This topic describes how to connect to a replica set instance by using the mongo shell, which is a database management tool provided with MongoDB. You can install the mongo shell on your client or in an ECS instance.

Prerequisites

Procedure

  1. Log on to the ApsaraDB for MongoDB console.
  2. In the upper-left corner of the page, select the region where the target instance resides.
  3. In the left-side navigation pane, click Replica Set Instances.
  4. Find the target instance and click its ID.
  5. In the left-side navigation pane, click Database Connection to obtain the connection addresses of a node.
    Note For more information about the connection addresses, seeIntroduction to connection addresses.
  6. Connect to the replica set instance from your client or ECS instance that has the mongo shell installed.
    • Single-node connection

      During regular tests, you can directly connect to a primary or secondary node. Note that a failover changes the roles of connected nodes, which affects read/write operations.

      Command format:

      mongo --host <host> -u <username> -p --authenticationDatabase <database>
      Note
      • <host>: the connection string of the primary or secondary node.
        • Primary node: If you connect to this node, you can perform read/write operations on the databases of the replica set instance.
        • Secondary node: If you connect to this node, you can only perform read operations on the databases of the replica set instance.
      • <username>: the username you use to log on to a database of the replica set instance. The initial username is root. We recommend that you do not log on to a database as the root user in a production environment. You can create users and grant permissions to them as needed. For more information, see Manage MongoDB users though DMS.
      • <database>: the name of the authentication database. It is the database where the database user is created. If the database username is root, enter admin.

      Example:

      mongo --host dds-bp**********.mongodb.rds.aliyuncs.com:3717 -u root -p --authenticationDatabase admin
      When Enter password: is displayed, enter the password of the database user and press Enter. If you forget the password of the root user, you can reset it. For more information, see Set a password for a replica set instance.
      Note The password you enter is not displayed.
    • HA connection (recommended): You can use a connection string URI to connect to both the primary and secondary nodes of a replica set instance. This guarantees that your application is always connected to the primary node and the read/write operations of your application are not affected even if the roles of the primary and secondary nodes are switched.
      Command format:
      mongo "<ConnectionStringURI>"
      Note
      • The connection string URI must be enclosed in a pair of double quotation marks ("").
      • <ConnectionStringURI>: the Connection String URI of the replica set instance.

        You must replace **** in the Connection String URI with the database password. For more information about how to set a database password, see Set a password for a replica set instance.

Common connection scenarios

FAQ