Check how the server is set, “RTC time” is your hardware clock…
root@ubuntu01:/# timedatectl Local time: Wed 2015-10-28 14:51:18 CET Universal time: Wed 2015-10-28 13:51:18 UTC RTC time: Wed 2015-10-28 13:52:41 Timezone: Europe/Stockholm (CET, +0100) NTP enabled: yes NTP synchronized: no RTC in local TZ: no DST active: no Last DST change: DST ended at Sun 2015-10-25 02:59:59 CEST Sun 2015-10-25 02:00:00 CET Next DST change: DST begins (the clock jumps one hour forward) at Sun 2016-03-27 01:59:59 CET Sun 2016-03-27 03:00:00 CEST
The ntp daemon ntpd calculates the drift of your system clock and continuously adjusts it, so there are no large corrections that could lead to inconsistent logs for instance.
install ntpd:
root@ubuntu01:/# sudo apt-get install ntp Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: libopts25 Suggested packages: ntp-doc The following NEW packages will be installed: libopts25 ntp 0 upgraded, 2 newly installed, 0 to remove and 95 not upgraded. Need to get 474 kB of archives. After this operation, 1,677 kB of additional disk space will be used. Do you want to continue? [Y/n] Y Get:1 http://se.archive.ubuntu.com/ubuntu/ trusty/main libopts25 amd64 1:5.18-2ubuntu2 [55.3 kB] Get:2 http://se.archive.ubuntu.com/ubuntu/ trusty-updates/main ntp amd64 1:4.2.6.p5+dfsg-3ubuntu2.14.04.5 [419 kB] Fetched 474 kB in 0s (831 kB/s) Selecting previously unselected package libopts25:amd64. (Reading database ... 58224 files and directories currently installed.) Preparing to unpack .../libopts25_1%3a5.18-2ubuntu2_amd64.deb ... Unpacking libopts25:amd64 (1:5.18-2ubuntu2) ... Selecting previously unselected package ntp. Preparing to unpack .../ntp_1%3a4.2.6.p5+dfsg-3ubuntu2.14.04.5_amd64.deb ... Unpacking ntp (1:4.2.6.p5+dfsg-3ubuntu2.14.04.5) ... Processing triggers for ureadahead (0.100.0-16) ... Processing triggers for man-db (2.6.7.1-1ubuntu1) ... Setting up libopts25:amd64 (1:5.18-2ubuntu2) ... Setting up ntp (1:4.2.6.p5+dfsg-3ubuntu2.14.04.5) ... * Starting NTP server ntpd [ OK ] Processing triggers for libc-bin (2.19-0ubuntu6.6) ... Processing triggers for ureadahead (0.100.0-16) ...
Configure ntp.conf with your pool, mine is the swedish pool found at
http://www.pool.ntp.org/zone/se
root@ubuntu01:/# vi /etc/ntp.conf
change these:
server 0.ubuntu.pool.ntp.org server 1.ubuntu.pool.ntp.org server 2.ubuntu.pool.ntp.org server 3.ubuntu.pool.ntp.org
to these:
server 0.se.pool.ntp.org server 1.se.pool.ntp.org server 2.se.pool.ntp.org server 3.se.pool.ntp.org
Checking that ntp is started at boot time
root@ubuntu01:/# sysv-rc-conf --list acpid apache2 0:off 1:off 2:on 3:on 4:on 5:on 6:off apparmor S:on apport atd console-setu cron dbus ddclient 1:off 2:on 3:on 4:on 5:on dns-clean 1:on 2:on 3:on 4:on 5:on friendly-rec grub-common 2:on 3:on 4:on 5:on halt 0:on iptables-per 0:off 1:off 2:on 3:on 4:on 5:on 6:off irqbalance killprocs 1:on kmod mysql networking ntp 1:off 2:on 3:on 4:on 5:on ondemand 2:on 3:on 4:on 5:on pppd-dns 1:on 2:on 3:on 4:on 5:on procps rc.local 2:on 3:on 4:on 5:on reboot 6:on resolvconf rsync 0:off 1:off 2:on 3:on 4:on 5:on 6:off rsyslog screen-clean 0:off 1:off 2:on 3:on 4:on 5:on 6:off sendsigs 0:on 6:on single 1:on ssh sudo udev umountfs 0:on 6:on umountroot 0:on 6:on unattended-u 0:off 6:off urandom 0:on 6:on S:on
looks okay, so lets reload the new config…
root@ubuntu01:/# service ntp reload
verify the daemon is running with the pstree -p command
root@ubuntu01:/# pstree -p
│
├─ntpd(1716)
├─rsyslogd(688)─┬─{rsyslogd}(689)
│ ├─{rsyslogd}(690)
│ └─{rsyslogd}(691)
├─sshd(939)─┬─sshd(1970)───sshd(1971)
│ └─sshd(32233)───sshd(32316)───bash(32317)───sudo(32449)───bash(32452)───pstree(1972)
├─systemd-logind(685)
├─systemd-udevd(289)
├─upstart-file-br(704)
├─upstart-socket-(707)
└─upstart-udev-br(284)
Sweet, now sync the system clock with the hwclock:
root@ubuntu01:/# hwclock --systohc
and verify:
root@ubuntu01:/# timedatectl Local time: Wed 2015-10-28 15:10:15 CET Universal time: Wed 2015-10-28 14:10:15 UTC RTC time: Wed 2015-10-28 14:10:15 Timezone: Europe/Stockholm (CET, +0100) NTP enabled: yes NTP synchronized: no RTC in local TZ: no DST active: no Last DST change: DST ended at Sun 2015-10-25 02:59:59 CEST Sun 2015-10-25 02:00:00 CET Next DST change: DST begins (the clock jumps one hour forward) at Sun 2016-03-27 01:59:59 CET Sun 2016-03-27 03:00:00 CEST
All done!