Run-time Database Configuration

Configure the Database

Consider the following basic configuration:

processManagement:
   fork: true
net:
   bindIp: 127.0.0.1
   port: 27017
storage:
   dbPath: /var/lib/mongo
systemLog:
   destination: file
   path: "/var/log/mongodb/mongod.log"
   logAppend: true
storage:
   journal:
      enabled: true

For most standalone servers, this is a sufficient base configuration. It makes several assumptions, but consider the following explanation:

• fork is true, which enables a daemon mode for mongod, which detaches (i.e. “forks”) the MongoDB from the current session and allows you to run the database as a conventional server.

• bindIp is 127.0.0.1, which forces the server to only listen for requests on the localhost IP. Only bind to secure interfaces that the application-level systems can access with access control provided by system network filtering (i.e. “firewall”).

• port is 27017, which is the default MongoDB port for database instances. MongoDB can bind to any port. You can also filter access based on port using network filtering tools.

  Note

  UNIX-like systems require superuser privileges to attach processes to ports lower than 1024.

• quiet is true. This disables all but the most critical entries in output/log file, and is not recommended for production systems. If you do set this option, you can use setParameter to modify this setting during run time.

• dbPath is /var/lib/mongo, which specifies where MongoDB will store its data files.

  If you installed MongoDB on Linux using a package manager, such as yum or apt, the /etc/mongod.conf file provided with your MongoDB installation sets the following default dbPath, depending on your Linux distro:

  Platform	Package Manager	Default dbPath
  RHEL / CentOS and Amazon	yum	/var/lib/mongo
  SUSE	zypper	/var/lib/mongo
  Ubuntu and Debian	apt	/var/lib/mongodb
  macOS	brew	/usr/local/var/mongodb

  The user account that mongod runs under will need read and write access to this directory.

• systemLog.path is /var/log/mongodb/mongod.log which is where mongod will write its output. If you do not set this value, mongod writes all output to standard output (e.g. stdout.)

• logAppend is true, which ensures that mongod does not overwrite an existing log file following the server start operation.

• storage.journal.enabled is true, which enables journaling. Journaling ensures single instance write-durability. 64-bit builds of mongod enable journaling by default. Thus, this setting may be redundant.

Given the default configuration, some of these values may be redundant. However, in many situations explicitly stating the configuration increases overall system intelligibility.

Security Considerations

The following configuration options are useful for limiting access to a mongod instance:

net:
   bindIp: 127.0.0.1,10.8.0.10,192.168.4.24,/tmp/mongod.sock
security:
   authorization: enabled

net.bindIp

This example provides four values to the bindIp option:

• 127.0.0.1, the localhost interface;
• 10.8.0.10, a private IP address typically used for local networks and VPN interfaces;
• 192.168.4.24, a private network interface typically used for local networks; and
• /tmp/mongod.sock, a Unix domain socket path.

Because production MongoDB instances need to be accessible from multiple database servers, it is important to bind MongoDB to multiple interfaces that are accessible from your application servers. At the same time it’s important to limit these interfaces to interfaces controlled and protected at the network layer.

security.authorization

Setting this option to true enables the authorization system within MongoDB. If enabled you will need to log in by connecting over the localhost interface for the first time to create user credentials.

Replication and Sharding Configuration

replication:
   replSetName: set0

security:
   keyFile: /srv/mongodb/keyfile