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Version: 2024.1

Configure MongoDB in HA Mode (Cluster)

Using MongoDB in high availability mode requires the use of MongoDB replica sets. A replica set is a group of mongod processes that manage the same data set, providing redundancy and high availability. For additional information, see the official MongoDB documentation: https://docs.mongodb.com/manual/replication/.

To configure the MongoDB cluster:

  1. Install MongoDB on all the nodes in your cluster.

  2. Stop the MongoDB Server Service (if running).

  3. Run Command Prompt as administrator, navigate to the MongoDB Server's \bin directory (usually at C:\Program Files\MongoDB\Server\4.2\bin\) and run this command:

    mongod --dbpath "C:\Program Files\MongoDB\Server\4.2\data" --logpath "C:\Program Files\MongoDB\Server\4.2\log\mongod.log" --port 27017 --replSet rsTest -–bind_ip 0.0.0.0

    or for multiple nodes:

    mongod --dbpath "C:\Program Files\MongoDB\Server\4.2\data" --logpath "C:\Program Files\MongoDB\Server\4.2\log\mongod.log" --port 27017 --replSet rsTest -–bind_ip localhost, <IP1>, <IP2>, <IP3>…
    Notes:
    • You can change all variables in the command and also run the command through a config file.
    • Make sure you set --bind_ip to 0.0.0.0 or include the IPs of the machines that need to access the MongoDB, including the other machines in the cluster. For details, see this MongoDB docs article: https://docs.mongodb.com/manual/core/security-mongodb-configuration/.

  4. Repeat steps 2 and 3 for each node in the cluster.

  5. In one of the nodes, connect to the Mongo shell from a different Command-Prompt and run the following command:

    rs.initiate( {
       _id : "rsTest",
       members: [
          { _id: 0, host: "<1st_node_ip>:27017" },
          { _id: 1, host: "<2nd_node_ip>:27017" },
          { _id: 2, host: "<3rd_node_ip>:27017" }
       ]
    })

    Note: Host addresses must be either all IPs or all hostnames.

  6. To verify the state of the replica set and set configurations, run:

    rs.status()

  7. On each secondary node, connect to the mongo shell from a different Command-Prompt and run the following command:

    • On MongoDB 4.2:

      rs.slaveOk()

    • On MondoDB 4.4 and up:

      rs.secondaryOk()

  8. Later on in the High Availability installation process, you will also need to install a MongoDB cluster as part of the Quali Server installation and specify the cluster's connection strings. This is all explained in Select the Database Type and Configure the MongoDB Database Connection.