OK, I changed those lines in /etc/ntp.conf; let's see how that goes.

On Mon, Nov 21, 2016 at 7:19 AM, Todd Lipcon <[email protected]> wrote:
> On Sat, Nov 19, 2016 at 10:50 AM, Jim Apple <[email protected]> wrote:
>
>> Can you do so?
>>
>> This job used ntpwait before starting and has syslog sent to the
>> output; perhaps that will help debug:
>>
>> http://ec2-35-161-220-160.us-west-2.compute.amazonaws.com:80
>> 80/job/ubuntu-14.04-from-scratch/147/
>>
>>
> Yea, looks from the last ntptime output that it lost its NTP
> synchronization. Looking at the startup log it appears that it's just
> configured with the default Ubuntu NTP servers rather than using multiple
> hosts inside EC2. Is it possible for you to adjust your AMI or change the
> startup script to use the following lines in /etc/ntp.conf?
>
> server 0.amazon.pool.ntp.org
> server 1.amazon.pool.ntp.org
> server 2.amazon.pool.ntp.org
> server 3.amazon.pool.ntp.org
>
> We could add a flag to ignore NTP sync, but it looks like once NTP goes out
> of sync it's also reporting a maxerror of 16 seconds, which would also
> cause an issue.
>
> -Todd
>
>
>> In the meantime, it seems we could use a workaround in order to get
>> this working in ec2 more consistently.
>>
>> On Thu, Nov 17, 2016 at 12:21 PM, Todd Lipcon <[email protected]> wrote:
>> > Nothing else comes to mind. Let me know if you think the solution of
>> > allowing Kudu to ignore NTP status is preferable and I'll prioritize a
>> > patch to unblock you guys.
>> >
>> > -Todd
>> >
>> > On Thu, Nov 17, 2016 at 11:43 AM, Jim Apple <[email protected]>
>> wrote:
>> >
>> >> This is a normal functional test. The node is gone now, but I will add
>> >> "cat /var/log/syslog" to the logging. Anything else I should add?
>> >>
>> >> On Thu, Nov 17, 2016 at 10:55 AM, Todd Lipcon <[email protected]>
>> wrote:
>> >> > On Thu, Nov 17, 2016 at 10:52 AM, Jim Apple <[email protected]>
>> >> wrote:
>> >> >
>> >> >> The kudu master failure was at 16:36:28 UTC, but at 13:57:55 and
>> >> >> 15:58:41 we have ntptime printing "status 0x2001 (PLL,NANO),".
>> >> >>
>> >> >
>> >> > Do you see anything from ntp in /var/log/messages or syslog, etc?
>> Usually
>> >> > once NTP is synchronized it's fairly hard to knock it out of sync
>> unless
>> >> it
>> >> > loses internet access. Is this a stress test or normal functional
>> tests?
>> >> >
>> >> >
>> >> >>
>> >> >> On Thu, Nov 17, 2016 at 10:14 AM, Todd Lipcon <[email protected]>
>> >> wrote:
>> >> >> > On Thu, Nov 17, 2016 at 10:00 AM, Jim Apple <[email protected]>
>> >> >> wrote:
>> >> >> >
>> >> >> >> I now have a Kudu master failing with "F1117 16:36:26.940562
>> 113049
>> >> >> >> hybrid_clock.cc:227] Couldn't get the current time: Clock
>> >> >> >> unsynchronized. Status: Service unavailable: Error reading clock.
>> >> >> >> Clock considered unsynchronized"
>> >> >> >>
>> >> >> >> Todd, when you say "we need to wait for sync before running tests
>> or
>> >> >> >> allow an unsafe flag to disable the check," do you mean "we"
>> Impala,
>> >> >> >> "we" Kudu, or both? If Kudu or both, is there a Kudu bug I should
>> >> >> >> follow? I don't see a likely candidate at
>> >> >> >>
>> >> >> >> https://issues.apache.org/jira/browse/KUDU-1202?jql=
>> >> >> >> project%20%3D%20KUDU%20AND%20text%20~%20%22%5C%22Clock%
>> >> >> >> 20considered%20unsynchronized%5C%22%22
>> >> >> >
>> >> >> >
>> >> >> > Sorry, I was on my phone so wasn't as precise as I should have
>> been. I
>> >> >> > think that either:
>> >> >> >
>> >> >> > (a) Impala could add a script which runs prior to tests which waits
>> >> for
>> >> >> > synchronization. Apparently there is a builtin "ntp-wait" command
>> in
>> >> some
>> >> >> > distros. We use the following which also includes restarting NTP a
>> few
>> >> >> > times which seems to speed things up:
>> >> >> > https://gist.github.com/toddlipcon/97f7c8a4cf1d9c2551bd4289b
>> 97dfe48
>> >> >> >
>> >> >> > (b) Kudu could add a flag like --ignore_bad_ntp_sync_status which
>> you
>> >> >> could
>> >> >> > use in minicluster tests. In a minicluster where all the daemons
>> run
>> >> on
>> >> >> one
>> >> >> > node, it's sort of guaranteed that the clocks are in sync, so maybe
>> >> it's
>> >> >> > not too bad of an idea. The only risk I can see is that the clock
>> >> might
>> >> >> be
>> >> >> > adjusted backwards if NTP is not in sync status yet, and we may
>> have
>> >> some
>> >> >> > assertions which would be unhappy if that happened. We could give
>> it a
>> >> >> try,
>> >> >> > though, if the "wait-for-ntp" approach doesn't help.
