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  1. Odd uuid-ossp behavior on smew and shearwater

    Tom Lane <tgl@sss.pgh.pa.us> — 2014-05-29T03:23:45Z

    Buildfarm critters smew and shearwater are reporting regression test
failures that suggest that the UUID library can't get a system MAC
address:
http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=smew&dt=2014-05-28%2023%3A38%3A28
http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=shearwater&dt=2014-05-29%2000%3A24%3A32

I've just committed regression test adjustments to prevent that from
being a failure case, but I am confused about why it's happening.
I wouldn't be surprised at not getting a MAC address on a machine that
lacks any internet connection, but that surely can't describe the
buildfarm environment.  Are you curious enough to poke into it and
see what's going on?  It might be useful to strace a backend that's
trying to execute uuid_generate_v1() and see what the kernel interaction
looks like exactly.

			regards, tom lane

  2. Re: Odd uuid-ossp behavior on smew and shearwater

    Josh Kupershmidt <schmiddy@gmail.com> — 2014-05-29T17:20:04Z

    On Wed, May 28, 2014 at 11:23 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Buildfarm critters smew and shearwater are reporting regression test
> failures that suggest that the UUID library can't get a system MAC
> address:
> http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=smew&dt=2014-05-28%2023%3A38%3A28
> http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=shearwater&dt=2014-05-29%2000%3A24%3A32
>
> I've just committed regression test adjustments to prevent that from
> being a failure case, but I am confused about why it's happening.
> I wouldn't be surprised at not getting a MAC address on a machine that
> lacks any internet connection, but that surely can't describe the
> buildfarm environment.  Are you curious enough to poke into it and
> see what's going on?  It might be useful to strace a backend that's
> trying to execute uuid_generate_v1() and see what the kernel interaction
> looks like exactly.

Here's the result of attaching strace to an idle backend, then running
SELECT uuid_generate_v1(). AFAIR shearwater is a cheaply-hosted OpenVZ
VPS under the hood.

Josh

  3. Re: Odd uuid-ossp behavior on smew and shearwater

    Tom Lane <tgl@sss.pgh.pa.us> — 2014-05-29T18:38:36Z

    Josh Kupershmidt <schmiddy@gmail.com> writes:
> On Wed, May 28, 2014 at 11:23 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I've just committed regression test adjustments to prevent that from
>> being a failure case, but I am confused about why it's happening.
>> I wouldn't be surprised at not getting a MAC address on a machine that
>> lacks any internet connection, but that surely can't describe the
>> buildfarm environment.  Are you curious enough to poke into it and
>> see what's going on?  It might be useful to strace a backend that's
>> trying to execute uuid_generate_v1() and see what the kernel interaction
>> looks like exactly.

> Here's the result of attaching strace to an idle backend, then running
> SELECT uuid_generate_v1(). AFAIR shearwater is a cheaply-hosted OpenVZ
> VPS under the hood.

Interesting.  Looks like you have access only to virtual network
interfaces, and they report all-zero MAC addresses, which the UUID library
is smart enough to ignore.  If smew is also in a virtual environment
then that's probably the explanation.  (There are some other buildfarm
critters that are reporting MAC addresses with the local-admin bit set,
which I suspect also means they've got virtual network interfaces, but
with a different treatment of the what-to-report problem.)

			regards, tom lane

  4. Re: Odd uuid-ossp behavior on smew and shearwater

    Andrew Dunstan <andrew@dunslane.net> — 2014-05-29T20:06:29Z

    On 05/29/2014 02:38 PM, Tom Lane wrote:
> Josh Kupershmidt <schmiddy@gmail.com> writes:
>> On Wed, May 28, 2014 at 11:23 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> I've just committed regression test adjustments to prevent that from
>>> being a failure case, but I am confused about why it's happening.
>>> I wouldn't be surprised at not getting a MAC address on a machine that
>>> lacks any internet connection, but that surely can't describe the
>>> buildfarm environment.  Are you curious enough to poke into it and
>>> see what's going on?  It might be useful to strace a backend that's
>>> trying to execute uuid_generate_v1() and see what the kernel interaction
>>> looks like exactly.
>> Here's the result of attaching strace to an idle backend, then running
>> SELECT uuid_generate_v1(). AFAIR shearwater is a cheaply-hosted OpenVZ
>> VPS under the hood.
> Interesting.  Looks like you have access only to virtual network
> interfaces, and they report all-zero MAC addresses, which the UUID library
> is smart enough to ignore.  If smew is also in a virtual environment
> then that's probably the explanation.  (There are some other buildfarm
> critters that are reporting MAC addresses with the local-admin bit set,
> which I suspect also means they've got virtual network interfaces, but
> with a different treatment of the what-to-report problem.)
>
> 			



