Anacron
Run missed cron jobs when the system starts
What is Anacron?
Anacron is a complement to traditional cron designed for machines that are not running 24/7. While cron silently skips any job whose scheduled time passes while the system is off, anacron tracks the last execution date of each job and runs missed tasks the next time the machine boots. It stores timestamps in /var/spool/anacron and checks them against the configured period (daily, weekly, monthly) on startup.
Anacron is included by default in most Linux distributions and is typically invoked by cron itself or by systemd at boot. It only supports daily-or-longer intervals — it cannot schedule jobs that need to run hourly or every few minutes. Jobs are defined in /etc/anacrontab with a period in days, a delay in minutes, a unique identifier, and the command to run.
Best For
- Laptops and desktops that are powered off overnight
- Daily maintenance scripts like log rotation and package updates
- Weekly or monthly system cleanup tasks on workstations
- Environments where missed-job recovery is more important than exact timing
Limitations
- Cannot schedule jobs more frequently than once per day
- No sub-minute or even sub-hour precision — daily is the minimum interval
- Only runs as root by default, limiting multi-user scheduling
- No built-in monitoring, alerting, or retry logic for failed jobs
Anacron vs CronJobPro
Anacron solves the missed-job problem on machines that power off, but it cannot replace a full scheduling solution. It lacks any form of monitoring, alerting, or HTTP triggering. CronJobPro runs on reliable cloud infrastructure that is always online, so missed jobs are never an issue. It also provides automatic retries, execution logs, and multi-channel notifications — none of which anacron offers.
Official Website
https://sourceforge.net/projects/anacron/Frequently Asked Questions
What is Anacron?
Anacron is a complement to traditional cron designed for machines that are not running 24/7. While cron silently skips any job whose scheduled time passes while the system is off, anacron tracks the last execution date of each job and runs missed tasks the next time the machine boots. It stores timestamps in /var/spool/anacron and checks them against the configured period (daily, weekly, monthly) on startup.
What is Anacron best for?
Laptops and desktops that are powered off overnight. Daily maintenance scripts like log rotation and package updates. Weekly or monthly system cleanup tasks on workstations. Environments where missed-job recovery is more important than exact timing.
How does Anacron compare to an external cron service?
Anacron solves the missed-job problem on machines that power off, but it cannot replace a full scheduling solution. It lacks any form of monitoring, alerting, or HTTP triggering. CronJobPro runs on reliable cloud infrastructure that is always online, so missed jobs are never an issue. It also provides automatic retries, execution logs, and multi-channel notifications — none of which anacron offers.
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