Problem Description

Check the log (/var/log/mongodb/mongodb.log) for the following information

Wiredtiger error(13).....file:WiredTiger.wt,connection:/var/lib/mongodb/WiredTiger.turtle:handle-open:open:Permission denied

the cause of the problem

• 1. Permission problem.

service mongod startThe default user used at startup is, you mongodbcan view system files ( /lib/systemd/system/mongod.service)

which contains

[Service]
User=mongodb
Group=mongodb

Then in view( /var/lib/mongodb/WiredTiger.turtle) file permissions, use the command

cd /var/libls -l /var/lib/mongodb

View permission discovery  WiredTiger.turtleand the permissions of several other files are root

Therefore, because the permissions of the mogodb user cannot access files under root permissions, the service fails to start.

But why do the permissions of these files become root?

My reason is that I have used the root user to operate the database (using the mongod command under rootx, etc.), which caused the permissions of the file to change and can no longer be used (service mongod start).

solution

Option One:

# storage.dbPath
chown -R mongodb:mongodb /var/lib/mongodb

# systemLog.path
sudo chown -R mongodb:mongodb /var/log/mongodb

Change the data file permissions backmongodb

Then you can start  service mongo startit again, but if you operate the database as the root user, the above problems will still occur. At the same time, it is highly recommended not to use the database under the root user.

Option 2 (not recommended for security reasons):

Revise

/lib/systemd/system/mongod.service

In useris root, Groupfor root.

then start again service mongod start