The command 'service ntpd stop' could be triggered around 14:00. Because the crontab was set as follows: 0 * * * * sh sync.sh The script contains the following command: #!/bin/bash service ntpd stop ntpdate 192.168.0.1 #it's a valid ntpd server in LAN service ntpd start chkconfig ntpd on
Found the following fragment in /var/log/message: Jan 7 14:00:01 host1 ntpd[32101]: ntpd exiting on signal 15 Jan 7 13:59:59 host1 ntpd[44764]: ntpd [email protected] Fri Feb 22 11:23:27 UTC 2013 (1) Jan 7 13:59:59 host1 ntpd[44765]: precision = 0.143 usec Jan 7 13:59:59 host1 ntpd[44765]: Listening on interface #0 wildcard, 0.0.0.0#123 Disabled Jan 7 13:59:59 host1 ntpd[44765]: Listening on interface #1 wildcard, ::#123 Disabled Jan 7 13:59:59 host1 ntpd[44765]: Listening on interface #2 lo, ::1#123 Enabled Jan 7 13:59:59 host1 ntpd[44765]: Listening on interface #3 em2, fe80::ca1f:66ff:fee1:eed#123 Enabled Jan 7 13:59:59 host1 ntpd[44765]: Listening on interface #4 lo, 127.0.0.1#123 Enabled Jan 7 13:59:59 host1 ntpd[44765]: Listening on interface #5 em2, 192.168.1.151#123 Enabled Jan 7 13:59:59 host1 ntpd[44765]: Listening on routing socket on fd #22 for interface updates Jan 7 13:59:59 host1 ntpd[44765]: kernel time sync status 2040 Jan 7 13:59:59 host1 ntpd[44765]: frequency initialized 499.399 PPM from /var/lib/ntp/drift Jan 7 14:00:01 host1 ntpd_initres[32103]: parent died before we finished, exiting Jan 7 14:04:17 host1 ntpd[44765]: synchronized to 192.168.0.191, stratum 2 Jan 7 14:04:17 host1 ntpd[44765]: kernel time sync status change 2001 Jan 7 14:26:02 host1 snmpd[4842]: Received TERM or STOP signal... shutting down... Jan 7 14:26:02 host1 kernel: netlink: 12 bytes leftover after parsing attributes. Jan 7 14:26:02 host1 snmpd[45667]: NET-SNMP version 5.5 Jan 7 14:52:48 host1 ntpd[44765]: no servers reachable It looks likely the command 'service ntpd stop' send the SIGTERM signal. The above clue 'ntpd[32101]' indicates that the ntpd process PID is 32101, inspect NameNode log, i found that the NameNode process PID was not identical with ntpd. So i wonder why Namenode process can received the signal?
