Help Center/ Document Database Service/ Getting Started/ Getting Started with Replica Sets/ Connecting to a Replica Set Instance/ Connecting to a Replica Set Instance over a Private Network/ Connecting to a Replica Set Instance Using Mongo Shell (Private Network)
Updated on 2024-09-25 GMT+08:00
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Connecting to a Replica Set Instance Using Mongo Shell (Private Network)

Mongo shell is the default client for the MongoDB database server. You can use Mongo Shell to connect to DB instances, and query, update, and manage data in databases. DDS is compatible with MongoDB. Mongo Shell is a part of the MongoDB client. To use Mongo Shell, download and install the MongoDB client first, and then use the Mongo shell to connect to the DB instance.

By default, a DDS instance provides a private IP address. If your applications are deployed on an ECS and are in the same region and VPC as DDS instances, you can connect to DDS instances using a private IP address to achieve a fast transmission rate and high security.

This section describes how to use Mongo Shell to connect to a replica set instance over a private network.

The MongoDB client can connect to an instance with an unencrypted connection or an encrypted connection (SSL). To improve data transmission security, connect to instances using SSL.

Prerequisites

  1. For details about how to create and log in to an ECS, see Purchasing an ECS and Logging In to an ECS.
  2. Install the MongoDB client on the ECS. To ensure successful authentication, install the MongoDB client of the same version as the target instance.

    For details about how to install a MongoDB client, see How Can I Install a MongoDB Client?

  3. The ECS can communicate with the DDS instance. For details, see Configuring Security Group Rules.

SSL Connection

If you connect to an instance over the SSL connection, enable SSL first. Otherwise, an error is reported. For details about how to enable SSL, see Enabling and Disabling SSL.

  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click in the upper left corner of the page and choose Databases > Document Database Service.
  4. On the Instances page, click the instance name.
  5. In the navigation pane on the left, choose Connections.
  6. In the Basic Information area, click next to the SSL field.
  7. Upload the root certificate to the ECS to be connected to the instance.

    The following describes how to upload the certificate to a Linux and Windows ECS:

    • In Linux, run the following command:
      scp<IDENTITY_FILE><REMOTE_USER>@<REMOTE_ADDRESS>:<REMOTE_DIR>
      • IDENTITY_FILE is the directory where the root certificate resides. The file access permission is 600.
      • REMOTE_USER is the ECS OS user.
      • REMOTE_ADDRESS is the ECS address.
      • REMOTE_DIR is the directory of the ECS to which the root certificate is uploaded.
    • In Windows, upload the root certificate using a remote connection tool.

  8. Connect to a DDS instance.

    Method 1: Using the private HA connection address (recommended)

    DDS provides the HA connection address. Using this address to connect to a replica set instance improves data read/write performance and prevents errors reported when data is written from the client after a primary/standby switchover.

    Example command:

    ./mongo "<Private HA connection address>" --ssl --sslCAFile <FILE_PATH> --sslAllowInvalidHostnames

    Parameter description:

    • Private HA Connection Address: On the Instances page, click the instance name. The Basic Information page is displayed. Choose Connections. Click the Private Connection tab and obtain the connection address of the current instance from the Private HA Connection Address field.
      Figure 1 Obtaining the private HA connection address

      The format of the private HA connection address is as follows. The database username rwuser and authentication database admin cannot be changed.

      mongodb://rwuser:<password>@192.168.xx.xx:8635,192.168.xx.xx:8635/test?authSource=admin&replicaSet=replica

      Pay attention to the following parameters in the private HA address:

      Table 1 Parameter description

      Parameter

      Description

      rwuser

      Account name, that is, the database username.

      <password>

      Password for the database account. Replace it with the actual password.

      If the password contains at signs (@), exclamation marks (!), dollar signs ($), or percent signs (%), replace them with hexadecimal URL codes (ASCII) %40, %21, %24, and %25 respectively.

      For example, if the password is ****@%***!$, the corresponding URL code is ****%40%25***%21%24.

      192.168.xx.xx:8635,192.168.xx.xx:8635

      IP addresses and ports of the nodes of the replica set instance to be connected.

      test

      The name of the test database. You can set this parameter based on your service requirements.

      authSource=admin&replicaSet=replica
      • The authentication database of user rwuser must be admin. authSource=admin is fixed in the command.
      • replica in replicaSet=replica is the name of a replica set. The default replica set of Huawei Cloud DDS is replica.
    • FILE_PATH is the path for storing the root certificate.
    • --sslAllowInvalidHostnames: The replica set certificate is generated using the internal management IP address to ensure that internal communication does not occupy resources such as the user IP address and bandwidth. --sslAllowInvalidHostnames is needed for the SSL connection through a private network.

