[Kimchi-devel] Kimchi migration within peers
Leonardo Augusto Guimarães Garcia
lagarcia at linux.vnet.ibm.com
Thu Oct 23 14:38:00 UTC 2014
lagarcia at br.ibm.comn 10/23/2014 08:43 AM, simonjin wrote:
>
> 在 2014年10月22日 20:28, Aline Manera 写道:
>>
>> On 10/22/2014 10:20 AM, Aline Manera wrote:
>>>
>>> On 10/22/2014 07:24 AM, simonjin wrote:
>>>> On 10/22/2014 01:48 AM, Aline Manera wrote:
>>>>>
>>>>> On 10/20/2014 12:50 AM, simonjin wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> I'm presenting here my proposal for the feature "Guest migration"
>>>>>> which
>>>>>> is expected to be implemented for Kimchi 1.4.
>>>>>>
>>>>>>
>>>>>> Description
>>>>>>
>>>>>> Migrate guest vm within peer/host discovered by Kimchi peers
>>>>>> using openSLP.
>>>>>> In the first stage 1, only do migration will be supported,
>>>>>> in stage2, migrateCancel and migrateMonitor will be supported.
>>>>>>
>>>>>> *Migration Mode: *
>>>>>> 1. Support libvirt tunnelled transport managed by direct migration.
>>>>>> 2. Only support Live migration mode.
>>>>>> 3. Only support migration over TCP
>>>>>>
>>>>>> *Migration Capability Check*
>>>>>> - Source libvirtd/client should be able to connect destination
>>>>>> libvirtd.
>>>>>> - CPU architectures compare(X86 vs PPC).
>>>>>> - No PCI device passthrough.
>>>>>> - In a shared storage pool and the pool can be access/write by
>>>>>> destination.
>>>>>>
>>>>>>
>>>>>> REST API
>>>>>>
>>>>>> Only one new REST command will be added in stage 1.
>>>>>>
>>>>>>
>>>>>> Syntax
>>>>>>
>>>>>> POST /vms//<vm-name>//migrate
>>>>>
>>>>> You will have a data object informing the destination host
>>>>>
>>>>> POST /vms/<vm-name>/migrate {host: ...}
>>>>>
>>>> ok, the json data will be {host:ip, user:username, passwd:password}
>>>>
>>>>>>
>>>>>> Parameters:
>>>>>>
>>>>>
>>>>>> in config.py.in:
>>>>>>
>>>>>> ('migration_destination_timeout', '21600',
>>>>>> 'Maximum time the destination waits for the migration
>>>>>> to finish.
>>>>>> 21600 should be enough since all the peers will be in
>>>>>> the same LAN'),
>>>>>>
>>>>>> ('migration_max_bandwidth', 'unlimited',
>>>>>> 'default in libvirt is unlimited'),
>>>>>>
>>>>>> ('migration_downtime', '500',
>>>>>> 'Maxmium allowed downtime for live migration in
>>>>>> milliseconds '
>>>>>> '(anything below 100ms is ignored) if you do not care
>>>>>> about '
>>>>>> 'liveness of migration, set to a very high value,
>>>>>> such as '
>>>>>> '600000.'),
>>>>>
>>>>> I don't think we need to allow user edits those values so there is
>>>>> no need to add them to config.py.in
>>>>>
>>>> It's better to put them in kimchi.conf to allow user to edit just
>>>> in case the migration failed due to them.
>>>>
>>>>>>
>>>>>> Return:
>>>>>>
>>>>>> An asynchronous Task with "target_uri" containing
>>>>>> "/vms/</new-vm-name/>".
>>>>>> As expected with any Task, the cloning process can be tracked by
>>>>>> checking the corresponding task's status.
>>>>>>
>>>>>> *Do_migration step:*
>>>>>> - migration source check .
>>>>>
>>>>> What kind of verification will be done?
>>>>> Storage pool and network? Guest permission settings?
>>>>>
>>>> will do *Migration Capability Check *described above*.
>>>>
>>>> *
>>>>>> - connect migration destination, guest vm config/params transfer
>>>>>> and setup.
>>>>>
>>>>> How will it be done?
>>>>> From libvirt doc, I can see different types of migration, which
>>>>> one is the best solution for Kimchi?
>>>>>
>>>>> For reference: http://libvirt.org/migration.html
>>>>>
>>>> It will be tunneled + P2P migration,
>>>> so the API will be like:
>>>> do_migrate = dom.migrateToURI2(dest, muri, None,
>>>> libvirt.VIR_MIGRATE_LIVE |
>>>> libvirt.VIR_MIGRATE_PEER2PEER |
>>>> libvirt.VIR_MIGRATE_TUNNELLED |
>>>> libvirt.VIR_MIGRATE_ABORT_ON_ERROR,
>>>> None, maxbandwidth)
>>>>
>>>>>> - migration source prepare.
>>>>>> - do actually migration.
>>>>>
>>>>> Does libvirt python API have native support for that?
>>>>>
>>>> Will wrapper the native libvirt python API and put it in a task.
>>>>>> - recover if failed.
>>>>>
>>>>> Probably, on fail, some leftovers will be on destination server.
>>>>> How will you do the clean up?
>>>> Will destroy remote vm instance on destination and resume source vm
>>>> is being paused.
>>>>> Will it be a communication between the Kimchi servers?
>>>> the migration communication will be between to libvirtd.
>>>>> What about if the destination server does not have a Kimchi setup?
>>>>>
>>>> the destination server is discovered by kimchi, which will guaranty
>>>> it has a kimchi setup.
>>>
>>> So can not I migrate my guest to a new server without Kimchi?
>>
>> What about I am migrating from Kimchi to ovirt/openstack?
>>
> Migration should be only between kimchi peers,
> there is no way to migrate to ovirt/openstack host via kimchi API.
I agree there is no way to migrate to oVirt/OpenStack. However, from our
perspective, this should not matter.
As you said on your proposal "Source libvirtd/client should be able to
connect destination libvirtd.". So, the only thing that should matter is
whether we have a libvirt running on the other side or not. This is what
we need to check (and I think libvirt API checks this for us and return
an error if it doesn't find a libvirt running on the destination). From
a migration perspective, it doesn't matter if the destination is running
Kimchi, oVirt, OpenStack or any other management tool. We should only
check if libvirt is running and, if it is running and the migration is
successful, we are good.
On the Kimchi UI, we will, of course, have an easy way to select a
Kimchi peer and migrate to it if Federation is on and other peers have
discovered but we need to give the option to the user, IMO, to select an
arbitrary IP where they know libvirt is running to migrate the VM to
that host.
Best regards,
Leonardo Garcia
>
>>>
>>>>
>>>> -Simon
>>>>>> - do finish if migration successful.
>>>>>>
>>>>>>
>>>>>> Comments are welcome!
>>>>>> --
>>>>>> Yun Tong Jin, Simon
>>>>>> Linux Technology Center, Open Virtualization project
>>>>>> IBM Systems & Technology Group
>>>>>> jinyt at cn.ibm.com, Phone: 824549654
>>>>>
>>>>
>>>>
>>>> --
>>>> Yun Tong Jin, Simon
>>>> Linux Technology Center, Open Virtualization project
>>>> IBM Systems & Technology Group
>>>> jinyt at cn.ibm.com, Phone: 824549654
>>>
>>>
>>>
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>>
>
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>
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