MongoDB - Simplify migration to Galaxy Database

Step-by-step guide for using a Docker image to migrate MongoDB databases to Galaxy Databases, including creating a new user post-migration for improved security and access control.

Prerequisites

Before using this Docker image, make sure you have the following:

• Docker installed on your machine.
• Source and target MongoDB URIs ready and tested.
• IP whitelist configured on MongoDB Atlas if applicable.

Step-by-Step Guide

Get the MongoDB URIs

1. Obtain the source MongoDB URI in the format: mongodb+srv://<username>:<password>@<source-cluster>
2. Get the MongoDB target URI from the Galaxy Database team in the format: mongodb://<username>:<password>@<destination-host>:<port>

Run the Docker Container

Use the following command to run the migration container:

docker run --rm \
  -e SOURCE_URI="" \
  -e TARGET_URI="" \
  -e DB_NAME="example_source_db_name" \
  meteor/galaxy-mongodb-migrate:202506181938

Replace SOURCE_URI, TARGET_URI, and DB_NAME with your actual values.

Example

docker run --rm \
  -e SOURCE_URI="mongodb+srv://username:password@source-cluster.mongodb.net" \
  -e TARGET_URI="mongodb://username:password@destination-host-01.mongodb.net:27017,destination-host-02.mongodb.net:27017,destination-host-03.mongodb.net:27017/admin?replicaSet=replicaSetName" \
  -e DB_NAME="example_source_db_name" \
  meteor/galaxy-mongodb-migrate:202506181938

Creating User for the Database

We recommend creating a new user specifically for the database after migration to enhance security and access control.

Recommended Steps

1. Database Migration: Execute the database migration ensuring all data is successfully transferred to the new environment.

2. Connect to the Destination Database: Use our compass guide on connecting to MongoDB.

3. Select the Database: Select the migrated database (e.g., use example_db_name).

4. Create the New User: Create a new user specific to this database. For example:

db.createUser({
  user: "newuser",
  pwd: "<new-secure-password>",
  roles: ["readWrite"]
})

Replace <new-secure-password> with the password for the new user.

5. Verify the New User: Ensure the new user has been successfully created:

db.getUsers()

Now you can use a URI like this in your Meteor app:

mongodb://newuser:pass@destination-host-01.mongodb.net:27017,destination-host-02.mongodb.net:27017,destination-host-03.mongodb.net:27017/example_db_name?replicaSet=NameOfYourReplicaSet&readPreference=secondary

Security Considerations

• Use secure passwords for your users.
• Assign only necessary permissions.
• Regularly review user privileges.

Troubleshooting

• Check connection details and permissions.
• Review logs for errors.

Users

To effectively manage your MongoDB cluster, the Galaxy Database team sets up several MongoDB users within your clusters:

• admin@admin: Initial user with administrative privileges.
• galaxyadmin@admin: Technical user required for automation.
• galaxybackup@admin: User designated for performing backups.
• galaxymonitor@admin: User used for monitoring.

Please do not delete these users.

Creating a MongoDB user for Oplog

To set up an oplog user, configure a MongoDB replica set:

1. Connect to your database using our compass guide.

2. Open your console and run:

db.createUser({
  user: "oplogger",
  pwd: "PasswordForOplogger",
  roles: [{ role: "read", db: "local" }]
})

The oplog user must be created in the admin database with read permissions to the local database.

3. Your new MongoDB connection string will be:

mongodb://oplogger:PasswordForOplogger@mongo-1.example.com,mongo-2.example.com,mongo-3.example.com/local?authSource=admin&replicaSet=replicaSetName

Ensure authSource=admin is included at the end.

Support

For migrations without downtime, contact our team at support@meteor.com.

This documentation provides a comprehensive guide for using Docker to migrate MongoDB databases to Galaxy Databases, along with best practices for creating and managing users post-migration.

Updated on: 18/06/2025