MongoDB Deployment Checklist

When transitioning from a development environment to production, deploying a MongoDB database requires careful planning and consideration. This guide provides a comprehensive checklist to ensure your MongoDB deployment is secure, performant, and reliable.

Introduction

MongoDB is a powerful NoSQL database that offers flexibility and scalability for modern applications. However, a successful MongoDB deployment requires more than just installing the software and running it. This checklist covers essential aspects you should consider before deploying MongoDB in a production environment.

Whether you're deploying a single MongoDB instance, a replica set, or a sharded cluster, this guide will help you avoid common pitfalls and implement best practices from the start.

Pre-Deployment Planning

1. Hardware Requirements Assessment

Before deploying MongoDB, ensure your hardware meets the minimum requirements:

Memory Considerations

MongoDB uses memory-mapped files for data storage. Ideally, your server should have enough RAM to hold:

• The working set (frequently accessed data)
• Indexes
• Connection overhead

Example calculation:

javascript

// Calculate approximate RAM requirements
const documentsCount = 10000000; // 10 million documents
const avgDocumentSize = 2000; // bytes
const indexOverhead = 0.1; // 10% of data size
const connectionOverhead = 1024 * 1024 * 1000; // 1000 MB for connections

const totalDataSize = documentsCount * avgDocumentSize;
const totalIndexSize = totalDataSize * indexOverhead;
const recommendedRAM = (totalDataSize + totalIndexSize + connectionOverhead) / (1024 * 1024 * 1024);

console.log(`Recommended RAM: ${recommendedRAM.toFixed(2)} GB`);
// Output: Recommended RAM: 19.58 GB

2. Deployment Architecture Decision

Based on your application needs, decide on the appropriate MongoDB deployment architecture:

1. Standalone - Single MongoDB instance (Not recommended for production)
2. Replica Set - Multiple MongoDB instances with automatic failover
3. Sharded Cluster - Horizontally scaled MongoDB deployment for high throughput and large data volumes

For most production workloads, a replica set with at least three nodes is recommended:

javascript

// Sample replica set initialization
rs.initiate({
  _id: "myReplicaSet",
  members: [
    { _id: 0, host: "mongodb-0.example.com:27017" },
    { _id: 1, host: "mongodb-1.example.com:27017" },
    { _id: 2, host: "mongodb-2.example.com:27017" }
  ]
});

Security Configuration

3. Authentication and Authorization

Always enable authentication in production environments:

javascript

// Create admin user
use admin
db.createUser({
  user: "adminUser",
  pwd: "securePassword123",  // Use a strong password
  roles: [{ role: "userAdminAnyDatabase", db: "admin" }]
})

// Create application user with restricted access
use myApp
db.createUser({
  user: "appUser",
  pwd: "anotherSecurePassword456",
  roles: [{ role: "readWrite", db: "myApp" }]
})

Update your mongod.conf to enable authentication:

yaml

security:
  authorization: enabled

4. Network Security

Secure your MongoDB deployment at the network level:

1. IP Binding: Bind MongoDB to specific IP addresses, not 0.0.0.0
2. Firewall Rules: Set up firewall rules to restrict access to MongoDB ports
3. TLS/SSL: Enable TLS/SSL for encrypted connections

yaml

# mongod.conf
net:
  bindIp: 10.0.0.4,127.0.0.1  # Bind to specific IPs
  port: 27017
  ssl:
    mode: requireSSL
    PEMKeyFile: /path/to/mongodb.pem

5. MongoDB Configuration File

Create a properly configured mongod.conf file:

yaml

# Basic mongod.conf for a replica set member
systemLog:
  destination: file
  path: "/var/log/mongodb/mongod.log"
  logAppend: true

storage:
  dbPath: "/var/lib/mongodb"
  journal:
    enabled: true
  wiredTiger:
    engineConfig:
      cacheSizeGB: 2  # Adjust based on available RAM

net:
  bindIp: 127.0.0.1,192.168.1.100
  port: 27017
  
security:
  authorization: enabled
  
replication:
  replSetName: "myReplicaSet"

processManagement:
  timeZoneInfo: /usr/share/zoneinfo

Performance Optimization

6. Storage Engine Configuration

MongoDB uses the WiredTiger storage engine by default. Optimize it based on your workload:

yaml

storage:
  dbPath: "/var/lib/mongodb"
  journal:
    enabled: true
  wiredTiger:
    engineConfig:
      cacheSizeGB: 4  # Set to ~60% of available RAM
      journalCompressor: snappy  # Options: none, snappy, zlib
    collectionConfig:
      blockCompressor: snappy
    indexConfig:
      prefixCompression: true

