Connecting to a Replica Set Instance Using Mongo Shell (Private Network)

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

The following describes how to upload the certificate to a Linux and Window 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.

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 you connect to an instance over a private HA address, add double quotation marks before and after the connection information.
• For details about the HA connection, see Connecting to a Replica Set Instance for Read and Write Separation and High Availability.

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>

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:

Command example:

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

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.

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>