Introduction

This article describes how to configure MongoDB log rotation to avoid any high disk space consumption by mongo logs.

Description

According to official MongoDB documentation, the MongoDB log rotation is not automatic and must be triggered using one of this ways:

Mongo admin command trigger

1. Launch a mongo shell on admin database
2. Enter the following command

db.adminCommand( { logRotate : 1 } )

Mongo process trigger

1. Send the SIGUSR1 signal to the mongod process

kill -SIGUSR1 `cat /var/lib/mongo/mongod.lock`

Implementation

The second option will be used as we would manage the MongoDB log rotation using embedded logrotate utility.

Start by creating following file:

vi /etc/logrotate.d/mongodb

Then adding this content

/var/log/mongodb/*.log {
  daily
  rotate 5
  compress
  dateext
  missingok
  notifempty
  sharedscripts
  copytruncate
  postrotate
    /bin/kill -SIGUSR1 `cat /var/lib/mongo/mongod.lock 2> /dev/null` 2> /dev/null || true
  endscript
}

Note : The rotate value defines the number of rotations where the compressed logs will be kept on disk before deletion.

The log rotation mechanism can be checked with followed trigger

logrotate -f -v /etc/logrotate.d/mongodb

Automation

The attached ses8-mongodb-logrotate.sh is available to perform the above actions automatically.