Almost all my critters run in VMs (all but jacana and bowerbird).

cheers

andrew

  5. Re: Odd uuid-ossp behavior on smew and shearwater

    Josh Kupershmidt <schmiddy@gmail.com> — 2014-05-29T21:41:21Z

    On Thu, May 29, 2014 at 4:06 PM, Andrew Dunstan <andrew@dunslane.net> wrote:
> On 05/29/2014 02:38 PM, Tom Lane wrote:
>> Josh Kupershmidt <schmiddy@gmail.com> writes:
>> Interesting.  Looks like you have access only to virtual network
>> interfaces, and they report all-zero MAC addresses, which the UUID library
>> is smart enough to ignore.  If smew is also in a virtual environment
>> then that's probably the explanation.  (There are some other buildfarm
>> critters that are reporting MAC addresses with the local-admin bit set,
>> which I suspect also means they've got virtual network interfaces, but
>> with a different treatment of the what-to-report problem.)

> Almost all my critters run in VMs (all but jacana and bowerbird).

They're not running on OpenVZ, are they? `ifconfig` on shearwater says:

venet0    Link encap:UNSPEC  HWaddr
00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          inet addr:127.0.0.2  P-t-P:127.0.0.2  Bcast:0.0.0.0
Mask:255.255.255.255
          UP BROADCAST POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1
          RX packets:1409294 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1488401 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:751149524 (716.3 MiB)  TX bytes:740573200 (706.2 MiB)

venet0:0  Link encap:UNSPEC  HWaddr
00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          inet addr:198.204.250.34  P-t-P:198.204.250.34
Bcast:0.0.0.0  Mask:255.255.255.255
          UP BROADCAST POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1

and it seems this all-zeros MAC address is a common
(mis-?)configuration on OpenVZ:

https://github.com/robertdavidgraham/masscan/issues/43
http://stackoverflow.com/questions/5838225/how-do-i-get-a-default-gridgain-node-in-openvz-discover-other-nodes-on-the-same
http://forum.openvz.org/index.php?t=msg&goto=8117

  6. Re: Odd uuid-ossp behavior on smew and shearwater

    Andrew Dunstan <andrew@dunslane.net> — 2014-05-29T22:45:37Z

    On 05/29/2014 05:41 PM, Josh Kupershmidt wrote:
> On Thu, May 29, 2014 at 4:06 PM, Andrew Dunstan <andrew@dunslane.net> wrote:
>> Almost all my critters run in VMs (all but jacana and bowerbird).
> They're not running on OpenVZ, are they? `ifconfig` on shearwater says:
>
[...]
> and it seems this all-zeros MAC address is a common
> (mis-?)configuration on OpenVZ:
>
> https://github.com/robertdavidgraham/masscan/issues/43
> http://stackoverflow.com/questions/5838225/how-do-i-get-a-default-gridgain-node-in-openvz-discover-other-nodes-on-the-same
> http://forum.openvz.org/index.php?t=msg&goto=8117
>



Yeah, that's a bit ugly. Mine are on qemu, one (sitella) is on Xen.

cheers

andrew

  7. Re: Odd uuid-ossp behavior on smew and shearwater

    Magnus Hagander <magnus@hagander.net> — 2014-05-30T11:23:09Z

    On Fri, May 30, 2014 at 12:45 AM, Andrew Dunstan <andrew@dunslane.net>
wrote:

>
> On 05/29/2014 05:41 PM, Josh Kupershmidt wrote:
>
>> On Thu, May 29, 2014 at 4:06 PM, Andrew Dunstan <andrew@dunslane.net>
>> wrote:
>>
>>> Almost all my critters run in VMs (all but jacana and bowerbird).
>>>
>> They're not running on OpenVZ, are they? `ifconfig` on shearwater says:
>>
>>  [...]
>
>  and it seems this all-zeros MAC address is a common
>> (mis-?)configuration on OpenVZ:
>>
>> https://github.com/robertdavidgraham/masscan/issues/43
>> http://stackoverflow.com/questions/5838225/how-do-i-
>> get-a-default-gridgain-node-in-openvz-discover-other-nodes-on-the-same
>> http://forum.openvz.org/index.php?t=msg&goto=8117
>>
>>
>
>
> Yeah, that's a bit ugly. Mine are on qemu, one (sitella) is on Xen.
>

That's likely the difference between real virtualization and
containerization. It'd be interesting to see how it behaves on FreeBSD
jails or LXC-containers.

-- 
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/