chrony operation

ntpq

chronyc sources

amazon linux default config

/etc/chrony.conf

# use the local instance NTP service, if available
server 169.254.169.123 prefer iburst

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
pool 2.amazon.pool.ntp.org iburst

# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift

# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3

# Allow NTP client access from local network.
#allow 192.168.0.0/16

# Specify file containing keys for NTP authentication.
keyfile /etc/chrony.keys

# Specify directory for log files.
logdir /var/log/chrony

# Select which information is logged.
#log measurements statistics tracking

# save data between restarts for fast re-load
dumponexit
dumpdir /var/run/chrony

# use a key to secure communication between chronyc and the daemon
commandkey key1

Support leap-sec ???

Default, NO but...

`leapsecmode` directive

Maybe from ver > 2.x.
RHEL7(cent7) updated to 2.1 https://www.scientificlinux.org/sl-errata/slsa-20152241-3/
RHEL6(cent6) + EPEL ???

leapsecmode slew
maxslewrate 1000
smoothtime 400 0.001 leaponly

Verification

Confirmed