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Bug 842115 - - 3.1 - beta3 - [vdsm] Migration fails as both source and destination shares the same UUID
Summary: - 3.1 - beta3 - [vdsm] Migration fails as both source and destination shares ...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: vdsm
Version: 6.3
Hardware: Unspecified
OS: Unspecified
unspecified
urgent
Target Milestone: rc
: 6.3
Assignee: Yaniv Bronhaim
QA Contact: Barak Dagan
URL:
Whiteboard: virt
: 760087 (view as bug list)
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-07-22 08:48 UTC by Ilanit Stein
Modified: 2022-07-09 05:37 UTC (History)
18 users (show)

Fixed In Version: vdsm-4.9.6-31.0
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2012-12-04 19:03:10 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2012:1508 0 normal SHIPPED_LIVE Important: rhev-3.1.0 vdsm security, bug fix, and enhancement update 2012-12-04 23:48:05 UTC

Description Ilanit Stein 2012-07-22 08:48:38 UTC 
Description of problem:

There is a logical problem having VM migrating to original host, in case migration to a 2nd host fail. 

How reproducible:
always
 
Steps to Reproduce:
1.Setup with 2 active hosts.
2. Make sure that VMs migration will fail to 2nd host,
3. see that migration to the original host starts in vdsm log, and fail of course
  
Actual results:

Migration to original host

From vdsm log:
Thread-1758::ERROR::2012-07-21 12:41:38,261::vm::176::vm.Vm::(_recover) vmId=`b373f0fd-c1d8-423b-ba1e-7372ce65a2d3`::internal error Attempt to migrate guest to the same host 44454c4c-4300-1046-805a-c2c04f37354a
Thread-1756::ERROR::2012-07-21 12:41:38,332::vm::240::vm.Vm::(run) vmId=`703bf2f9-9cbd-422b-8022-5addcd21c752`::Failed to migrate
Traceback (most recent call last):
  File "/usr/share/vdsm/vm.py", line 223, in run
    self._startUnderlyingMigration()
  File "/usr/share/vdsm/libvirtvm.py", line 451, in _startUnderlyingMigration
    None, maxBandwidth)
  File "/usr/share/vdsm/libvirtvm.py", line 491, in f
    ret = attr(*args, **kwargs)
  File "/usr/lib64/python2.6/site-packages/vdsm/libvirtconnection.py", line 82, in wrapper
    ret = f(*args, **kwargs)
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 1104, in migrateToURI2
    if ret == -1: raise libvirtError ('virDomainMigrateToURI2() failed', dom=self)


For logs of engine\2 hosts vdsm please see:
==========================================
https://bugzilla.redhat.com/show_bug.cgi?id=840553
Comment 1 Oded Ramraz 2012-07-23 20:45:47 UTC 
I noticed a weird thing:
Both source and destination hosts have the same uuid suffix from some reason:

[root@cinteg14 ~]# vdsClient -s 0 getVdsCaps | grep -i uuid
        networks = {'rhevm': {'addr': '10.35.148.66', 'cfg': {'IPV6INIT': 'yes', 'DHCP_HOSTNAME': 'cinteg14.ci.lab.tlv.redhat.com', 'HOSTNAME': 'cinteg14.ci.lab.tlv.redhat.com', 'MTU': '1500', 'DELAY': '0', 'NM_CONTROLLED': 'no', 'BOOTPROTO': 'dhcp', 'DEVICE': 'rhevm', 'TYPE': 'Bridge', 'ONBOOT': 'yes', 'UUID': '6939f13e-47bf-47ae-b90a-62b8d1c40ba8'}, 'mtu': '1500', 'netmask': '255.255.252.0', 'stp': 'off', 'bridged': True, 'gateway': '10.35.151.254', 'ports': ['em1', 'vnet0', 'vnet1', 'vnet2']}}
        uuid = 4C4C4544-0043-4610-805A-C2C04F37354A_00:26:6C:FF:B2:64