7. Index Planning

Plan your indexes carefully based on your query patterns. Missing indexes can severely impact performance:

javascript

// Create indexes for frequently queried fields
db.users.createIndex({ email: 1 }, { unique: true });
db.orders.createIndex({ user_id: 1, order_date: -1 });
db.products.createIndex({ 
  name: "text", 
  description: "text" 
}, { 
  weights: { 
    name: 10, 
    description: 5 
  },
  name: "product_search_index"
});

// Check index usage for query optimization
db.orders.find({ user_id: "12345" }).explain("executionStats");

Remember to analyze your index usage regularly:

javascript

// Find unused indexes
db.collection.aggregate([
  { $indexStats: {} },
  { $match: { "accesses.ops": { $lt: 1 } } }
])

Backup and Recovery Strategy

8. Backup Implementation

Set up regular backups using MongoDB's native tools:

bash

# Full backup using mongodump
mongodump --uri="mongodb://username:password@host:port/dbname" \
  --out=/backup/mongodb/$(date +"%Y-%m-%d")

# Using mongodump with compression
mongodump --uri="mongodb://username:password@host:port/dbname" \
  --gzip --out=/backup/mongodb/$(date +"%Y-%m-%d")

For larger deployments, consider filesystem snapshots or MongoDB Cloud Manager.

9. Backup Verification and Recovery Testing

Regularly test your backups by restoring them to a test environment:

bash

# Restore from backup
mongorestore --uri="mongodb://username:password@host:port/" \
  --gzip /backup/mongodb/2023-08-01

Write a script to verify the restored data:

javascript

// Verification script example
const collections = db.getCollectionNames();
const verificationResults = {};

collections.forEach(collection => {
  const count = db[collection].countDocuments();
  const sampleDoc = db[collection].findOne();
  
  verificationResults[collection] = {
    documentCount: count,
    hasData: sampleDoc !== null,
    sampleDocId: sampleDoc ? sampleDoc._id : null
  };
});

printjson(verificationResults);

Monitoring and Alerting

10. Monitoring Setup

Set up comprehensive monitoring for your MongoDB deployment:

1. Use MongoDB's built-in tools: db.serverStatus(), db.stats()
2. Set up MongoDB Cloud Manager or MongoDB Ops Manager
3. Integrate with monitoring platforms like Prometheus/Grafana, Datadog, or New Relic

Example of a basic MongoDB health check script:

javascript

// health-check.js
const mongoClient = require('mongodb').MongoClient;

async function checkMongoDB() {
  try {
    const client = await mongoClient.connect('mongodb://username:password@host:port/admin');
    
    // Check server status
    const serverStatus = await client.db('admin').command({ serverStatus: 1 });
    
    // Extract key metrics
    const metrics = {
      connections: serverStatus.connections.current,
      activeClients: serverStatus.globalLock.activeClients,
      opcounters: serverStatus.opcounters,
      memory: {
        resident: serverStatus.mem.resident,
        virtual: serverStatus.mem.virtual
      }
    };
    
    console.log('MongoDB health check passed:', metrics);
    client.close();
    return true;
  } catch (error) {
    console.error('MongoDB health check failed:', error);
    return false;
  }
}

checkMongoDB();

11. Alert Configuration

Configure alerts for critical MongoDB metrics:

• High connection count
• Lock percentage
• Replication lag
• Query performance
• Disk space usage
• Missing indexes (queries without index usage)

Example Prometheus alerting rule for MongoDB:

yaml

groups:
- name: mongodb_alerts
  rules:
  - alert: MongoDBHighConnections
    expr: mongodb_connections{state="current"} > 5000
    for: 5m
    labels:
      severity: warning
    annotations:
      summary: "MongoDB high connections (instance {{ $labels.instance }})"
      description: "MongoDB connections are high (> 5000) for more than 5 minutes"

  - alert: MongoDBReplicationLag
    expr: mongodb_replset_member_optime_date{state="SECONDARY"} - ON (set, service) mongodb_replset_member_optime_date{state="PRIMARY"} > 60
    for: 2m
    labels:
      severity: critical
    annotations:
      summary: "MongoDB replication lag (instance {{ $labels.instance }})"
      description: "Replication lag is more than 60 seconds"