>> >> >> >
>> >> >> > -Todd
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> >>
>> >> >> >>
>> >> >> >> On Wed, Nov 16, 2016 at 2:19 PM, Todd Lipcon <[email protected]>
>> >> wrote:
>> >> >> >> > This particular error message isn't related to the clock error
>> >> itself.
>> >> >> >> It's
>> >> >> >> > the sync status flag which indicates whether NTP thinks its
>> phase
>> >> lock
>> >> >> >> loop
>> >> >> >> > is in sync or not. So, changing the allowed error shouldn't have
>> >> any
>> >> >> >> > effect. Instead we need to wait for sync before running tests or
>> >> >> allow an
>> >> >> >> > unsafe flag to disable the check.
>> >> >> >> >
>> >> >> >> > On Nov 16, 2016 1:55 PM, "Matthew Jacobs" <[email protected]>
>> wrote:
>> >> >> >> >
>> >> >> >> >> Yeah, I don't doubt that the ntp output when you checked it was
>> >> >> wrong,
>> >> >> >> >> but it may be different from the time when Kudu failed to
>> start,
>> >> >> since
>> >> >> >> >> that was probably at least several minutes later (assuming you
>> >> had to
>> >> >> >> >> find out about the failed job, ssh into the machine, discover
>> the
>> >> ntp
>> >> >> >> >> warning and then check it at that time).
>> >> >> >> >>
>> >> >> >> >> I agree adding some logging at the beginning of jobs is the
>> best
>> >> >> thing
>> >> >> >> >> to do now.
>> >> >> >> >>
>> >> >> >> >> Thanks!
>> >> >> >> >>
>> >> >> >> >> On Wed, Nov 16, 2016 at 11:38 AM, Jim Apple <
>> [email protected]
>> >> >
>> >> >> >> wrote:
>> >> >> >> >> > I found a place where I suppose that could go
>> >> >> >> >> > (testdata/cluster/node_templates/cdh5/etc/kudu/), but I'm
>> not
>> >> sure
>> >> >> >> >> > what I want to set it at. If "maximum error 197431 us" is to
>> be
>> >> >> >> >> > believed, it needs to be at least 0.2 seconds, and if
>> >> >> >> >> > https://kudu.apache.org/docs/troubleshooting.html is to be
>> >> >> believed,
>> >> >> >> >> > it is already 10 seconds.
>> >> >> >> >> >
>> >> >> >> >> > I added some more logging to try and see what is going on,
>> and
>> >> if I
>> >> >> >> >> > hit this again I'll re-open the thread. For now, I am not
>> >> planning
>> >> >> to
>> >> >> >> >> > submit a patch to "fix" it because I'm not sure increasing
>> the
>> >> >> number
>> >> >> >> >> > is the real solution.
>> >> >> >> >> >
>> >> >> >> >> > On Wed, Nov 16, 2016 at 11:00 AM, Matthew Jacobs <
>> >> [email protected]>
>> >> >> >> >> wrote:
>> >> >> >> >> >> According to the error message, it looks like we can specify
>> >> the
>> >> >> >> >> >> '--max_clock_sync_error_usec' flag when starting the Kudu
>> >> >> processes.
>> >> >> >> >> >> We may want to start by printing ntptime output at the
>> >> beginning
>> >> >> of
>> >> >> >> >> >> jobs so we can see how far off it is. If it's off by days
>> then
>> >> >> maybe
>> >> >> >> >> >> changing the error isn't a good idea, and we'll need to
>> figure
>> >> out
>> >> >> >> >> >> something else.
>> >> >> >> >> >>
>> >> >> >> >> >> On Wed, Nov 16, 2016 at 10:55 AM, Jim Apple <
>> >> [email protected]
>> >> >> >
>> >> >> >> >> wrote:
>> >> >> >> >> >>> How do we bump up the allowable error?