[root@cinteg16 ~]# vdsClient -s 0 getVdsCaps | grep -i uuid
        networks = {'rhevm': {'addr': '10.35.148.70', 'cfg': {'IPV6INIT': 'yes', 'DHCP_HOSTNAME': 'cinteg16.ci.lab.tlv.redhat.com', 'HOSTNAME': 'cinteg16.ci.lab.tlv.redhat.com', 'MTU': '1500', 'DELAY': '0', 'NM_CONTROLLED': 'no', 'BOOTPROTO': 'dhcp', 'DEVICE': 'rhevm', 'TYPE': 'Bridge', 'ONBOOT': 'yes', 'UUID': 'a24ed2b9-8ed4-49da-96e9-8195dd92468f'}, 'mtu': '1500', 'netmask': '255.255.252.0', 'stp': 'off', 'bridged': True, 'gateway': '10.35.151.254', 'ports': ['em1', 'vnet0', 'vnet1']}}
        uuid = 4C4C4544-0043-4610-805A-C2C04F37354A_00:26:6C:FF:B6:44

I see that in /usr/lib64/python2.6/site-packages/vdsm/utils.py the uuid computed as follows:
p = subprocess.Popen([constants.EXT_SUDO,
                              constants.EXT_DMIDECODE, "-s", "system-uuid"],

Is it possible that two hosts gets the same uuid ?
Comment 2 Yaniv Kaul 2012-07-23 22:11:52 UTC 
(In reply to comment #1)
> I noticed a weird thing:
> Both source and destination hosts have the same uuid suffix from some reason:
> 
> [root@cinteg14 ~]# vdsClient -s 0 getVdsCaps | grep -i uuid
>         networks = {'rhevm': {'addr': '10.35.148.66', 'cfg': {'IPV6INIT':
> 'yes', 'DHCP_HOSTNAME': 'cinteg14.ci.lab.tlv.redhat.com', 'HOSTNAME':
> 'cinteg14.ci.lab.tlv.redhat.com', 'MTU': '1500', 'DELAY': '0',
> 'NM_CONTROLLED': 'no', 'BOOTPROTO': 'dhcp', 'DEVICE': 'rhevm', 'TYPE':
> 'Bridge', 'ONBOOT': 'yes', 'UUID': '6939f13e-47bf-47ae-b90a-62b8d1c40ba8'},
> 'mtu': '1500', 'netmask': '255.255.252.0', 'stp': 'off', 'bridged': True,
> 'gateway': '10.35.151.254', 'ports': ['em1', 'vnet0', 'vnet1', 'vnet2']}}
>         uuid = 4C4C4544-0043-4610-805A-C2C04F37354A_00:26:6C:FF:B2:64
> 
> 
> 
> [root@cinteg16 ~]# vdsClient -s 0 getVdsCaps | grep -i uuid
>         networks = {'rhevm': {'addr': '10.35.148.70', 'cfg': {'IPV6INIT':
> 'yes', 'DHCP_HOSTNAME': 'cinteg16.ci.lab.tlv.redhat.com', 'HOSTNAME':
> 'cinteg16.ci.lab.tlv.redhat.com', 'MTU': '1500', 'DELAY': '0',
> 'NM_CONTROLLED': 'no', 'BOOTPROTO': 'dhcp', 'DEVICE': 'rhevm', 'TYPE':
> 'Bridge', 'ONBOOT': 'yes', 'UUID': 'a24ed2b9-8ed4-49da-96e9-8195dd92468f'},
> 'mtu': '1500', 'netmask': '255.255.252.0', 'stp': 'off', 'bridged': True,
> 'gateway': '10.35.151.254', 'ports': ['em1', 'vnet0', 'vnet1']}}
>         uuid = 4C4C4544-0043-4610-805A-C2C04F37354A_00:26:6C:FF:B6:44
> 
> I see that in /usr/lib64/python2.6/site-packages/vdsm/utils.py the uuid
> computed as follows:
> p = subprocess.Popen([constants.EXT_SUDO,
>                               constants.EXT_DMIDECODE, "-s", "system-uuid"],
> 
> Is it possible that two hosts gets the same uuid ?
Indeed:
[root@cinteg16 ~]# dmidecode |grep UUID
	UUID: 4C4C4544-0043-4610-805A-C2C04F37354A
[root@cinteg16 ~]# ssh root@cinteg14 "dmidecode |grep UUID"
root@cinteg14's password: 
	UUID: 4C4C4544-0043-4610-805A-C2C04F37354A
Comment 7 Dan Kenigsberg 2012-07-29 19:28:59 UTC 
I have a partial(!) suggested patch http://gerrit.ovirt.org/4881 which generates a random uuid upon bootstrap/installation. If we store this uuid in /etc/libvirt/libvirtd.conf, it would be used by libvirt for host identification.

