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Leap second causing Linux server crashes?

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Re: Leap second causing Linux server crashes?

#101

Post by enneff »

ralph wrote: post #98
jbeda wrote: post #34

Earlier quoted context omitted.

As part of Google Compute Engine we provide an NTP server to the guest which is based on Google Production time. As such our VMs get to take advantage of this leap second smearing implementation. I was going to mention this at my talk at IO but forgot.

So a VM on G's Compute Engine could in turn run an NTP server that exported G's Production Time? Do I also see GPT on App Engine? Any chance Google could just make a GPT NTP server available as a public service anyway, just as 8.8.8.8 is their public ping responder. ;-)

8.8.8.8 and 8.8.4.4 are Google Public DNS, not a "ping responder." https://developers.google.com/speed/public-dns/

Google does provide time servers, although I'm not sure whether they are officially supported. The addresses are:

    time1.google.com
    time2.google.com
    time3.google.com
    time4.google.com

Re: Leap second causing Linux server crashes?

#102

Post by andreasvc »

chimeracoder wrote: post #63
Aqwis wrote: post #56

Earlier quoted context omitted.

Physics perfectly well knows what time is. This is an issue with keeping track of time in terms of seconds, minutes, hours and days, and has nothing to do with not knowing what time is.

What is time, other than a state in which net entropy within a closed system increases (which is already a definition abstract enough that it almost misses the point)?

That's not really a definition of time, just a way to postulate its direction. Time as a physical unit has been decreed to be the rate of decay of a certain Cesium atom; i.e., a fixed regular interval, whereas the increase of entropy varies from moment to moment. E.g. right now I'm typing and before I wasn't, that doesn't mean time is going ever so slightly faster because of that ...

Re: Leap second causing Linux server crashes?

#103

Post by andreasvc »

duiker101 wrote: post #8

2012. and we still have problems keeping track of time. This is both fascinating and scary. P.S. for people wanting to know more this video is simple to understand but really amazing http://www.youtube.com/watch?v=xX96xng7sAE

Nice video but what if we used Sidereal time? (i.e., star time, which ignores the earth's rotation around its axis).

Re: Leap second causing Linux server crashes?

#104

Post by jbeda »

ralph wrote: post #98
jbeda wrote: post #34

Earlier quoted context omitted.

As part of Google Compute Engine we provide an NTP server to the guest which is based on Google Production time. As such our VMs get to take advantage of this leap second smearing implementation. I was going to mention this at my talk at IO but forgot.

So a VM on G's Compute Engine could in turn run an NTP server that exported G's Production Time? Do I also see GPT on App Engine? Any chance Google could just make a GPT NTP server available as a public service anyway, just as 8.8.8.8 is their public ping responder. ;-)

I don't know about GAE specifically but I'd be very surprised if it didn't see the same time as the rest of Google. They would have had to do work to make that happen.

Re: Leap second causing Linux server crashes?

#105

Post by ralph »

enneff wrote: post #101
ralph wrote: post #98

Earlier quoted context omitted.

So a VM on G's Compute Engine could in turn run an NTP server that exported G's Production Time? Do I also see GPT on App Engine? Any chance Google could just make a GPT NTP server available as a public service anyway, just as 8.8.8.8 is their public ping responder. ;-)

8.8.8.8 and 8.8.4.4 are Google Public DNS, not a "ping responder." https://developers.google.com/speed/public-dns/ Google does provide time servers, although I'm not sure whether they are officially supported. The addresses are: time1.google.com time2.google.com time3.google.com time4.google.com

Yeah, sorry, I know they're the public DNS, but they're also jolly handy as unforgettable IP addresses you expect to be able to ping, hence the smiley.

Good news about the time{1..4} NTP servers, I'll give them a try, thanks.

Re: Leap second causing Linux server crashes?

#107

Post by wiredfool »

kristopher wrote: post #96

FYI: Our Debian servers did not kernel panic but system CPU load went through the roof; A quick restart brought levels back to normal.

My Ubuntu 10.04 desktop went to 100% proc and load avg of 20, none of my 10.04 servers or Debian stable servers were affected.

This fixed it:

  date; sudo date `date +"%m%d%H%M%C%y.%S"`; date;

Re: Leap second causing Linux server crashes?

#108

Post by brongondwana »

rplnt wrote: post #91
moe wrote: post #61

Earlier quoted context omitted.

Which, in summary, is pretty much every production kernel out there. Spent the last two hours recovering servers, tomorrow will be another interesting day. Whoever figured it'd be a good idea to INSERT[1] the leap-second instead of just slowing/accelerating time... [1] Clock: inserting leap second 23:59:60 UTC

Well, it was a known bug and you had six months to prepare (i.e. update your kernel).

Pity there was a missing bnx2 firmware issue in all the stables kernels since then, which makes most of the boxes I'm unfortunate enough to run even less useful.

Re: Leap second causing Linux server crashes?

#109

Post by rplnt »

moe wrote: post #97
rplnt wrote: post #91

Earlier quoted context omitted.

Well, it was a known bug and you had six months to prepare (i.e. update your kernel).

Where was it published? Almost all of my machines run the Debian stable kernel and were still affected.

The leap second was scheduled in January. That event is so unusual you might get worried. So you do a simple google search and find out that there was a critical bug[1] in Linux kernel last time leap second was inserted. People got worried rightfully[2][3]. I don't know about debian, if it was known prior, if it is the same bug as before, ... But I don't run Debian, you do.

1. https://bugzilla.redhat.com/show_bug.cgi?id=479765

2. http://it.slashdot.org/story/12/06/30/2123248/the-leap-secon...

3. http://serverfault.com/questions/402087/does-centos-5-4-prop...

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