>> >> >> >> >> >>>
>> >> >> >> >> >>> On Wed, Nov 16, 2016 at 10:20 AM, Matthew Jacobs <
>> >> >> [email protected]>
>> >> >> >> >> wrote:
>> >> >> >> >> >>>> I asked on the Kudu slack channel, they have seen issues
>> >> where
>> >> >> >> freshly
>> >> >> >> >> >>>> provisioned ec2 nodes take some time for ntp to quiesce,
>> but
>> >> >> they
>> >> >> >> >> >>>> didn't have a sense of how long that might take. If you
>> >> checked
>> >> >> >> >> >>>> ntptime after the job failed, it may be that ntp had
>> enough
>> >> >> time.
>> >> >> >> We
>> >> >> >> >> >>>> can probably consider bumping up the allowable error.
>> >> >> >> >> >>>>
>> >> >> >> >> >>>> On Wed, Nov 16, 2016 at 9:24 AM, Jim Apple <
>> >> >> [email protected]>
>> >> >> >> >> wrote:
>> >> >> >> >> >>>>> This is the second time I have seen it, but it doesn't
>> >> happen
>> >> >> >> every
>> >> >> >> >> >>>>> time. It could very well be a difference on ec2; already
>> >> I've
>> >> >> seen
>> >> >> >> >> >>>>> some bugs due to my ec2 instances being Etc/UTC timezone
>> >> while
>> >> >> >> most
>> >> >> >> >> >>>>> Impala developers work in America/Los_Angeles.
>> >> >> >> >> >>>>>
>> >> >> >> >> >>>>> On Wed, Nov 16, 2016 at 9:10 AM, Matthew Jacobs <
>> >> >> [email protected]>
>> >> >> >> >> wrote:
>> >> >> >> >> >>>>>> No problem. If this happens again we should ask the Kudu
>> >> >> >> >> developers. I
>> >> >> >> >> >>>>>> haven't seen this before - I wonder if it could be some
>> >> >> >> weirdness on
>> >> >> >> >> >>>>>> ec2...
>> >> >> >> >> >>>>>>
>> >> >> >> >> >>>>>> Thanks
>> >> >> >> >> >>>>>>
>> >> >> >> >> >>>>>> On Wed, Nov 16, 2016 at 9:01 AM, Jim Apple <
>> >> >> [email protected]
>> >> >> >> >
>> >> >> >> >> wrote:
>> >> >> >> >> >>>>>>> Thank you for your help!
>> >> >> >> >> >>>>>>>
>> >> >> >> >> >>>>>>> This was on an AWS machine that has expired, but I can
>> see
>> >> >> from
>> >> >> >> the
>> >> >> >> >> >>>>>>> logs that "IMPALA_KUDU_VERSION=88b023" and
>> >> >> >> >> >>>>>>> "KUDU_JAVA_VERSION=1.0.0-SNAPSHOT" and "Downloading
>> >> >> >> >> >>>>>>> kudu-python-0.3.0.tar.gz" and "URL
>> >> >> >> >> >>>>>>> https://native-toolchain.s3.amazonaws.com/build/264-
>> >> >> >> >> e9d44349ba/kudu/88b023-gcc-4.9.2/kudu-88b023-gcc-4.9.2-ec2-
>> >> >> >> >> package-ubuntu-14-04.tar.gz".
>> >> >> >> >> >>>>>>> I'll add "ps aux | grep kudu" to the logging this
>> machine
>> >> >> does
>> >> >> >> on
>> >> >> >> >> >>>>>>> error, so we'll have it next time, but I did "ps
>> -Afly" on
>> >> >> exit
>> >> >> >> and
>> >> >> >> >> >>>>>>> there were no kudu processes running, it looks like.
>> >> >> >> >> >>>>>>>
>> >> >> >> >> >>>>>>> On Wed, Nov 16, 2016 at 8:52 AM, Matthew Jacobs <
>> >> >> >> [email protected]>
>> >> >> >> >> wrote:
>> >> >> >> >> >>>>>>>> Can you check which version of the client you're
>> building
>> >> >> >> against
>> >> >> >> >> >>>>>>>> (KUDU_VERSION env var) vs what Kudu version is running
>> >> (ps
>> >> >> aux
>> >> >> >> |
>> >> >> >> >> grep
>> >> >> >> >> >>>>>>>> kudu
>> >> >> >> >> >>>>>>>>
>> >> >> >> >> >>>>>>>> On Wed, Nov 16, 2016 at 8:48 AM, Jim Apple <
>> >> >> >> [email protected]>
>> >> >> >> >> wrote:
>> >> >> >> >> >>>>>>>>> Yes.
>> >> >> >> >> >>>>>>>>>
>> >> >> >> >> >>>>>>>>> On Wed, Nov 16, 2016 at 7:45 AM, Matthew Jacobs <
>> >> >> >> [email protected]>
>> >> >> >> >> wrote:
>> >> >> >> >> >>>>>>>>>> Do you have NTP installed?
