Storage & Volumes

Containers are ephemeral by default—data is lost when the container restarts. Use volumes and mounts to persist data across deployments.

Overview

Senate supports multiple storage types:

Docker Services

For Docker services, configure storage in the Storage tab.

Adding a Mount

1. Navigate to your service
2. Go to the Storage tab
3. Click Add Mount
4. Configure the mount:

Volume Mount

Docker-managed named volumes:

# Creates a volume named "myapp-data" mounted at /app/data
Type: volume
Source: myapp-data  
Destination: /app/data

Bind Mount

Mount a host directory into the container:

# Mounts host directory /host/data to container /app/data
Type: bind
Source: /host/data
Destination: /app/data

File Mount

Inject a single file into the container:

# Creates /app/config.json with specified content
Type: file
Destination: /app/config.json
Content: {"debug": false, "port": 3000}

Use cases:

• Configuration files
• SSL certificates
• Custom scripts
• Nginx configs

Compose Services

For Compose services, storage is defined in your docker-compose.yml:

services:
  app:
    volumes:
      - app-data:/app/data          # Named volume
      - ./config:/app/config:ro     # Bind mount (read-only)
      
volumes:
  app-data:

The Storage tab shows current mounts in read-only mode for Compose services.

Viewing Container Mounts

The Storage tab displays:

1. Configured Mounts: Mounts defined in Senate (Docker services)
2. Runtime Mounts: Actual mounts on running containers

For each mount:

• Type (volume, bind, file)
• Source location
• Destination path
• Read/write mode

Volume Management

Disk Usage

View volume disk usage in the Storage tab. Shows:

• Total size
• Used space
• Available space

Volume Location

Volumes are stored on the host at:

/var/lib/docker/volumes/{volume-name}/_data

Best Practices

Database Storage

Always use volumes for databases:

# PostgreSQL
Source: postgres-data
Destination: /var/lib/postgresql/data

# MySQL
Source: mysql-data
Destination: /var/lib/mysql

# MongoDB
Source: mongo-data
Destination: /data/db

File Uploads

For user-uploaded files:

Source: uploads
Destination: /app/uploads

Backups

Implement a backup strategy:

1. Use volume snapshots (if supported by host)
2. Run backup containers with volume access
3. Copy to external storage (S3, etc.)

Read-Only Mounts

Use read-only mounts for:

• Configuration files
• Static assets
• Shared libraries

Source: config-files
Destination: /app/config
Read Only: true

Related

• PostgreSQL Cookbook - Database setup
• Redis Cookbook - Cache storage
• Services - Service configuration