Scaling and Maintenance

12. Scaling Strategy

Plan your scaling strategy based on your application's growth:

1. Vertical Scaling: Adding more resources (RAM, CPU, faster disks)
2. Horizontal Scaling: Adding more nodes through sharding

When implementing sharding:

javascript

// Enable sharding for a database
sh.enableSharding("myDatabase")

// Create a hashed shard key for even distribution
db.runCommand({
  shardCollection: "myDatabase.users",
  key: { userId: "hashed" }
})

// Create a ranged shard key for location-based data
db.runCommand({
  shardCollection: "myDatabase.stores",
  key: { location: 1 }
})

13. Regular Maintenance Tasks

Schedule regular maintenance tasks:

javascript

// Compact collections during off-peak hours
db.runCommand({ compact: "users" })

// Update indexes in the background
db.products.reIndex()

// Monitor and kill long-running operations
db.currentOp({ "secs_running": { $gt: 300 } })

Create a maintenance script that can be scheduled:

javascript

// maintenance.js
const performMaintenance = async (db) => {
  console.log("Starting database maintenance...");
  
  // Get database stats
  const stats = await db.stats();
  console.log(`Database size: ${stats.dataSize / 1024 / 1024} MB`);
  
  // Find collections that might need attention
  const collections = await db.listCollections().toArray();
  
  for (const collection of collections) {
    const collName = collection.name;
    const collStats = await db.collection(collName).stats();
    
    // Check if indexes need rebuilding (high ratio)
    if (collStats.nindexes > 0 && collStats.totalIndexSize > 500 * 1024 * 1024) {
      console.log(`Large index size for ${collName}: ${collStats.totalIndexSize / 1024 / 1024} MB`);
    }
    
    // Check for collections with many deleted documents
    if (collStats.count > 10000 && collStats.wiredTiger) {
      const docsDeleted = collStats.wiredTiger.creationTime;
      if (docsDeleted / collStats.count > 0.3) {
        console.log(`Collection ${collName} has high delete ratio, consider compaction`);
      }
    }
  }
  
  console.log("Maintenance check completed");
};

Deployment Checklist Summary

Here's a consolidated checklist to ensure a successful MongoDB deployment:

1. Hardware Planning

   • Provision sufficient RAM for working set
   • Use SSDs for data storage
   • Configure RAID for disk redundancy (if applicable)

2. Architecture

   • Implement a replica set with at least 3 nodes
   • Configure proper write concern for your use case
   • Plan for sharding if needed

3. Security

   • Enable authentication and authorization
   • Configure TLS/SSL for encrypted connections
   • Implement network isolation and firewall rules
   • Use strong passwords and role-based access control

4. Configuration

   • Create a proper mongod.conf file
   • Optimize WiredTiger cache size
   • Configure appropriate journaling settings
   • Set proper log rotation

5. Performance

   • Create proper indexes based on query patterns
   • Configure appropriate read/write concerns
   • Set up connection pooling in application

6. Backup & Recovery

   • Implement regular backup schedule
   • Test backup restoration process
   • Document recovery procedures
   • Store backups in multiple locations

7. Monitoring

   • Set up proactive monitoring
   • Configure alerts for critical metrics
   • Implement a log analysis solution

8. Maintenance

   • Schedule regular maintenance windows
   • Plan for version upgrades
   • Document operational procedures

Conclusion

Deploying MongoDB in a production environment requires careful planning and attention to detail. By following this checklist, you can ensure your MongoDB deployment is secure, performant, and ready for production use. Remember that database deployment is not a one-time activity but an ongoing process that requires regular monitoring and maintenance.

As your application grows, you may need to revisit your deployment architecture and make adjustments to accommodate increased load and data volume. Regularly review your MongoDB deployment to ensure it continues to meet your application's needs.

Additional Resources

• MongoDB Production Notes (Official Documentation)
• MongoDB University - Free MongoDB Training Courses
• MongoDB Security Checklist

Exercises

1. Create a testing environment with a MongoDB replica set using Docker or virtual machines.
2. Set up monitoring for your test MongoDB deployment using Prometheus and Grafana.
3. Develop and test a backup and restore strategy for your MongoDB database.
4. Practice upgrading a MongoDB deployment from one minor version to the next.
5. Create a load testing scenario and identify performance bottlenecks in your MongoDB deployment.

By completing these exercises, you'll gain practical experience with MongoDB deployment and be better prepared to manage MongoDB in production environments.