Note that attaching <_rhevm-mac> to a non-unique uuid is broken, since macs change when nics fail or reconfigured.
Comment 8 Yaniv Kaul 2012-07-29 19:42:31 UTC 
(In reply to comment #7)
> I have a partial(!) suggested patch http://gerrit.ovirt.org/4881 which
> generates a random uuid upon bootstrap/installation. If we store this uuid
> in /etc/libvirt/libvirtd.conf, it would be used by libvirt for host
> identification.
> 
> Note that attaching <_rhevm-mac> to a non-unique uuid is broken, since macs
> change when nics fail or reconfigured.

it's not entirely broken - the fact we didn't store it (and use it) after creation is.
Comment 9 Itamar Heim 2012-07-29 20:10:33 UTC 
isn't changing the logic of uuid generation will cause rhev-h nodes to re-register themselves as new entities based on their now new uuid?
Comment 10 Jaroslav Henner 2012-07-29 20:22:11 UTC 
What if hypervisor generated UUID upon it's installation? Couldn't some RHN registration number be used as UUID? Or it's hash?
Comment 11 Dan Kenigsberg 2012-07-29 21:04:09 UTC 
(In reply to comment #9)
> isn't changing the logic of uuid generation will cause rhev-h nodes to
> re-register themselves as new entities based on their now new uuid?

it is. and it is the first "known issue" of http://gerrit.ovirt.org/4881 .

(In reply to comment #10)
> What if hypervisor generated UUID upon it's installation? Couldn't some RHN
> registration number be used as UUID? Or it's hash?

sorry, I did not get the question.
Comment 12 Jaroslav Henner 2012-07-30 07:38:16 UTC 
(In reply to comment #11)
> (In reply to comment #9)
> > isn't changing the logic of uuid generation will cause rhev-h nodes to
> > re-register themselves as new entities based on their now new uuid?
> 
> it is. and it is the first "known issue" of http://gerrit.ovirt.org/4881 .
> 
> (In reply to comment #10)
> > What if hypervisor generated UUID upon it's installation? Couldn't some RHN
> > registration number be used as UUID? Or it's hash?
> 
> sorry, I did not get the question.

I was just suggesting how the host identity could be generated. I have one more suggestion: hash of the ssh public key could be used as UUID.
Comment 14 Dan Kenigsberg 2012-08-05 10:31:45 UTC 
(In reply to comment #12)
> 
> I was just suggesting how the host identity could be generated. I have one
> more suggestion: hash of the ssh public key could be used as UUID.

Thanks, but I see no problem in using `uuidgen` or Python's uuid.uuid4(). There is no need for cryptographic safety here.
Comment 15 Sadique Puthen 2012-08-14 18:47:03 UTC 
*** Bug 760087 has been marked as a duplicate of this bug. ***
Comment 16 Yaniv Bronhaim 2012-08-22 06:32:16 UTC 
suggest patch: http://gerrit.ovirt.org/#/c/7332/
Comment 20 errata-xmlrpc 2012-12-04 19:03:10 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2012-1508.html
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