armbian-truncate-logs and PostgreSQL

[Tim Makarios]

One of my Armbian machines (24.5.5 bookworm) is running PostgreSQL.  I don't think I've changed any of its default settings relating to PostgreSQL's log files or their permissions, but I'm occasionally getting emails from the armbian-truncate-logs cron job saying:

Quote

truncate: cannot open '/var/log/postgresql/postgresql-15-main.log' for writing: Permission denied

The directory /var/log/postgresql is owned by root (and group postgres) and has permissions drwxrwxr-t, and the file /var/log/postgresql/postgresql-15-main.log is owned by postgres (and group adm) and has permissions -rw-r-----.

 

In /var/log.hdd/postgresql the ownership and permissions are the same, and there are also files postgresql-15-main.log.1, postgresql-15-main.log.2.gz, postgresql-15-main.log.3.gz, ..., postgresql-15-main.log.10.gz (with the same ownership and permissions as postgresql-15-main.log).  The file postgresql-15-main.log.1 is a prefix of postgresql-15-main.log.

 

I have this problem only with PostgreSQL's logs; armbian-truncate-logs doesn't complain about any other log files.

 

Is there something I need to do to fix this, or is this a bug that will be fixed in future?

[Tim Makarios]

I seem to have successfully worked around this problem by changing the permissions on /var/log/postgresql.  I'm not sure why the cron job, which looks like it's set up to run as root, couldn't truncate the file in that folder; and I'm not sure whether my solution is durable, or whether a reboot or something might reset the permissions at some stage, but it works for now.

[Tim Makarios]

It does, indeed, seem to have reverted to the problematic permissions after a reboot.