crontab - More than 1000 entries in crontab file, can't install

This document (000020338) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 15 SP3
SUSE Linux Enterprise Server 15 SP2
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 12 SP4 (LTSS)

Situation

After 1000 entries/lines in a crontab file the next attempt to edit and add a new line results in the following error:

# crontab -e
crontab: installing new crontab
More than 1000 entries in crontab file, can't install.
Do you want to retry the same edit?

# crontab -u root /root/1005cron_entries_file
More than 1000 entries in crontab file, can't install.

Attempting to manually install a user crontab with cp /root/1005cron_entries_file /var/spool/cron/tabs/root results in system log errors.

2021-07-21T05:10:01.190514-06:00 sles15sp3 cron[1619]: (CRON) too many entries (/var/spool/cron/tabs/root) 2021-07-21T05:10:01.190637-06:00 sles15sp3 cron[1619]: (root) FAILED (loading cron table)

One of the following cronie RPM package versions has been installed.

SLES12 cronie-1.4.11-59.13.1
SLES15 cronie-1.5.1-6.12.2

Resolution

Some applications need to create more than 1000 entries to a crontab, so the maximum will be increased.

The SLES12 SP5 and SLES15 SP3 and SP2 cron packages released September/2021 include the patch that increases the limit.

Work Around
To work around the issue, create your user crontab file in /etc/cron.d. For example,

# cat /etc/cron.d/bigcron
SHELL=/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/bin:/usr/sbin

0 0 * * * root echo 1
0 0 * * * root echo 2
0 0 * * * root echo 3
0 0 * * * root echo 4
...
0 0 * * * root echo 1002
0 0 * * * root echo 1003
0 0 * * * root echo 1004
0 0 * * * root echo 1005

Cause

Due to security reasons the number of entries in the crontab file needed to be limited to 1000 entries.
The maximum number allowed was set a bit too low.

Disclaimer

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