VM Selectors¶

Advanced techniques for selecting VMs in batch operations.

Selection Methods¶

1. By Tag¶

Most flexible - use Azure tags:

azlin batch command 'uptime' --tag env=dev
azlin batch stop --tag project=ml-training

Best for: Logical groupings (environment, project, team)

2. By Pattern¶

Glob patterns for VM names:

azlin batch command 'df -h' --vm-pattern 'web-*'
azlin batch start --vm-pattern '*-worker'
azlin batch stop --vm-pattern 'test-vm-[0-9]'

Best for: Naming conventions and numbered fleets

3. All VMs¶

Select everything in resource group:

azlin batch command 'uptime' --all --confirm

Best for: Fleet-wide operations

Pattern Syntax¶

* - Matches any characters
? - Matches single character
[0-9] - Matches digits
[a-z] - Matches lowercase letters

Examples¶

# All web servers
--vm-pattern 'web-*'

# Numbered workers (worker-1, worker-2, ...)
--vm-pattern 'worker-*'

# Test VMs only
--vm-pattern 'test-*'

# Specific range
--vm-pattern 'vm-[1-5]'

Combining with Resource Groups¶

# Dev environment VMs in specific RG
azlin batch command 'uptime' --tag env=dev --rg dev-team

# Production web servers
azlin batch command 'systemctl status nginx' \
  --vm-pattern 'web-*' \
  --rg production

Best Practices¶

Use tags for logical groups: Environment, project, role
Use patterns for numbered fleets: web-1, web-2, etc.
Test selection first: Use azlin list --tag env=dev to verify
Combine methods: Can't use --tag and --vm-pattern together, choose one