>> >> >> >> >> >>>>>>>>>>
>> >> >> >> >> >>>>>>>>>> On Tue, Nov 15, 2016 at 9:22 PM, Jim Apple <
>> >> >> >> >> [email protected]> wrote:
>> >> >> >> >> >>>>>>>>>>> I have a machine where Kudu failed to start:
>> >> >> >> >> >>>>>>>>>>>
>> >> >> >> >> >>>>>>>>>>> F1116 05:02:00.173629 71098
>> tablet_server_main.cc:64]
>> >> >> Check
>> >> >> >> >> failed:
>> >> >> >> >> >>>>>>>>>>> _s.ok() Bad status: Service unavailable: Cannot
>> >> >> initialize
>> >> >> >> >> clock:
>> >> >> >> >> >>>>>>>>>>> Error reading clock. Clock considered
>> unsynchronized
>> >> >> >> >> >>>>>>>>>>>
>> >> >> >> >> >>>>>>>>>>> https://kudu.apache.org/docs/troubleshooting.html
>> >> says:
>> >> >> >> >> >>>>>>>>>>>
>> >> >> >> >> >>>>>>>>>>> "For the master and tablet server daemons, the
>> >> server’s
>> >> >> >> clock
>> >> >> >> >> must be
>> >> >> >> >> >>>>>>>>>>> synchronized using NTP. In addition, the maximum
>> clock
>> >> >> error
>> >> >> >> >> (not to
>> >> >> >> >> >>>>>>>>>>> be mistaken with the estimated error) be below a
>> >> >> >> configurable
>> >> >> >> >> >>>>>>>>>>> threshold. The default value is 10 seconds, but it
>> >> can be
>> >> >> >> set
>> >> >> >> >> with the
>> >> >> >> >> >>>>>>>>>>> flag --max_clock_sync_error_usec."
>> >> >> >> >> >>>>>>>>>>>
>> >> >> >> >> >>>>>>>>>>> and
>> >> >> >> >> >>>>>>>>>>>
>> >> >> >> >> >>>>>>>>>>> "If NTP is installed the user can monitor the
>> >> >> >> synchronization
>> >> >> >> >> status
>> >> >> >> >> >>>>>>>>>>> by running ntptime. The relevant value is what is
>> >> >> reported
>> >> >> >> for
>> >> >> >> >> maximum
>> >> >> >> >> >>>>>>>>>>> error."
>> >> >> >> >> >>>>>>>>>>>
>> >> >> >> >> >>>>>>>>>>> ntptime reports:
>> >> >> >> >> >>>>>>>>>>>
>> >> >> >> >> >>>>>>>>>>> ntp_gettime() returns code 0 (OK)
>> >> >> >> >> >>>>>>>>>>>   time dbd66a6a.59bca948  Wed, Nov 16 2016
>> >> 5:17:30.350,
>> >> >> >> >> (.350535824),
>> >> >> >> >> >>>>>>>>>>>   maximum error 197431 us, estimated error 71015
>> us,
>> >> TAI
>> >> >> >> >> offset 0
>> >> >> >> >> >>>>>>>>>>> ntp_adjtime() returns code 0 (OK)
>> >> >> >> >> >>>>>>>>>>>   modes 0x0 (),
>> >> >> >> >> >>>>>>>>>>>   offset 74989.459 us, frequency 19.950 ppm,
>> interval
>> >> 1
>> >> >> s,
>> >> >> >> >> >>>>>>>>>>>   maximum error 197431 us, estimated error 71015
>> us,
>> >> >> >> >> >>>>>>>>>>>   status 0x2001 (PLL,NANO),
>> >> >> >> >> >>>>>>>>>>>   time constant 6, precision 0.001 us, tolerance
>> 500
>> >> ppm,
>> >> >> >> >> >>>>>>>>>>>
>> >> >> >> >> >>>>>>>>>>> So it looks like this error is anticipated, but the
>> >> >> expected
>> >> >> >> >> >>>>>>>>>>> conditions for it to occur are absent. Any ideas
>> what
>> >> >> could
>> >> >> >> be
>> >> >> >> >> going
>> >> >> >> >> >>>>>>>>>>> on here? This is with a recent checkout of Impala
>> >> master.
>> >> >> >> >>
>> >> >> >>
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > --
>> >> >> > Todd Lipcon
>> >> >> > Software Engineer, Cloudera
>> >> >>
>> >> >
>> >> >
>> >> >
>> >> > --
>> >> > Todd Lipcon
>> >> > Software Engineer, Cloudera
>> >>
>> >
>> >
>> >
>> > --
>> > Todd Lipcon
>> > Software Engineer, Cloudera
>>
>
>
>
> --
> Todd Lipcon
> Software Engineer, Cloudera

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