteConn(remoteHost, user, passwd)
>> + self._preCheck(name, destConn, remoteHost)
>> +
>> + params = {'name': name,
>> + 'destConn': destConn,
>> + 'remoteHost': remoteHost,
>> + 'secure': secure}
>> + task_id = add_task('/vms/%s/migrate' % name, self._do_migrate,
>> + self.objstore, params)
>> +
>> + return self.task.lookup(task_id)
>> +
>> + def _recover(self, name, destconn, cb):
>> + """Recover from a failed migration.
>> +
>> + Arguments:
>> + "cb": A callback function to signal the Task's progress.
>> + "name": Name of the virtual machine to be migrated.
>> + "destConn": A LibvirtConnection to destination server.
>> + """
>> + try:
>> + destvm = self.get_vm(name, destconn)
>> + except KimchiException as e:
>> + if type(e) == NotFoundError:
>> + return
>> +
>> + cb('recover from a failed migration', False)
>> + kimchi_log.debug('recover from a failed migrate %s' % name)
>> + try:
>> + destvm.destroy()
>> + kimchi_log.error("Failed to destory migrate vm %s on \
>> + destination server" % name)
>> + except libvirt.libvirtError as e:
>> + raise OperationFailed('KCHVM0043E', {'name': name,
>> + 'err': e.message})
>> +
>> def poweroff(self, name):
>> dom = self.get_vm(name, self.conn)
>> try:
>
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