    Command example:

    ./mongo "mongodb://rwuser:<password>@192.168.xx.xx:8635,192.168.xx.xx:8635/test?authSource=admin&replicaSet=replica" --ssl --sslCAFile /tmp/ca.crt --sslAllowInvalidHostnames

    If the following information is displayed, the instance is successfully connected: 
    replica:PRIMARY>

    Run the following command to access the local database:

    use local

    Information similar to the following is displayed:

    switched to db local

    Run the following command to query replica set oplog:

    db.oplog.rs.find()

    Method 2: Using the private HA connection address (user-defined database and account)

    Example command:

    ./mongo "<Private HA connection address>" --ssl --sslCAFile <FILE_PATH> --sslAllowInvalidHostnames

    Parameter description:

    • Private HA Connection Address: On the Instances page, click the instance name. The Basic Information page is displayed. Choose Connections. Click the Private Connection tab and obtain the connection address of the current instance from the Private HA Connection Address field.
      Figure 2 Obtaining the private HA connection address

      The format of the obtained private HA connection address is as follows:

      mongodb://rwuser:<password>@192.168.xx.xx:8635,192.168.xx.xx:8635/test?authSource=admin&replicaSet=replica

      The following table lists the required parameters in the private HA address.

      Table 2 Parameter information

      Parameter

      Description

      rwuser

      Database username. The default value is rwuser. You can change the value to the username based on your service requirements.

      <password>

      Password for the database username. Replace it with the actual password.

      If the password contains at signs (@), exclamation marks (!), dollar signs ($), or percent signs (%), replace them with hexadecimal URL codes (ASCII) %40, %21, %24, and %25 respectively.

      For example, if the password is ****@%***!$, the corresponding URL code is ****%40%25***%21%24.

      192.168.xx.xx:8635,192.168.xx.xx:8635

      IP addresses and ports of the nodes of the replica set instance to be connected.

      test

      The name of the test database. You can set this parameter based on your service requirements.

      authSource=admin&replicaSet=replica
      • The authentication database of user rwuser is admin.
      • In replica in replicaSet=replica, replica indicates that the instance type is replica set and the format cannot be changed.
      NOTE:

      If you use a user-defined database for authentication, change the authentication database in the HA connection address to the name of the user-defined database. In addition, replace rwuser with the username created in the user-defined database.
    • FILE_PATH is the path for storing the root certificate.
    • --sslAllowInvalidHostnames: The replica set certificate is generated using the internal management IP address to ensure that internal communication does not occupy resources such as the user IP address and bandwidth. --sslAllowInvalidHostnames is needed for the SSL connection through a private network.

    For example, if you create a user-defined database Database and user test1 in the database, the connection command is as follows:

    ./mongo "mongodb://test1:<password>@192.168.xx.xx:8635,192.168.xx.xx:8635/Database?authSource=Database&replicaSet=replica" --ssl --sslCAFile /tmp/ca.crt --sslAllowInvalidHostnames

    Method 3: Connect to a single node.

    You can also use the private IP address of a primary or secondary node to access the replica set instance. This method affects the read/write performance when a primary/standby switchover occurs.

    Example command:

    ./mongo --host <DB_HOST> --port <DB_PORT> -u <DB_USER> -p --authenticationDatabase admin --ssl --sslCAFile<FILE_PATH> --sslAllowInvalidHostnames

    Parameter description:

    • DB_HOST is the private IP address of the primary or standby node of the instance to be connected.

      Primary node: You can read and write data on it.

      Secondary node: You can only read data from it.

      On the Instances page, click the instance to go to the Basic Information page. Choose Connections. On the Private Connection tab, obtain the IP address of the corresponding node.

      Figure 3 Obtaining the IP address of a node

    • DB_PORT is the database port. The default value is 8635.

      You can click the instance to go to the Basic Information page. In the navigation pane on the left, choose Connections. On the displayed page, click the Private Connection tab and obtain the port from the Database Port field in the Basic Information area.

      Figure 4 Obtaining the port
    • DB_USER is the database user. The default value is rwuser.
    • FILE_PATH is the path for storing the root certificate.
    • --sslAllowInvalidHostnames: The replica set certificate is generated using the internal management IP address to ensure that internal communication does not occupy resources such as the user IP address and bandwidth. --sslAllowInvalidHostnames is needed for the SSL connection through a private network.

    Enter the database account password when prompted:

    Enter password:

    Command example:

    ./mongo --host 192.168.xx.xx --port 8635 -u rwuser -p --authenticationDatabase admin --ssl --sslCAFile /tmp/ca.crt --sslAllowInvalidHostnames

    If the following information is displayed, the corresponding node is successfully connected:

    • The primary node of the replica set is connected. 
      replica:PRIMARY>
    • The standby node of the replica set is connected. 
      replica:SECONDARY>

Unencrypted Connection

If you connect to an instance over an unencrypted connection, disable SSL first. Otherwise, an error is reported. For details about how to disable SSL, see Enabling and Disabling SSL.

  1. Log in to the ECS.
  2. Connect to a DDS instance.

    Method 1: High-availability connection (recommended)

    DDS provides the HA connection address. Using this address to connect to a replica set instance improves read/write performance and prevents errors reported when data is written from the client after a primary/standby switchover.

    Example command:

    ./mongo "<Private HA Connection Address>"

    Private HA Connection Address: On the Instances page, click the instance name. The Basic Information page is displayed. Choose Connections. Click the Private Connection tab and obtain the connection address of the current instance from the Private HA Connection Address field.

