7 Useful Cron Alternatives For Linux

Cron, the traditional Unix job scheduler, has been a cornerstone for automating tasks in Linux systems. However, its limitations, such as the requirement for the system to be constantly running, have led to the development of several alternatives that offer more flexibility and reliability.

1. Anacron

Anacron is a periodic command scheduler designed to handle tasks even when the system is not always running. Unlike cron, which requires the system to be on at the scheduled time, Anacron ensures that tasks are executed the next time the system boots up. This makes it particularly useful for laptops and desktops that are frequently turned off.

To use Anacron, you need to install it via your package manager. For example, on Ubuntu:

sudo apt install anacron

You can then add jobs to the /etc/anacrontab file using the syntax:

period delay-after-computer-start job-identifier command

For instance, to run a daily backup script:

1 15 cron.daily /bin/sh /home/ramces/backup.sh

Anacron is limited to daily, weekly, or monthly schedules, making it less versatile than cron for tasks that need to run more frequently.

2. Cronie

Cronie is a comprehensive cron alternative that includes the anacron package, allowing for both synchronous and asynchronous job scheduling. It provides a complete cron experience with the added benefit of anacron's flexibility.

To install Cronie, you need to download and compile the source code:

wget https://github.com/cronie-crond/cronie/releases/download/cronie-latest/cronie-latest.tar.gz
cd Downloads
tar xvzf cronie-latest.tar.gz
cd cronie-latest/
./configure
make
sudo make install

Once installed, you can manage cron jobs using the standard crontab -e command. Cronie follows the same syntax as cron:

* * * * * /your/command/here

This makes it easy to transition from traditional cron to Cronie.

3. fcron

fcron is another modern alternative to cron, designed to be more flexible and user-friendly. It separates the component functions of cron into their own modules, making it easier to manage and customize.

fcron supports more advanced features such as job dependencies and conditional execution, which are not available in traditional cron. It also includes a built-in editor for creating and managing cron jobs, making it more accessible to users who are not comfortable with the command line.

4. bcron

bcron is a simple and modern cron alternative that aims to provide a suite of software for managing system job scheduling. It separates the functions of cron into distinct components, similar to fcron, but with a focus on simplicity and ease of use.

bcron is particularly useful for users who need a lightweight and easy-to-configure cron alternative. It does not include the complexity of some other alternatives but still offers reliable job scheduling.

5. Systemd Timers

Systemd, the system and service manager for Linux, includes a timer functionality that can be used as an alternative to cron. Systemd timers can trigger events at specified time intervals and offer more flexibility than traditional cron jobs.

To create a systemd timer, you need to create two files: a .timer file and a corresponding .service file. For example, to run a script daily, you would create mytimer.timer and mytimer.service in the /etc/systemd/system directory.

Here is an example of mytimer.timer:

[Unit]
Description=Run my script daily

[Timer]
OnCalendar=daily
Persistent=true

[Install]
WantedBy=timers.target

And mytimer.service:

[Unit]
Description=Run my script

[Service]
ExecStart=/path/to/your/script.sh

Then, enable and start the timer:

sudo systemctl enable mytimer.timer
sudo systemctl start mytimer.timer

Systemd timers can also trigger events based on system events like boot or startup, making them highly versatile.

6. Jobber

Jobber is a lightweight cron alternative that focuses on simplicity and ease of use. It supports the standard cron syntax and can be easily installed and configured.

Jobber is particularly useful for users who need a straightforward cron replacement without the complexity of some other alternatives. It is designed to be easy to set up and manage, making it a good choice for those who are new to job scheduling.

7. mcron

mcron is another cron alternative that offers a simple and reliable way to schedule tasks. It supports the standard cron syntax and includes features like job dependencies and conditional execution.

mcron is known for its stability and ease of use, making it a good choice for users who need a dependable cron replacement. It is also relatively lightweight compared to some other alternatives, which can be beneficial for systems with limited resources.

Additional Considerations

Logging and Monitoring

For users who need detailed logging and monitoring of their scheduled tasks, alternatives like systemd timers and some of the more advanced cron replacements offer better logging capabilities. For example, systemd timers can log execution details, and tools like StackStorm provide extensive logging and monitoring features.

GUI and Web Interfaces

Some users may prefer a graphical user interface (GUI) or web interface for managing their scheduled tasks. Tools like Node-Red and StackStorm offer user-friendly interfaces that make it easier to set up and monitor jobs. These interfaces can be particularly useful for casual users who are not comfortable with command-line interfaces.

Multi-Node Scheduling

For environments with multiple servers, tools like Nomad and Kubernetes CronJobs can manage scheduled tasks across a cluster. These tools provide advanced features for distributed job scheduling and are ideal for complex environments.

By choosing the right cron alternative based on your specific needs, you can ensure that your tasks are executed reliably and efficiently, even in scenarios where traditional cron may fall short.