[CentOS] ntpd heavy CPU consumption

Thu Aug 29 22:17:47 UTC 2013
SilverTip257 <silvertip257 at gmail.com>

On Thu, Aug 29, 2013 at 5:32 PM, Steve Thompson <smt at vgersoft.com> wrote:

> CentOS 6.4, x86_64.
> ntpd on one of my systems has started consuming 66% of one core, although
> it appears to be functioning correctly otherwise. No pertinent logs. Of

Did you take a peek at the traffic going to this server?

Since you haven't specified, I figure this is just an ntp client and not an
ntp server.  Is that right?

Depending on your configuration (network ACLs, iptables on the host, and
ntpd.conf config on the host) maybe your server is being used in a denial
of service attack.

> course, nothing was changed :) I've seen this before many times, but
> usually the CPU consumption falls back to normal within a day or so, but
> this has been going on for several weeks now. Stopping and restarting ntpd
> makes no difference. Reinstalling ntpd makes no difference. The ntpd.conf
> file is the same as on 200+ other systems, all of which work normally.
> Anyone seen this before?

You might consider running strace on the ntp process when it decides to
ramp and consume CPU cycles.

> Steve
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//  SilverTip257  //