In V8 user=odoo, try this:

chown odoo  /var/log/openerp/openerp-server.log

and you add (or other handler):

log_handler = ["[':INFO']"]

I do this but still not working

ls -l commande send this information:

[user@localhost openerp ] # ls -l

-rw-r--r--. 1 odoo root 0 Jan 28 15:25 openerp-server.log

and ther is my odoo config:

[options]
; This is the password that allows database operations:
admin_password=#####
db_host=localhost
db_port=5432
db_user=######
db_password=#######
addons_path=/usr/lib/python2.7/site-packages/openerp-8.0_c7d8e97-py2.7.egg/openerp/addons/
logfile=/var/log/openerp/openerp-server.log
log_handler=["[':INFO']"]
log_level=info

and whene i execute systemctl status openerp.service i got that

.................

python /usr/local/bin/openerp-server -c /etc/openerp-server.conf --pid=/run/openerp/openerp-server.pid --syslog

...................

Any help please !!!!!

Perhaps useful for others because this question was asked a long time ago.

In your configuration file add the following lines:

# Logging
log_handler = werkzeug:WARNING, :INFO
log_level = info
logfile = /var/log/odoo/odoo.log
logrotate = True

(Change settings as you seem fit. The following URL provides a list of command line parameters which can be used in the configuration file as well: https://odoo-development.readthedocs.io/en/latest/admin/log-handler.html)

It's important that the user under which odoo runs has write permissions to the directory where the log files are stored. In my case it runs as user odoo16 member of group odoo16. So using sudo or as root create a log directory for odoo as follows:

# mkdir /var/log/odoo

# chown root:odoo16 /var/log/odoo

# chmod 775 /var/log/odoo

# ls -l /var/log

drwxrwxr-x 2 root odoo16 4096 Oct 28 16:54 odoo

The result should be as above. Next restart your odoo service, odoo16 in my case.

# systemctl restart odoo16

please can you give more details i hve a same issue when i check my odoo status i got this error 

/odoo.service; disabled; vendor preset: enabled)
since Wed 2021-09-01 16:45:57 UTC; 36min ago
odoo/odoo-bin -c /etc/odoo-server.conf (code=exited, status=2)
=2)
 Started Odoo.
4541]: Usage: odoo-bin [options]
4541]: odoo-bin: error: The config file '/etc/odoo-server.conf' selected with -c/--config doesn't exist or is not readable, use -s/--save if you want to gen>
 odoo.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
 odoo.service: Failed with result 'exit-code'.