azlin snapshot create¶

Create a point-in-time snapshot of a VM's OS disk for backup and recovery.

Description¶

The azlin snapshot create command captures the complete state of a VM's OS disk, creating a backup that can be restored later. Snapshots are incremental and cost-effective, storing only the changes since the previous snapshot.

Use snapshots for: - Backup before updates: Snapshot before major system changes - Safe experimentation: Try risky operations with easy rollback - Version control for VMs: Save different VM configurations - Disaster recovery: Quick recovery from system failures

Snapshots are named automatically with timestamps: {vm-name}-snapshot-{timestamp}

Usage¶

azlin snapshot create VM_NAME [OPTIONS]

Arguments¶

VM_NAME - Name of the VM to snapshot (required)

Options¶

Option	Description
`--resource-group, --rg TEXT`	Azure resource group
`--config PATH`	Config file path
`-h, --help`	Show help message

Examples¶

Create Basic Snapshot¶

# Create snapshot of VM
azlin snapshot create my-dev-vm

Output:

Creating snapshot of 'my-dev-vm'...
  VM Status: Running
  Disk Size: 30 GB
  Creating snapshot...

Snapshot created successfully!
  Name: my-dev-vm-snapshot-20251124-143022
  Size: 30 GB
  Location: eastus
  Cost: ~$0.06/day

Restore with:
  azlin snapshot restore my-dev-vm my-dev-vm-snapshot-20251124-143022

Snapshot with Specific Resource Group¶

azlin snapshot create prod-server --rg azlin-prod-rg

Snapshot Before Risky Operation¶

# 1. Create safety snapshot
azlin snapshot create my-vm

# 2. Perform risky operation
azlin connect my-vm
sudo rm -rf /var/log/*  # Dangerous operation

# 3. If something breaks, restore:
#    azlin snapshot restore my-vm my-vm-snapshot-20251124-143022

Scheduled Snapshots (via cron)¶

# Create daily snapshot script
cat > ~/snapshot-daily.sh << 'EOF'
#!/bin/bash
azlin snapshot create production-vm
# Keep only last 7 snapshots
azlin snapshot list production-vm | tail -n +8 | awk '{print $1}' | xargs -I {} azlin snapshot delete {} --force
EOF

chmod +x ~/snapshot-daily.sh

# Add to crontab (daily at 2 AM)
crontab -e
# 0 2 * * * ~/snapshot-daily.sh

Snapshot Multiple VMs¶

# Snapshot all VMs in resource group
for vm in $(azlin list --format names); do
    echo "Snapshotting $vm..."
    azlin snapshot create $vm
done

Common Use Cases¶

Pre-Update Backup¶

# Before system updates
azlin snapshot create my-vm

# Perform updates
azlin connect my-vm
sudo apt update && sudo apt upgrade -y
exit

# Test everything works
# If issues: azlin snapshot restore my-vm {snapshot-name}

Development Checkpoints¶

# Save working state before major changes
azlin snapshot create dev-vm  # Working state

# Make changes to codebase
# ...test...

# If broken, restore working state
azlin snapshot restore dev-vm dev-vm-snapshot-20251124-120000

Experiment Safely¶

# 1. Create snapshot
azlin snapshot create experiment-vm

# 2. Try experimental changes
azlin connect experiment-vm
# Install beta software, change configs, etc.

# 3. If experiment fails
azlin snapshot restore experiment-vm {snapshot-name}

# 4. If experiment succeeds
# Keep the VM, delete old snapshot
azlin snapshot delete {snapshot-name}

Compliance and Audit¶

# Weekly compliance snapshots
azlin snapshot create compliance-server

# Tag for audit trail
# Snapshots automatically include timestamp
# Keep for required retention period

Pre-Deployment Checkpoint¶

# Before deploying new version
azlin snapshot create production-api

# Deploy new version
azlin connect production-api
cd /opt/app && git pull && systemctl restart app

# Monitor for issues
# If problems: quick rollback
#   azlin snapshot restore production-api {snapshot-name}

Snapshot Naming Convention¶

Snapshots are automatically named:

{vm-name}-snapshot-{YYYYMMDD}-{HHMMSS}

Examples: - my-dev-vm-snapshot-20251124-143022 - production-api-snapshot-20251124-020000 - gpu-trainer-snapshot-20251123-235959

The timestamp ensures: - Unique names (no conflicts) - Chronological sorting - Easy identification of snapshot age

VM State During Snapshot¶

VM can remain running during snapshot creation: - No downtime required - Snapshot captures disk state at start of operation - Safe for production VMs - Takes 1-5 minutes typically

Best practice: For critical systems, create snapshots during low-traffic periods for consistency.

