[Openstack] Live Migration of VMs without shared storage

Remo Mattei Remo at Italy1.com
Tue Mar 3 05:35:10 UTC 2015


You need to make sure that you ssh between machines using the nova user not root user. 

Remo 
> On Mar 2, 2015, at 21:33, somshekar kadam <som_kadam at yahoo.co.in> wrote:
> 
> Remo, 
> I did not understand, nova can not root ?
> 
> DO I need to make user root ssh instead of a user ?
>  
> 
> Regards 
> Neelu
> 
> 
> On Monday, 2 March 2015 10:41 PM, Remo Mattei <remo at italy1.com> wrote:
> 
> 
> Make sure nova can not root. 
> 
> Remo
> 
> Inviato da iPhone ()
> 
> Il giorno 02/mar/2015, alle ore 08:21, somshekar kadam <som_kadam at yahoo.co.in <mailto:som_kadam at yahoo.co.in>> ha scritto:
> 
>> Hello John, 
>> Thanks for all your valuable inputs. 
>> I had missed these configuration. Hope these configs mentioned below will be useful for others who are trying out live migration. 
>> 
>> 1. force_config_drive = none , otherwise it was giving error. 
>> 2. allow_migrate_to_same_host = False
>> allow_resize_to_same_host = False
>> 
>> 3. set proper cpu mode as below 
>> cpu_mode = custom
>> cpu_model = Nehalem
>> virt_type = kvm
>> 
>> Now I am able to make normal migration working fine, from one host to another. 
>> 
>> When I try with live migration with block-migration, its failing for not getting proper host key verification ,, 
>> I am looking into it. I have shared keys proper I am able to ssh to-fro host nodes using passwordless ssh. 
>> no clue right now. 
>> 
>> error log 
>> ------------------
>> [[01;31mLive Migration fa       ilure: operation failed: Failed to connect to remote libvirt URI qemu+ssh://stack@celestial8/
>> system: Cannot recv data: Host key verifica       tion failed.: Connection reset by peer^[[00m
>> 
>> 
>>       on thread notification^[[00m ^[[00;33mfrom (pid=8953) thread_finished /opt/stack/nova/nova/virt/ libvirt/driver.py:5638^[[00m
>> 270370 Traceback (most recent call last):
>> 270371   File "/usr/local/lib/python2.7/ dist-packages/eventlet/hubs/ hub.py", line 457, in fire_timers
>> 270372     timer()
>> 270373   File "/usr/local/lib/python2.7/ dist-packages/eventlet/hubs/ timer.py", line 58, in __call__
>> 270374     cb(*args, **kw)
>> 270375   File "/usr/local/lib/python2.7/ dist-packages/eventlet/event. py", line 168, in _do_send
>> 270376     waiter.switch(result)
>> 270377   File "/usr/local/lib/python2.7/ dist-packages/eventlet/ greenthread.py", line 214, in main
>> 270378     result = function(*args, **kwargs)
>> 270379   File "/opt/stack/nova/nova/virt/ libvirt/driver.py", line 5435, in _live_migration_operation
>> 270380     instance=instance)
>> 270381   File "/usr/local/lib/python2.7/ dist-packages/oslo_utils/ excutils.py", line 82, in __exit__
>> 270382     six.reraise(self.type_, self.value, self.tb)
>> 270383   File "/opt/stack/nova/nova/virt/ libvirt/driver.py", line 5404, in _live_migration_operation
>> 270384     CONF.libvirt.live_migration_ bandwidth)
>> 270385   File "/usr/local/lib/python2.7/ dist-packages/eventlet/tpool. py", line 183, in doit
>> 270386     result = proxy_call(self._autowrap, f, *args, **kwargs)
>> 270387   File "/usr/local/lib/python2.7/ dist-packages/eventlet/tpool. py", line 141, in proxy_call
>> 270388     rv = execute(f, *args, **kwargs)
>> 270389   File "/usr/local/lib/python2.7/ dist-packages/eventlet/tpool. py", line 122, in execute
>> 270390     six.reraise(c, e, tb)
>> 270391   File "/usr/local/lib/python2.7/ dist-packages/eventlet/tpool. py", line 80, in tworker
>> 270392     rv = meth(*args, **kwargs)
>> 270393   File "/usr/lib/python2.7/dist- packages/libvirt.py", line 1582, in migrateToURI2
>> 270394     if ret == -1: raise libvirtError ('virDomainMigrateToURI2() failed', dom=self)
>> 270395 libvirtError: operation failed: Failed to connect to remote libvirt URI qemu+ssh://stack@celestial8/ system: Cannot recv data: Host key v       erification failed.: Connection reset by peer
>> @                                                                   
>> -----
>> 
>> 
>>  
>> 
>> Regards 
>> Neelu
>> 
>> 
>> On Friday, 27 February 2015 8:09 PM, somshekar kadam <som_kadam at yahoo.co.in <mailto:som_kadam at yahoo.co.in>> wrote:
>> 
>> 
>> Have done the same configs as mentioned in above thread links for libvirt and nova.conf. 
>>  
>> 
>> Regards 
>> Neelu
>> 
>> 
>> On Friday, 27 February 2015 8:07 PM, somshekar kadam <som_kadam at yahoo.co.in <mailto:som_kadam at yahoo.co.in>> wrote:
>> 
>> 
>> John, your patch is in the mainline now. I have tested it. Not sure what is the thing I am missing
>> I have specified cpu model none and even tried setting cpu mode custom also and model kvm64. 
>> 
>> I am getting below error on live migration. 
>> 
>> error log
>> ----
>> Remote error: libvirtError Requested operation is not valid: no CPU model specified [u’Traceback (most recent call last):\n’, u’ File “/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py”, line 142, in _dispatch_and_reply\n executo
>> Code
>> 500
>> Details