    Figure 5 Obtaining the private HA connection address

    The format of the private HA connection address is as follows. The database username rwuser and authentication database admin cannot be changed.

    mongodb://rwuser:<password>@192.168.xx.xx:8635,192.168.xx.xx:8635/test?authSource=admin&replicaSet=replica

    Pay attention to the following parameters in the private HA address:

    Table 3 Parameter description

    Parameter

    Description

    rwuser

    Account name, that is, the database username.

    <password>

    Password for the database account. Replace it with the actual password.

    If the password contains at signs (@), exclamation marks (!), dollar signs ($), or percent signs (%), replace them with hexadecimal URL codes (ASCII) %40, %21, %24, and %25 respectively.

    For example, if the password is ****@%***!$, the corresponding URL code is ****%40%25***%21%24.

    192.168.xx.xx:8635,192.168.xx.xx:8635

    IP addresses and ports of the nodes of the replica set instance to be connected.

    test

    The name of the test database. You can set this parameter based on your service requirements.

    authSource=admin&replicaSet=replica
    • The authentication database of user rwuser must be admin. authSource=admin is fixed in the command.
    • replica in replicaSet=replica is the name of a replica set. The default replica set of Huawei Cloud DDS is replica.

    Command example:

    ./mongo "mongodb://rwuser:<password>@192.168.xx.xx:8635,192.168.xx.xx:8635/test?authSource=admin&replicaSet=replica"

    If the following information is displayed, the instance is successfully connected: 
    replica:PRIMARY>

    Run the following command to access the local database:

    use local

    Information similar to the following is displayed:

    switched to db local

    Run the following command to query replica set oplog:

    db.oplog.rs.find()

    Method 2: Private HA connection (user-defined database and account)

    Example command:

    ./mongo "<Private HA Connection Address>"

    Private HA Connection Address: On the Instances page, click the instance name. The Basic Information page is displayed. Choose Connections. Click the Private Connection tab and obtain the connection address of the current instance from the Private HA Connection Address field.

    Figure 6 Obtaining the private HA connection address

    The format of the obtained private HA connection address is as follows:

    mongodb://rwuser:<password>@192.168.xx.xx:8635,192.168.xx.xx:8635/test?authSource=admin&replicaSet=replica

    The following table lists the required parameters in the private HA address.

    Table 4 Parameter information

    Parameter

    Description

    rwuser

    Database username. The default value is rwuser. You can change the value to the username based on your service requirements.

    <password>

    Password for the database username. Replace it with the actual password.

    If the password contains at signs (@), exclamation marks (!), dollar signs ($), or percent signs (%), replace them with hexadecimal URL codes (ASCII) %40, %21, %24, and %25 respectively.

    For example, if the password is ****@%***!$, the corresponding URL code is ****%40%25***%21%24.

    192.168.xx.xx:8635,192.168.xx.xx:8635

    IP addresses and ports of the nodes of the replica set instance to be connected.

    test

    The name of the test database. You can set this parameter based on your service requirements.

    authSource=admin&replicaSet=replica
    • The authentication database of user rwuser is admin.
    • In replica in replicaSet=replica, replica indicates that the instance type is replica set and the format cannot be changed.
    NOTE:

    If you use a user-defined database for authentication, change the authentication database in the HA connection address to the name of the user-defined database. In addition, replace rwuser with the username created in the user-defined database.

    For example, if you create a user-defined database Database and user test1 in the database, the connection command is as follows:

    ./mongo "mongodb://test1:<password>@192.168.xx.xx:8635,192.168.xx.xx:8635/Database?authSource=Database&replicaSet=replica"

    Method 3: Connect to a single node.

    You can also use the private IP address of a primary or secondary node to access the replica set instance. This method affects the read/write performance when a primary/standby switchover occurs.

    Example command:

    ./mongo --host <DB_HOST> --port <DB_PORT> -u <DB_USER> -p --authenticationDatabase admin

    Parameter description:

    • DB_HOST is the private IP address of the primary or standby node of the instance to be connected.

      Primary node: You can read and write data on it.

      Secondary node: You can only read data from it.

      On the Instances page, click the instance to go to the Basic Information page. Choose Connections. On the Private Connection tab, obtain the IP address of the corresponding node.

      Figure 7 Obtaining the IP address of a node

    • DB_PORT is the database port. The default value is 8635.

      You can click the instance to go to the Basic Information page. In the navigation pane on the left, choose Connections. On the displayed page, click the Private Connection tab and obtain the port from the Database Port field in the Basic Information area.

      Figure 8 Obtaining the port
    • DB_USER is the database user. The default value is rwuser.

    Command example:

    ./mongo --host 192.168.xx.xx --port 8635 -u rwuser -p --authenticationDatabase admin

    Enter the database account password when prompted:

    Enter password:

    If the following information is displayed, the corresponding node is successfully connected:

    • The primary node of the replica set is connected. 
      replica:PRIMARY>
    • The standby node of the replica set is connected. 
      replica:SECONDARY>