Snapshot Size and Cost¶

Size¶

First snapshot: Full disk size (30-1024 GB)
Subsequent snapshots: Only changes (incremental)
Compressed and deduplicated by Azure

Example progression:

Day 1: 30 GB disk → 30 GB snapshot
Day 2: 2 GB changes → 2 GB snapshot
Day 3: 1 GB changes → 1 GB snapshot
Total: 33 GB stored

Cost¶

Standard snapshots: ~$0.05/GB/month ($0.002/GB/day)
Premium snapshots: ~$0.12/GB/month ($0.004/GB/day)

Example costs: | Disk Size | Monthly Cost | Daily Cost | |-----------|--------------|------------| | 30 GB | $1.50 | $0.05 | | 128 GB | $6.40 | $0.21 | | 512 GB | $25.60 | $0.85 | | 1 TB | $51.20 | $1.71 |

Tip: Delete old snapshots to reduce costs. Keep only what you need for recovery.

Troubleshooting¶

Snapshot Creation Failed¶

Error: "Failed to create snapshot: Operation timed out"

Solution: Check VM and disk status:

# Check VM status
azlin list --vm my-vm

# Verify VM is accessible
azlin connect my-vm --command "echo 'VM is up'"

# Retry snapshot
azlin snapshot create my-vm

Insufficient Permissions¶

Error: "Insufficient permissions to create snapshot"

Solution: Ensure you have Contributor role:

# Test authentication
azlin auth test

# Re-authenticate if needed
az login

Quota Exceeded¶

Error: "Snapshot quota exceeded"

Solution: Delete old snapshots:

# List all snapshots
azlin snapshot list my-vm

# Delete old ones
azlin snapshot delete my-vm-snapshot-20251001-120000

VM Not Found¶

Error: "VM 'xyz' not found"

Solution: Check VM name and resource group:

# List VMs
azlin list

# Use correct name
azlin snapshot create correct-vm-name

Best Practices¶

Snapshot Retention Policy¶

Implement a retention strategy:

# Example: Keep 7 daily, 4 weekly, 3 monthly

# Daily snapshots (keep 7)
azlin snapshot create my-vm
# Delete snapshots older than 7 days

# Weekly snapshots (keep 4) - run on Sundays
# Delete snapshots older than 28 days

# Monthly snapshots (keep 3) - run on 1st
# Delete snapshots older than 90 days

Snapshot Before Changes¶

Always snapshot before: - Operating system updates - Application deployments - Configuration changes - Database migrations - Security patches - Experimental installations

Test Restores¶

Periodically test snapshot restores:

# 1. Clone VM for testing
azlin clone my-vm --name restore-test

# 2. Create snapshot of test VM
azlin snapshot create restore-test

# 3. Restore from snapshot
azlin snapshot restore restore-test {snapshot-name}

# 4. Verify restore works
azlin connect restore-test

# 5. Clean up test VM
azlin destroy restore-test

Document Snapshots¶

Keep notes on what each snapshot represents:

# Create snapshot with descriptive naming
# (use VM tags or external documentation)
azlin snapshot create my-vm  # Creates: my-vm-snapshot-20251124-143022
# Note: "Pre-Python 3.13 upgrade"

Performance Considerations¶

Snapshot Creation Time¶

Small disks (< 64 GB): 1-3 minutes
Medium disks (64-256 GB): 3-5 minutes
Large disks (256-1024 GB): 5-15 minutes

Impact on VM Performance¶

Minimal impact during snapshot
Slight I/O slowdown (< 5%)
No downtime required
Safe for production systems

Parallel Snapshots¶

You can snapshot multiple VMs simultaneously:

# Snapshot all VMs in parallel
azlin list --format names | xargs -P 5 -I {} azlin snapshot create {}

azlin snapshot list - List all snapshots for a VM
azlin snapshot restore - Restore VM from snapshot
azlin snapshot delete - Delete old snapshots
azlin clone - Clone VM (includes snapshot)