compose-anything/src/mongodb-replicaset-single

MongoDB Single-Node Replica Set

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This service sets up a single-node MongoDB replica set, ideal for development and testing environments.

Prerequisites

1. Generate a key file for the replica set:

   openssl rand -base64 756 > ./secrets/rs0.key
   

   On Windows, you can use Git Bash or WSL, or download the key file from the MongoDB documentation.

Initialization

1. Start the services:

   docker compose up -d
   

   The services will automatically initialize the replica set through the mongo-init init container. This container:

   • Waits for the MongoDB node to be healthy
   • Connects to the node
   • Initializes the single-node replica set
   • Uses container-based networking for communication

2. Verify the replica set status:

   docker exec -it mongodb-replicaset-single-mongo1-1 mongosh -u root -p password --authenticationDatabase admin --eval "rs.status()"
   

Services

• mongo1: The only member of the replica set.

Configuration

• TZ: The timezone for the container, default is UTC.
• MONGO_VERSION: The version of the MongoDB image, default is 8.0.13.
• MONGO_INITDB_ROOT_USERNAME: The root username for the database, default is root.
• MONGO_INITDB_ROOT_PASSWORD: The root password for the database, default is password.
• MONGO_INITDB_DATABASE: The initial database to create, default is admin.
• MONGO_REPLICA_SET_NAME: The name of the replica set, default is rs0.
• MONGO_PORT_OVERRIDE_1: The host port for the MongoDB node, default is 27017.
• MONGO_HOST: The host name for the MongoDB node, default is mongo1.

Volumes

• mongo_data: A named volume for MongoDB data persistence.
• secrets/rs0.key: The key file for authenticating members of the replica set.

Security

The replica set key file is mounted read-only and copied to /tmp inside the container with proper permissions (400). This approach ensures cross-platform compatibility (Windows/Linux/macOS) while maintaining security requirements. The key file is never modified on the host system.

Using the Single-Node Replica Set

You can connect to the MongoDB replica set using any MongoDB client:

mongosh "mongodb://root:password@localhost:27017/admin?authSource=admin&replicaSet=rs0"

Or using Python with PyMongo:

from pymongo import MongoClient

client = MongoClient("mongodb://root:password@localhost:27017/admin?authSource=admin&replicaSet=rs0")
db = client.admin
print(db.command("ping"))