MongoDB service doesn't start. errno:13 Permission denied

Question

I have installed MongoDB on a Ubuntu server like is indicated in the docs http://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/. Then, I have modified the configuration file /etc/mongod.conf for, later, run a mongod service.

MongoDB runs correctly if I execute:

sudo mongod -f /etc/mongod.conf

But MongoDB stops if I execute:

sudo service mongod start

In the config file /etc/mongod.conf I changed only this:

dbpath=/data/db
logpath=/root/logs/mongod.log
port=20000

With this configuration, the log file is not created too.

If I don't modify the previous values indicated, the service starts correctly. The default values are:

dbpath=/var/lib/mongodb
logpath=/var/log/mongodb/mongod.log
port = 27017

Because the log file is not created with the custom configuration, I have only changed the dbpath for see the error:

[initandlisten] exception in initAndListen: 10309 Unable to create/open lock file: /data/db/mongod.lock errno:13 Permission denied Is a mongod instance already running?

I tried to run the following commands but without success:

sudo chown -R `id -u` /data/db

sudo rm /var/lib/mongodb/mongod.lock
mongod --repair

Stack:

• Ubuntu 14.10
• MongoDB 2.6.5

Answer 1

We must make all the directories/files owned by mongod user. For this:

sudo chown -R mongodb:mongodb /data/db

Answer 2

I found a special case where the use of symlinks appears to fail:

Using a standard enterprise install of mongodb except I changed the /var/lib/mongodb to a symlink as I wanted to use an XFS filesystem for my database folder and a third filesystem for the log folder.

$sudo systemctl start mongod (fails with a message no permission to write to mongodb.log).. but it succceded if I started with the same configuration file:

.. as the owner of the external drives (ziggy) I was able to start $mongod --config /etc/mongodb.conf --fork

I eventually discovered that .. the symlinks pointed to a different filesystem and the mongodb (user) did not have permission to browse the folder that the symlink referred. Both the symlinks and the folders the symlinks referred had expansive rights to the mongod user so it made no sense?