On 11/06/2015 11:06 AM, Nathan Cutler wrote: > Hi Ceph: > > Recently I encountered some a "clock skew" issue with 0.94.3. I have > some small demo clusters in AWS. When I boot them up, in most cases the > cluster will start in HEALTH_WARN due to clock skew on some of the MONs. > > I surmise that this is due to a race condition between the ceph-mon and > ntpd systemd services. Sometimes ntpd.service starts *after* ceph-mon - > in this case the MON sees a wrong/unsynchronized time value. > > Now, even though ntpd.service starts (and fixes the time value) very > soon afterwards, the cluster remains in clock skew for a long time - but > that is a separate issue. What I would like to ask is this: > > Is there any reasonable Ceph cluster node configuration that does not > include running the NTP daemon? > Well, the MONs are very, very time sensitive. OSDs somewhat less, but if they drift too far they run into trouble authenticating. > If the answer is "no", would it make sense to make NTP a runtime > dependency and tell the ceph-mon systemd service to wait for > ntpd.service before it starts? > I think it makes sense, correct time is essential imho. > Thanks and regards > -- Wido den Hollander 42on B.V. Ceph trainer and consultant Phone: +31 (0)20 700 9902 Skype: contact42on -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
