Set date and time Rocky

Introduction

Syncing date and time is an important factor increasing stability and security of all systems.

In this article you can learn how to configure date and time manually. And what is more important - how to sync them with ntp server.

Get current system time

You can get current system time by running date

date

2024-04-20 00:00:01.364911+02:00

Get current BIOS date and time

You can get current BIOS date and time by running hwclock

sudo hwclock

2024-04-20 01:33:46.389911+02:00

date и hwclock can show absolutely different time

Change current date

You can set date by running date

date MMDDhhmmCCYY.ss

If you use «date MMDDhhmmCCYY» without seconds, ss is set to 00.

After setting date this new time should be enetered to BIOS:

hwclock --systohc

To check if changes are saved run

sudo hwclock

Sync with ntp

chrony is used as ntp server and client in Rocky

which chronyd

/usr/sbin/chronyd

If chrony is not installed run

sudo yum install -y chrony

To check if chronyd is starting after boot execute

systemctl list-unit-files | grep chronyd.s

chronyd.service disabled

If chronyd is disabled execute

systemctl start chronyd
systemctl enable chronyd

To check if ntp service is added to Firewall public zone execute

sudo firewall-cmd --get-services | grep ntp

If it is not allowed yet you can allow UDP traffic for ntp by executing

firewall-cmd --permanent --add-service=ntp
firewall-cmd --reload

success
success

Edit chrony.conf file with server configurations

vi /etc/chrony.conf

Search for your timezone at www.ntppool.org

I have found Helsinki and added

server 0.fi.pool.ntp.org server 1.fi.pool.ntp.org server 2.fi.pool.ntp.org server 3.fi.pool.ntp.org

Restart ntpd

systemctl restart ntpd

Set BIOS time to system time

hwclock --systohc

Force Rocky to sycn time with ntp server

You can use the following command

chronyc makestep

To allow everything that can be allowed use

sudo sed -i 's/#allow/allow/' /etc/chrony.conf

Check chronyd status

systemctl status chronyd

● chronyd.service - NTP client/server Loaded: loaded (/usr/lib/systemd/system/chronyd.service; disabled; vendor preset: enabled) Active: inactive (dead) Docs: man:chronyd(8) man:chrony.conf(5)

Start chronyd

systemctl start chronyd

● chronyd.service - NTP client/server Loaded: loaded (/usr/lib/systemd/system/chronyd.service; disabled; vendor preset: enabled) Active: active (running) since Wed 2021-09-01 19:39:43 EEST; 19s ago Docs: man:chronyd(8) man:chrony.conf(5) Process: 2878 ExecStartPost=/usr/libexec/chrony-helper update-daemon (code=exited, status=0/SUCCESS) Process: 2874 ExecStart=/usr/sbin/chronyd $OPTIONS (code=exited, status=0/SUCCESS) Main PID: 2876 (chronyd) Tasks: 1 (limit: 23548) Memory: 788.0K CGroup: /system.slice/chronyd.service └─2876 /usr/sbin/chronyd Apr 20 01:33:46 localhost.localdomain systemd[1]: Starting NTP client/server... Apr 20 01:33:46 localhost.localdomain chronyd[2876]: chronyd version 3.5 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SIGND +ASYNCDNS +SECHASH +IPV6 +DEBUG) Apr 20 01:33:46 localhost.localdomain chronyd[2876]: Using right/UTC timezone to obtain leap second data Apr 20 01:33:46 localhost.localdomain systemd[1]: Started NTP client/server. Apr 20 01:33:46 localhost.localdomain chronyd[2876]: Selected source 162.159.200.123 Apr 20 01:33:46 localhost.localdomain chronyd[2876]: System clock TAI offset set to 37 seconds

Stop chronyd

systemctl stop chronyd

Restart chronyd

systemctl restart chronyd

tracking: check sync

To check if sync is working run

chronyc tracking

Reference ID : 4E2412B8 (78-36-18-184.dynamic.murmansk.dslavangard.ru) Stratum : 2 Ref time (UTC) : Sat Apr 20 01:33:46 2024 System time : 0.000049305 seconds fast of NTP time Last offset : -0.000010323 seconds RMS offset : 0.000790649 seconds Frequency : 4.357 ppm fast Residual freq : +0.154 ppm Skew : 1.831 ppm Root delay : 0.034635838 seconds Root dispersion : 0.000497150 seconds Update interval : 64.6 seconds Leap status : Normal

Comments: Reference ID – the reference ID and name to which the computer is currently synced. Stratum – number of hops to a computer with an attached reference clock. Ref time – this is the UTC time at which the last measurement from the reference source was made. System time – delay of system clock from synchronized server. Last offset – estimated offset of the last clock update. RMS offset – long term average of the offset value. Frequency – this is the rate by which the system’s clock would be wrong if chronyd is not correcting it. It is provided in ppm (parts per million). Residual freq – residual frequency indicated the difference between the measurements from reference source and the frequency currently being used. Skew – estimated error bound of the frequency. Root delay – total of the network path delays to the stratum computer, from which the computer is being synced. Leap status – this is the leap status which can have one of the following values – normal, insert second, delete second or not synchronized. To check information about chrony’s sources, you can issue the following command.

Configure chronyd

sudo vi /etc/chrony.conf

# Use public servers from the pool.ntp.org project. # Please consider joining the pool (http://www.pool.ntp.org/join.html). pool 2.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 # Enable kernel synchronization of the real-time clock (RTC). rtcsync # Enable hardware timestamping on all interfaces that support it. #hwtimestamp * # Increase the minimum number of selectable sources required to adjust # the system clock. #minsources 2 # Allow NTP client access from local network. #allow 192.168.0.0/16 # Serve time even if not synchronized to a time source. #local stratum 10 # Specify file containing keys for NTP authentication. keyfile /etc/chrony.keys # Get TAI-UTC offset and leap seconds from the system tz database. leapsectz right/UTC # Specify directory for log files. logdir /var/log/chrony # Select which information is logged. #log measurements statistics tracking

Timezone

Get current timezone

timedatectl

Local time: Fri 2021-05-21 01:42:44 MDT Universal time: Fri 2021-05-21 07:42:44 UTC RTC time: Fri 2021-05-21 07:42:43 Time zone: America/Denver (MDT, -0600) NTP enabled: yes NTP synchronized: yes RTC in local TZ: no DST active: yes Last DST change: DST began at Sun 2021-03-14 01:59:59 MST Sun 2021-03-14 03:00:00 MDT Next DST change: DST ends (the clock jumps one hour backwards) at Sun 2021-11-07 01:59:59 MDT Sun 2021-11-07 01:00:00 MST

Change timezone with set-timezone command

timedatectl set-timezone "Europe/Helsinki"

Check the result

timedatectl | grep "Time zone"

Time zone: Europe/Helsinki (EEST, +0300)