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Re: google compute engine health check or DoS?



Thanks for the log data. Can I suggest that you mention what happened on the gce-discussion list linked from the support page? The right people will probably follow up there. (I'm there too.)

It doesn't actually answer whether or not there was a DoS as the ultimate cause, only that your instance had suffered the kernel messages as the immediate cause of the outage. Certainly it provides less reason to think a DoS occurred.

In the meantime, try the kernel from wheezy-backports. It's known to perform much better (both in GCE and elsewhere), and also has some important bug fixes that are harder than the memory leak fix to integrate into wheezy's 3.2 kernel. These are all a big part of why we offer the backports image, though of course users who know Debian enough can add it in the regular image.

While the backports kernel doesn't get Debian security team support, the kernel team does maintain and periodically update the backport (admittedly not as fast as the security team patches).

If you want to switch to the backports kernel and receive updates to it in routine apt-get dist-upgrades, examine /etc/apt/*.d/*backports* on a backports image-based instance or look at https://github.com/google/build-debian-cloud/blob/master/tasks/gce/21-apt-backport-sources and https://github.com/google/build-debian-cloud/blob/master/tasks/gce/21-prefer-backports-kernel to see how we add it. (You can also grab the backports image tarball via gsutil from gs://debian_images if you prefer to examine it locally.)

Have a good weekend!

- Jimmy

Good morning, Jimmy-

Thanks for https://cloud.google.com/support/ reference. I see many
unanswered questions, though ;-)

On Fri, Mar 21, 2014 at 10:23 PM, Jimmy Kaplowitz <jkaplowitz@google.com> wrote:
> You too!
>
> By the way, if you want a broader range of people providing support
> (including external peers and GCE Googlers who may not be part of the Debian
> community), check out the self-service and community support options here,
> including a Google Group aka mailing list and a Stack overflow tag (paid
> support also available):
>
> https://cloud.google.com/support/
>
> Now that I've finished an unrelated email, actually going to sleep for real.
> :) /me waves good night! Feel free to say hello on IRC any time.
>
> - Jimmy

After changing DNS to CloudFlare's, I did not notice any
improvement(s). Thus at around 23:11pm I rebooted (with gcutil
resetinstance) and subsequently I was able to log in via gcutil
(indeed ssh functions, too).

Analyzing syslog it seems that the GCE instance began having issues at
around 18:54 pm beginning with the line:

Mar 21 18:54:34 my-gce-instance kernel: [3502320.420053] INFO: task
kswapd0:18 blocked for more than 120 seconds.
[...]

Accordingly, issue that began this thread appears to be kernel
related; I have sent you an edited version of syslog (leaving the
kernel related stuff intact) in case you want to analyze it.

uname -a

Linux my-gce-instance 3.2.0-4-amd64 #1 SMP Debian 3.2.54-2 x86_64 GNU/Linux

Although my GCE Console  graph shows sustained spikes, the range of
values seems normal; thus, it was not a DoS/DDoS after all.


Best Professional Regards.

$ cat /etc/os*

PRETTY_NAME="Debian GNU/Linux 7 (wheezy)"
NAME="Debian GNU/Linux"
VERSION_ID="7"
VERSION="7 (wheezy)"
ID=debian
ANSI_COLOR="1;31"
HOME_URL="http://www.debian.org/"
SUPPORT_URL="http://www.debian.org/support/"
BUG_REPORT_URL="http://bugs.debian.org/"

--
Jose R R
http://www.metztli-it.com
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