34
votes
Accepted
chrony vs. systemd-timesyncd – What are the differences and use cases as NTP clients?
The announcement of systemd-timesyncd in the systemd NEWS file does a good job of explaining the differences of this tool in comparison with Chrony and tools like it. (emphasis mine):
A new "systemd-...
- 22.6k
25
votes
Accepted
Set clock to 24 hour format for all users
If you use the date command on the command line, and get back something like Fri 22 Nov 2019 02:47:51 PM EST, then it means your locale settings are currently set to a locale that specifies a 12-hour ...
- 114k
18
votes
chrony vs. systemd-timesyncd – What are the differences and use cases as NTP clients?
As the other answer correctly states, chrony implements NTP and systemd-timesyncd SNTP.
From the point of view of a time service client:
SNTP is a much more simple protocol to implement;
NTP allows ...
- 58k
11
votes
Chrony 3.1 refuses to sync with ntp server
There is a similar bug in RH Bugzilla that was closed as notabug. The issue is a combination of poor time server and a change in defaults for newer chrony to not use them.
https://bugzilla.redhat.com/...
- 111
11
votes
Accepted
In Debian bullseye, does systemd-timesyncd check for other ntp daemons?
The systemd-timesyncd service no longer checks for conflicts itself. Instead, the conflict is handled by having systemd-timesyncd in its own package, which conflicts with other time service packages: ...
- 481k
9
votes
Accepted
Chrony client do not change system and hardware date
Quoting the official FAQ, chronyd will only adjust the clock gradually:
By default, chronyd adjusts the clock gradually by slowing it down or speeding it up. If the clock is too far from the true ...
- 10.8k
6
votes
chrony vs. systemd-timesyncd – What are the differences and use cases as NTP clients?
chrony is not a fork form ntpd but it is implemented from scratch. It implements both client and server modes of full NTPv4 protocol (RFC5905). On enterprise grade users, we are seeing a trend ...
- 173
6
votes
Difference between chronyd and ntpd
The Red Hat documentation here has a good comparison of Chrony and NTP and says "Chrony should be preferred for all systems except for the systems that are managed or monitored by tools that do not ...
- 61
6
votes
Difference between chronyd and ntpd
This site comparing chronyd vs ntpd vs openntpd suggests that chronyd has more flexibility in configuring a slewing settings.
- 136
4
votes
Accepted
Issues Using GPSD as Source for Chronyd
Turns out that gpsd needed the -n flag. I added that in /etc/default/gpsd
-n
Don't wait for a client to connect before polling whatever GPS is associated with it.
Some ...
- 41
3
votes
Accepted
Update time using chrony from systemd script (some app restart)?
The solution is the "+" syntax for the ExecStartPre parameter. The following executes the chronyc executable with root permissions (+) and ignores any errors that may occur for this call (-):...
- 141
3
votes
CentOS 7 timedatectl does not work properly with chronyd
timedatectl works with any ntp client (like chrony). systemd supports systemd-timesyncd from v213 but in latest version of CentOS 7 (I am currently on 7.7.1908) they have decided to disabled it.
If ...
- 465
3
votes
Chrony 3.1 refuses to sync with ntp server
If you have a windows based NTP server, maybe this will be a fix for you (It worked for me in a similar problem):
https://chrony.tuxfamily.org/faq.html
3.4. Using a Windows NTP server? A common issue ...
- 31
3
votes
Chrony 3.1 refuses to sync with ntp server
For chrony 3.1.
We've pieced together a solution based on the following thread, but for a concise, simple to check answer try the following. Check the status of the time sync you receive with ...
- 131
3
votes
system clock synchronized: no
I got the same behaviour.
to solve it, run the follow command as root:
hwclock --systohc
This will synchronize your hardware clock with your system time to make it more precise
- 31
3
votes
Accepted
Chrony on RHEL7.2 can sync to windows ntp server, But Chrony on RHEL7.4 can't sync it
This issue is not considered to be a bug with chrony, so the chrony package on RHEL 7.4 and above will exhibit the same behaviour.
The root cause of the problem is that chrony considers the time ...
- 8,719
3
votes
Chrony sources are with unknown address
I suspect you've resolved this by now - but if anyone else is having the same problem:
SELinux blocks resolver access from chronyd, simply disabling it allows you to test if this is the cause or add ...
- 31
3
votes
Using gpsd and chrony without pulse per second
It should work with the refclock SHM 0 directive alone. SHM 1 and SOCK work only with PPS.
In the gpsd log there is a hint about missing GPRMC message. The receiver needs to be configured to send a ...
- 41
2
votes
Accepted
is it mandatory to configure the allow in chrony.conf
From your formulation, I didn't completely understand where you have added the allow directive in order to make the service work as expected.
To quote from the chrony.conf(5) man page:
allow [all] [...
- 23.6k
2
votes
Accepted
how to test ntp servers as real servers that responding without using ping test
Check the NTP servers with ntpdate tool.
Something like this:
OP=$(ntpdate -q ntp1)
If OP contains Proper Date Data, ntp1 is working. Else try ntp2.
Reference : https://www.tunnelsup.com/how-to-test-...
- 3,385
1
vote
Does having hyperv-daemons enabled show that the system clock is synchronised by timedatectl?
timedatectl gets the synchronization information from systemd-timedated.service.
Depending on the version of systemd-timedated.service, it may be aware of:
only systemd-timesyncd.service,
a built-in ...
- 114k
1
vote
system clock synchronized: no
Couldn't find an answer anywhere. But finally figured it out. Here's how I solve mine:
1 - make sure /etc/chrony.conf is using a pool. E.g. pool 2.almalinux.pool.ntp.org iburst
2 - make sure firewall ...
- 111
1
vote
Accepted
PPS on focal/20.04 timed out and never recovers
In our case there was an issue in the BIOS. An update from our vendor fixed it.
- 121
1
vote
chrony keeps going in future
Your clock is probably running faster than what can be corrected by the kernel. This may be a hardware or kernel issue, e.g. on a virtual machine.
Check the frequency value printed by chronyc tracking....
- 41
1
vote
Why "hwclock -u" is not displaying the time in UTC?
The Hardware Clock does not know its timezone, it's just a clock. So if it's not set to UTC, but to some other specific timezone, you have to provide the timezone yourself.
The -u, --utc option does ...
- 52.1k
1
vote
Creating an isolated NTP server with only 1PPS and no external "time" input (No GPS)
Partially answering my own questions from our own trial and errors.
Questions: 1. Is it possible to feed the 1PPS directly to chrony?
Answer:1 Chrony config uses 2 methods to get PPS:
Get it from ...
- 51
1
vote
Accepted
Automatic time synchronization: `ntpdate` works but `chrony` does not
Your clock was almost certainly synchronised. The "Clock unsynchronised" is misleading as it only applies while ntpd is waiting to synchronise with its upstream sources.
There are two routes ...
- 128k
1
vote
Accepted
Problem with chrony 3.2 syncing to NTP server pools
I solved the problem, and the problem really was a bad mask in a ntpd's restrict directive, effectively causing NTP time queries not to be answered by all but one server.
In addition I had set ...
- 1,771
1
vote
Accepted
chrony synchronitation
Check if chrony is synchronised with commands
You can use chrony specific commands to check the ntp status.
If you want to see the information for the current ntp server use
chronyc tracking
To ...
- 71
1
vote
how to build stable NTP server
If your computers form a completely detached network, and all you want to ensure is that they are synchronized among each other, you don't need a dedicated NTP server but can instead define all ...
- 23.6k
Only top scored, non community-wiki answers of a minimum length are eligible