Easy Steps To Set up Time Synchronization on AlmaLinux 9

In this guide, we aim to illustrate How To Set up Time Synchronization on AlmaLinux 9. Computer time synchronization is crucial for maintaining accurate and consistent timestamps across your systems. The real-time clocks within computers are prone to drift, just like any other timekeeping device. This drift can lead to inconsistencies, particularly in networked environments.

Therefore, protocols have been designed specifically to maintain time coordination across networked computers. The Network Time Protocol (NTP) and Precision Time Protocol (PTP) are two of the most prominent protocols used to synchronize system time.

These protocols work by distributing timestamps between one or more master clocks and time clients. Follow the steps below to learn how to Sync Time on AlmaLinux 9.

To configure time synchronization, you’ll need to log in to your AlmaLinux 9 server as a non-root user with sudo privileges. If you haven’t already done so, refer to our guide on Initial Server Setup with AlmaLinux 9 for instructions.

Now, let’s dive into the steps to Sync Time on AlmaLinux 9.

1. Check the Time Zone And Clock on AlmaLinux 9

The most basic command to determine the current time on your server is date. Any user can execute the following command to check the date and time on AlmaLinux 9:

sudo date

**Output**
Tue Jan  3 09:29:40 AM EDT 2023

Note: In many cases, your server will default to the UTC time zone. UTC, or Coordinated Universal Time, represents the time at zero degrees longitude. Employing Universal Time minimizes potential confusion when your infrastructure spans multiple time zones.

2. Change the Time Zone on AlmaLinux 9

If you have specific requirements and need to modify the time zone on your AlmaLinux 9 server, you can utilize the timedatectl command. First, list the available time zones on AlmaLinux 9 using the following command:

sudo timedatectl list-timezones

The output will display a comprehensive list of available time zones on AlmaLinux 9.

Once you’ve identified the correct time zone, use the following command to set it:

sudo timedatectl set-timezone America/New_York

Remember to replace America/New_York with the appropriate time zone from the list.

Now that you know how to check the time zone and clock on AlmaLinux 9, let’s proceed with installing and starting NTP.

3. Install Chrony and NTP on AlmaLinux 9

To install NTP on your server, you need to have Chrony installed. Chrony is an implementation of the Network Time Protocol (NTP) and offers various benefits.

sudo dnf install chrony -y

Next, start and enable the Chrony service using the following commands:

# sudo systemctl start chronyd
# sudo systemctl enable chronyd

Verify that the Chrony service is active and running on your server by running the command below:

sudo systemctl status chronyd

[Image of Chrony Service Status on AlmaLinux 9]

If everything went as expected, your date and time should now be synchronized from the NTP Server on AlmaLinux 9. You can confirm your timezone with the following command:

timedatectl

[Image of Time Synchronization Status on AlmaLinux 9]

"NTP synchronized: yes" indicates that the time on AlmaLinux 9 has been successfully synchronized. "NTP enabled: yes" means that the timesyncd service is enabled and running.

For more detailed instructions on setting up an NTP server and client, refer to our guide on Installing NTP Server and Client on AlmaLinux 9.

Alternative Solutions for Time Synchronization on AlmaLinux 9

While Chrony is the recommended and commonly used method for time synchronization, let’s explore alternative approaches to achieve the same goal of accurate timekeeping on AlmaLinux 9.

1. Using systemd-timesyncd (without Chrony):

systemd-timesyncd is a lightweight NTP client built into systemd, which is the system and service manager for most modern Linux distributions, including AlmaLinux 9. It’s designed for basic time synchronization and is often sufficient for systems that don’t require the advanced features of Chrony.

Explanation: systemd-timesyncd operates by periodically querying NTP servers and adjusting the system clock to match. It automatically handles time zone adjustments and can be configured through the timesyncd.conf file.
Steps to Configure and Use systemd-timesyncd:
1. Ensure systemd-timesyncd is enabled: While typically enabled by default, confirm its status:
```
sudo systemctl status systemd-timesyncd
```
  If it’s not running, start and enable it:
```
sudo systemctl start systemd-timesyncd
sudo systemctl enable systemd-timesyncd
```
2. Configure NTP Servers (optional): If you want to use specific NTP servers instead of the default ones, edit the /etc/systemd/timesyncd.conf file:
```
sudo nano /etc/systemd/timesyncd.conf
```
  Uncomment the [Time] section and modify the NTP= line to specify your desired NTP servers (comma-separated):
```
[Time]
NTP=pool.ntp.org,time.google.com
```
  Save the file and restart the systemd-timesyncd service:
```
sudo systemctl restart systemd-timesyncd
```
3. Verify Synchronization: After a few minutes, check the synchronization status:
```
timedatectl status
```
  Look for "NTP synchronized: yes" in the output.
Benefits:
- Lightweight and minimal dependencies.
- Easy to configure for basic time synchronization.
- Integrated into systemd, making it a natural choice for system management.
Drawbacks:
- Fewer advanced features compared to Chrony (e.g., no support for hardware time stamping).
- Not suitable for environments requiring high-precision time synchronization.

2. Manual Time Synchronization using ntpdate (one-time synchronization):

While not a continuous synchronization solution like Chrony or systemd-timesyncd, the ntpdate utility allows for a one-time synchronization of the system clock with an NTP server. This can be useful for initial setup or when other synchronization methods are temporarily unavailable. Setting up Time Synchronization on AlmaLinux 9 is not always straightforward.

Explanation: ntpdate queries the specified NTP server, calculates the time difference, and adjusts the system clock accordingly. It’s a quick and simple way to synchronize time manually.
Steps to Use ntpdate:
1. Install ntpdate:
```
sudo dnf install ntpdate -y
```
2. Synchronize Time: Use the following command to synchronize the time with an NTP server:
```
sudo ntpdate pool.ntp.org
```
  Replace pool.ntp.org with your preferred NTP server.
3. Verify Time: Check the system time using the date command:
```
date
```
Important Considerations:
- ntpdate abruptly adjusts the system clock, which can cause issues for some applications.
- It’s not a continuous synchronization solution; you’ll need to run it periodically or schedule it using cron.
- It’s generally recommended to use Chrony or systemd-timesyncd for continuous time synchronization.
Example of Cron job for ntpdate

Edit the crontab:
```
crontab -e
```
Add the following line to run ntpdate daily at 3:00 AM:
```
0 3 * * * /usr/sbin/ntpdate pool.ntp.org
```
This makes sure to update the time daily.

Conclusion

In this guide, you have learned how to view the system time, change time zones, and sync your time using Chrony. Time synchronization in AlmaLinux 9 is vital for ensuring accurate system time across servers, preventing issues with logs, authentication, and scheduled tasks. We’ve also explored alternative methods like systemd-timesyncd and ntpdate for different scenarios. Choosing the right method for Easy Steps To Set up Time Synchronization on AlmaLinux 9 depends on your specific needs and environment. Easy Steps To Set up Time Synchronization on AlmaLinux 9 helps maintain an accurate and reliable system.

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