UNIX for Beginners Questions & Answers

wget https://download.tuxfamily.org/chrony/chrony-3.5.tar.gz
tar xvzf chrony-3.5.tar.gztar xvzf chrony-3.5.tar.gz
cat INSTALL
./configure --disable-readline other-options
make all
vi /etc/chrony.conf
ps aux | grep chron* | grep -v grep

root     28922  0.0  0.0  97024  2620 ?        S    23:29   0:00 /usr/local/sbin/chronyd

cd /var/log
grep chrony *log

syslog:Sep 25 23:29:44 www chronyd[28922]: chronyd version 3.5 starting (+CMDMON +NTP +REFCLOCK +RTC -PRIVDROP -SCFILTER -SIGND +ASYNCDNS -SECHASH +IPV6 -DEBUG)
syslog:Sep 25 23:29:44 www chronyd[28922]: Initial frequency 16.866 ppm
syslog:Sep 25 23:29:49 www chronyd[28922]: Selected source 104.168.88.15

cat /etc/chrony.conf
pool pool.ntp.org iburst
makestep 1.0 3
rtcsync
port 0

apt install chrony
ps aux | grep chron | grep -v grep
_chrony  19064  0.0  0.1 108304  3092 ?        S    04:55   0:00 /usr/sbin/chronyd

cat /etc/chrony/chrony.conf

root@localhost:/etc/chrony# cat chrony.conf
# Welcome to the chrony configuration file. See chrony.conf(5) for more
# information about usuable directives.

# This will use (up to):
# - 4 sources from ntp.ubuntu.com which some are ipv6 enabled
# - 2 sources from 2.ubuntu.pool.ntp.org which is ipv6 enabled as well
# - 1 source from [01].ubuntu.pool.ntp.org each (ipv4 only atm)
# This means by default, up to 6 dual-stack and up to 2 additional IPv4-only
# sources will be used.
# At the same time it retains some protection against one of the entries being
# down (compare to just using one of the lines). See (LP: #1754358) for the
# discussion.
#
# About using servers from the NTP Pool Project in general see (LP: #104525).
# Approved by Ubuntu Technical Board on 2011-02-08.
# See http://www.pool.ntp.org/join.html for more information.
pool ntp.ubuntu.com        iburst maxsources 4
pool 0.ubuntu.pool.ntp.org iburst maxsources 1
pool 1.ubuntu.pool.ntp.org iburst maxsources 1
pool 2.ubuntu.pool.ntp.org iburst maxsources 2

# This directive specify the location of the file containing ID/key pairs for
# NTP authentication.
keyfile /etc/chrony/chrony.keys

# This directive specify the file into which chronyd will store the rate
# information.
driftfile /var/lib/chrony/chrony.drift

# Uncomment the following line to turn logging on.
#log tracking measurements statistics

# Log files location.
logdir /var/log/chrony

# Stop bad estimates upsetting machine clock.
maxupdateskew 100.0

# This directive enables kernel synchronisation (every 11 minutes) of the
# real-time clock. Note that it can't be used along with the 'rtcfile' directive.
rtcsync

# Step the system clock instead of slewing it if the adjustment is larger than
# one second, but only in the first three clock updates.
makestep 1 3

#If you don't need to serve time to NTP clients or peers, you can add port 0 to the chrony.conf file 
# to completely disable the NTP server functionality and prevent NTP requests from reaching chronyd
port 0

cd /var/log
grep chrony *log

auth.log:Sep 26 04:55:13 localhost groupadd[18713]: group added to /etc/group: name=_chrony, GID=115
auth.log:Sep 26 04:55:13 localhost groupadd[18713]: group added to /etc/gshadow: name=_chrony
auth.log:Sep 26 04:55:13 localhost groupadd[18713]: new group: name=_chrony, GID=115
auth.log:Sep 26 04:55:13 localhost useradd[18717]: new user: name=_chrony, UID=111, GID=115, home=/var/lib/chrony, shell=/usr/sbin/nologin
auth.log:Sep 26 04:55:13 localhost usermod[18723]: change user '_chrony' password
auth.log:Sep 26 04:55:13 localhost chage[18728]: changed password expiry for _chrony
auth.log:Sep 26 04:55:13 localhost chfn[18731]: changed user '_chrony' information
dpkg.log:2019-09-26 04:55:13 install chrony:amd64 <none> 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status half-installed chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 configure chrony:amd64 3.2-4ubuntu4.2 <none>
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status unpacked chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:13 status half-configured chrony:amd64 3.2-4ubuntu4.2
dpkg.log:2019-09-26 04:55:15 status installed chrony:amd64 3.2-4ubuntu4.2
kern.log:Sep 26 04:55:14 localhost kernel: [9630131.911799] audit: type=1400 audit(1569473714.650:59): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/sbinchronyd" pid=18964 comm="apparmor_parser"
syslog:Sep 26 04:55:14 localhost kernel: [9630131.911799] audit: type=1400 audit(1569473714.650:59): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/sbin/chronyd" pid=18964 comm="apparmor_parser"
syslog:Sep 26 04:55:15 localhost systemd[1]: Starting chrony, an NTP client/server...
syslog:Sep 26 04:55:15 localhost chronyd[19064]: chronyd version 3.2 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SECHASH +SIGND +ASYNCDNS +IPV6 -DEBUG)
syslog:Sep 26 04:55:15 localhost chronyd[19064]: Initial frequency -0.501 ppm
syslog:Sep 26 04:55:15 localhost systemd[1]: Started chrony, an NTP client/server.
syslog:Sep 26 04:55:23 localhost chronyd[19064]: Selected source 198.50.238.163

brew cask install chronycontrol