>> File “/opt/stack/nova/nova/conductor/manager.py”, line 606, in _live_migrate block_migration, disk_over_commit) File “/opt/stack/nova/nova/conductor/tasks/live_migrate.py”, line 194, in execute return task.execute() File “/opt/stack/nova/nova/conductor/tasks/live_migrate.py”, line 62, in execute self._check_requested_destination() File “/opt/stack/nova/nova/conductor/tasks/live_migrate.py”, line 100, in _check_requested_destination self._call_livem_checks_on_host(self.destination) File “/opt/stack/nova/nova/conductor/tasks/live_migrate.py”, line 142, in _call_livem_checks_on_host destination, self.block_migration, self.disk_over_commit) File “/opt/stack/nova/nova/compute/rpcapi.py”, line 391, in check_can_live_migrate_destination disk_over_commit=disk_over_commit) File “/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/client.py”, line 156, in call retry=self.retry) File “/usr/local/lib/python2.7/dist-packages/oslo_messaging/transport.py”, line 90, in _send timeout=timeout, retry=retry) File “/usr/local/lib/python2.7/dist-packages/oslo_messaging/_drivers/amqpdriver.py”, line 417, in send retry=retry) File “/usr/local/lib/python2.7/dist-packages/oslo_messaging/_drivers/amqpdriver.py”, line 408, in _send raise result
>> Created
>> --------------------
>> 
>> debug log 
>> ---------------
>> DEBUG (shell:803) Live migration of instance 477e8963-aadf-4dc7-b26f-
>> f6e9332dd33b to host celestial5 failed (HTTP 500) (Request-ID: req-7973edbc-8844-41c5-926a- 9f5e7cee62f2)
>> Traceback (most recent call last):
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/ shell.py", line 800, in main
>>     OpenStackComputeShell().main( argv)
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/ shell.py", line 730, in main
>>     args.func(self.cs, args)
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/v1_1/ shell.py", line 3001, in do_live_migration
>>     args.disk_over_commit)
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/v1_1/ servers.py", line 344, in live_migrate
>>     disk_over_commit)
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/v1_1/ servers.py", line 1124, in live_migrate
>>     'disk_over_commit': disk_over_commit})
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/v1_1/ servers.py", line 1240, in _action
>>     return self.api.client.post(url, body=body)
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/ client.py", line 490, in post
>>     return self._cs_request(url, 'POST', **kwargs)
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/ client.py", line 465, in _cs_request
>>     resp, body = self._time_request(url, method, **kwargs)
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/ client.py", line 439, in _time_request
>>     resp, body = self.request(url, method, **kwargs)
>>   File "/usr/local/lib/python2.7/ dist-packages/novaclient/ client.py", line 433, in request
>>     raise exceptions.from_response(resp, body, url, method)
>> ClientException: Live migration of instance 477e8963-aadf-4dc7-b26f- f6e9332dd33b to host celestial5 failed (HTTP 500) (Request-ID: req-7973edbc-8844-41c5-926a- 9f5e7cee62f2)
>> ERROR (ClientException): Live migration of instance 477e8963-aadf-4dc7-b26f- f6e9332dd33b to host celestial5 failed (HTTP 500) (Request-ID: req-7973edbc-8844-41c5-926a- 9f5e7cee62f2)
>> ----------------------
>> 
>> Regards 
>> Neelu
>> 
>> 
>> On Thursday, 26 February 2015 8:21 PM, John Griffith <john.griffith at solidfire.com <mailto:john.griffith at solidfire.com>> wrote:
>> 
>> 
>> 
>> 
>> On Thu, Feb 26, 2015 at 7:07 AM, somshekar kadam <som_kadam at yahoo.co.in <mailto:som_kadam at yahoo.co.in>> wrote:
>> First of all thanks for quick reply. 
>> Documentation does not mention much about Volume-backed live migration. 
>> Is it tested, I mean supported and working. 
>> I will try Block live migration as no storage is required. 
>>  
>> 
>> Regards 
>> Neelu
>> 
>> 
>> On Thursday, 26 February 2015 7:13 PM, Robert van Leeuwen <Robert.vanLeeuwen at spilgames.com <mailto:Robert.vanLeeuwen at spilgames.com>> wrote:
>> 
>> 
>> > Is the Live Migration of VMs even without shared storage supported in Openstack now.
>> > If yes is there any document for the same.
>> 
>> 
>> Wel, depends on what you call "supported".
>> Yes, it is possible. 
>> Will it always work? Probably not until you look at the bugs below.
>> They have been fixed recently but they might not be merged with the version you are running: 
>> https://bugs.launchpad.net/nova/+bug/1270825 <https://bugs.launchpad.net/nova/+bug/1270825>
>> https://bugs.launchpad.net/nova/+bug/1082414 <https://bugs.launchpad.net/nova/+bug/1082414>
>> 
>> There might be more issues but I hit the ones mentioned above.
>> Have a look at the docs to configure it:
>> http://docs.openstack.org/admin-guide-cloud/content/section_configuring-compute-migrations.html <http://docs.openstack.org/admin-guide-cloud/content/section_configuring-compute-migrations.html>
>> 
>> Cheers,
>> Robert van Leeuwen
>> 
>> 
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>> 
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>> 
>> 
>> It's dated and getting the patches backported has proven to take forever, but I did a write up and testing on this a while back [1].  Should still be accurate.
>> 
>> Thanks,
>> John
>> 
>> [1]: https://griffithscorner.wordpress.com/2014/12/08/openstack-live-migration-with-cinder-backed-instances/ <https://griffithscorner.wordpress.com/2014/12/08/openstack-live-migration-with-cinder-backed-instances/>
>> 
>> 
>> 
>> 
>> 
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