Database Configuration¶

This guide covers MongoDB installation and configuration for CraneSched.

Info

MongoDB is only required on the control node. Compute nodes do not need MongoDB.

1. Install MongoDB¶

Install MongoDB Community Edition¶

Please follow the official MongoDB installation guide for your operating system:

MongoDB Community Edition Installation Guide

CentOS 7 Users

CentOS 7 has reached End of Life (EOL) and the latest MongoDB version it supports is MongoDB 7.0.

Please refer to the MongoDB 7.0 installation guide for Red Hat/CentOS 7.

Example: Rocky Linux 9¶

For Rocky Linux 9, the installation process typically involves:

# Create repository file (check MongoDB docs for the latest version)
cat > /etc/yum.repos.d/mongodb-org.repo << 'EOF'
[mongodb-org-8.2]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/9/mongodb-org/8.2/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://pgp.mongodb.com/server-8.0.asc
EOF

dnf makecache
dnf install -y mongodb-org
systemctl enable mongod
systemctl start mongod

Example: Ubuntu/Debian¶

For Ubuntu/Debian systems:

# Follow the official guide for the latest instructions
# Typical steps include importing GPG key and adding repository
curl -fsSL https://www.mongodb.org/static/pgp/server-8.0.asc | \
   sudo gpg -o /usr/share/keyrings/mongodb-server-8.0.gpg \
   --dearmor

echo "deb [ signed-by=/usr/share/keyrings/mongodb-server-8.0.gpg ] http://repo.mongodb.org/apt/debian bookworm/mongodb-org/8.2 main" | sudo tee /etc/apt/sources.list.d/mongodb-org-8.2.list

# Add repository and install
sudo apt-get update
sudo apt-get install -y mongodb-org
sudo systemctl enable mongod
sudo systemctl start mongod

Tip

The examples above may become outdated. Always refer to the official MongoDB documentation for the most current installation instructions.

2. Configure MongoDB¶

2.1 Generate Key File¶

Create a key file for replica set authentication:

openssl rand -base64 756 | sudo -u mongod tee /var/lib/mongo/mongo.key
sudo -u mongod chmod 400 /var/lib/mongo/mongo.key

2.2 Create Admin User¶

Connect to MongoDB and create an admin user:

mongosh
use admin
db.createUser({
    user: 'admin', 
    pwd: '123456',  # Change this in production!
    roles: [{ role: 'root', db: 'admin' }]
})
db.shutdownServer()
quit

Warning

Use a strong password for the admin user in production environments.

2.3 Enable Authentication and Replication¶

Edit /etc/mongod.conf:

security:
  authorization: enabled
  keyFile: /var/lib/mongo/mongo.key
replication:
  replSetName: crane_rs

Restart MongoDB:

systemctl restart mongod

2.4 Initialize Replica Set¶

mongosh
use admin
db.auth("admin","123456")
config = {
  "_id": "crane_rs",
  "members": [
    {
      "_id": 0,
      "host": "<hostname>:27017"  # Replace with your control node hostname
    }
    # Add more members here if you have multiple MongoDB nodes
  ]
}
rs.initiate(config)
quit

3. Configure CraneSched Database Connection¶

Create /etc/crane/database.yaml on the control node only:

DbUser: admin
DbPassword: "123456"
DbHost: localhost
DbPort: 27017
DbReplSetName: crane_rs
DbName: crane_db

Warning

This file should only exist on the control node and be readable only by root or the crane user:

chmod 600 /etc/crane/database.yaml

Troubleshooting¶

Connection failed: Ensure MongoDB is running and the firewall allows port 27017.

Authentication failed: Verify the username and password in database.yaml match the MongoDB user.

Replica set errors: Check that the replSetName in mongod.conf matches the value in database.yaml.