os.getlogin() returns the user logged in on the controlling terminal. However
'crontab' only looks for the login name of the process' real user id which
pwd.getpwuid(os.getuid())[0] does provide.
While in most cases there is no difference, the former might fail under certain
circumstances (e.g. a lxc container connected by attachment without login),
throwing the error 'OSError: [Errno 25] Inappropriate ioctl for device'.
Currently, when writing user's crontab, ansible calls
crontab <file> -u <user>
This is incorrect according to crontab(1) on both FreeBSD and Linux,
which suggest that file argument should be the last.
At least on FreeBSD, this leads to incorrect cron module bahavior which
writes to root's crontab instead of users's
Support specifying an absolute path (typically /etc/crontab) rather than
a path relative to /etc/cron.d, to allow modifying the main system crontab.
Particularly useful for target systems that have /etc/crontab but no
/etc/cron.d.
I have a task like this in a playbook. The ansible_ssh_user is 'root'
for this host.
- cron:
hour: 00
job: /home/backup/backup.sh
name: baserock.org data backup
user: backup
Running it gave me the following error:
TASK: [backup cron job, runs every day at midnight] ***************************
failed: [baserock-backup1] => {"failed": true}
msg: crontab: can't open '/tmp/crontabvVjoZe': Permission denied
crontab: user backup cannot read /tmp/crontabvVjoZe
The temporary file created by the 'cron' module is created with the
Python tempfile.mkstemp() function. This creates a file that is readable
only by 'root' (mode 600). The Busybox `crontab` program then checks if
the file is readable by the 'backup' user, and fails if it isn't. So we
need to make sure the file is world-readable before running `crontab`.