Description of problem:
logrotate for mongodb logrotate file creates an additional file

How reproducible:
always

Steps to Reproduce:
1. Run "logrotate -f /etc/logrotate.conf"

Actual results:
mongodb logrotate creates two files.

Expected results:
The logrotate should only create one file.

Additional info:

ls looks as follows:

-rw-r--r--.  1 mongodb mongodb    0 Jan 11 18:35 mongod.log
-rw-r--r--.  1 mongodb mongodb 1168 Dec 20 03:06 mongod.log-20151220.gz
-rw-r--r--.  1 mongodb mongodb  493 Dec 27 03:40 mongod.log-20151227.gz
-rw-r--r--.  1 mongodb mongodb  493 Jan  3 13:37 mongod.log-20160103.gz
-rw-r--r--.  1 mongodb mongodb 2843 Jan 11 18:35 mongod.log-20160111
-rw-r--r--.  1 mongodb mongodb    0 Dec 20 03:06 mongod.log.2015-12-20T02-06-01
-rw-r--r--.  1 mongodb mongodb    0 Dec 27 03:40 mongod.log.2015-12-27T02-40-01
-rw-r--r--.  1 mongodb mongodb    0 Jan  3 13:37 mongod.log.2016-01-03T12-37-01

This is due to mongodb having its own logrotate on SIGUSR1 signal.
As we have "copyontruncate" set, the USR1 is not needed.

So we could just remove the postrotate action from the logrotate:

# cat /etc/logrotate.d/mongodb 
/var/log/mongodb/*.log {
       weekly
       rotate 10
       copytruncate
       delaycompress
       compress
       notifempty
       missingok
==>       postrotate
==>          /bin/kill -USR1 `cat /var/run/mongodb/mongod.pid 2>/dev/null` 2> /dev/null|| true
==>       endscript
}

See also https://docs.mongodb.com/v2.6/reference/command/logRotate/ for some additional information.