Briefly explain chrony
chrony linux7 is time to start using the synchronous service, the system built. Faster than ntp, simple
Contains the server and client: a service called chronyd, client tools chronyc
Profile /etc/chron.conf
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 192.168.102.131 iburst
This is the time source address
After modifications need to restart the service, and then view the situation with synchronous chronyc sources -v
[root@student ~]# chronyc sources -v
210 Number of sources = 1
.-- Source mode '^' = server, '=' = peer, '#' = local clock.
/ .- Source state '*' = current synced, '+' = combined , '-' = not combined,
| / '?' = unreachable, 'x' = time may be in error, '~' = time too variable.
|| .- xxxx [ yyyy ] +/- zzzz
|| Reachability register (octal) -. | xxxx = adjusted offset,
|| Log2(Polling interval) --. | | yyyy = measured offset,
|| \ | | zzzz = estimated error.
|| | | \
MS Name/IP address Stratum Poll Reach LastRx Last sample
================================================== =============================
? 192.168.102.131 0 8 0 - + 0ns [+ 0ns] +/- 0ns
This is a server fails, the time is not synchronized feedback
[root@student ~]# chronyc sources -v
210 Number of sources = 1
.-- Source mode '^' = server, '=' = peer, '#' = local clock.
/ .- Source state '*' = current synced, '+' = combined , '-' = not combined,
| / '?' = unreachable, 'x' = time may be in error, '~' = time too variable.
|| .- xxxx [ yyyy ] +/- zzzz
|| Reachability register (octal) -. | xxxx = adjusted offset,
|| Log2(Polling interval) --. | | yyyy = measured offset,
|| \ | | zzzz = estimated error.
|| | | \
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^* 192.168.102.131 3 6 17 13 +5813ns[ +120us] +/- 41ms
This is a normal feedback synchronization
In theory, as long as the service is installed, the configuration file right, had to restart the service, shut down the selinux and firewalld, network communication, it would be to be synchronized, this can not be synchronized.
It was found that chrony version of the client results in higher than chrony version of the server, all updated to the latest version immediately synchronized