About machine groups

Distinguish groups of machines by assigning availability zones, tags, and resource pools.

Availability zones

An availability zone is an organizational unit containing nodes, with each node belonging to exactly one zone. Zones help with fault tolerance, service performance, and power management. Machines can be allocated from specific zones in production.

Fault tolerance

Fault tolerance ensures a system continues operating despite failures. MAAS zones can improve resilience by separating resources based on power supply, network segmentation, or data center location.

  • Machines working together should be in the same zone.
  • The entire service should be replicated in another zone for redundancy.

Service performance

Service performance focuses on efficiency and speed. MAAS zones help by placing nodes close to performance-critical resources.

  • Allocate nodes based on network topology and latency needs.
  • Use smaller, well-defined zones to group resources efficiently.

Power management

Power management optimizes power usage and cooling.

  • Distribute high-power or heat-generating nodes across zones.
  • Prevent hotspots and balance power consumption.

Default zone

A newly installed MAAS includes a default zone that holds all nodes. You cannot remove or rename this zone, but you can create new ones and assign machines. If zones aren’t relevant to your setup, you can ignore them.

Tags

As your infrastructure scales, tags simplify navigation and management. Tags are short, descriptive, searchable words that can be applied to various MAAS objects, including:

  • machines (physical and virtual)
  • VM hosts
  • controllers (rack and region)
  • storage (virtual and physical; block devices or partitions)
  • network interfaces
  • devices
  • nodes (in the CLI only)

Tags serve to help you identify, group, and find objects easily, especially when you routinely deploy hundreds of machines.

Key attributes

  • Tags & annotations: Identify machines and influence behavior.
  • Filtering: UI-based machine search.

Learn about usage: Tags | Annotations | Search

Tag anatomy

  • Tags: Short descriptors for machines, VM hosts, controllers, storage, and network interfaces.
  • Annotations: Detailed, static or dynamic descriptions.
  • Scripts: Tags can group scripts for commissioning/testing.

Automatic tags

Automatic tagging is available in MAAS v3.2+.

Define machine criteria via XPath expressions. Tags apply automatically based on:

  • Hardware features (mapped from lshw XML output).
  • Node capabilities (CPU, network speed, etc.).
  • Kernel options, combined alphabetically at boot.

Annotations

Annotations are descriptive, searchable phrases that apply only to machines. There are two types of annotations: notes (always present in any machine state), and dynamic (only present in allocated or deployed states). Annotations help you identify, characterize, and inform others about your machines.

Resource pools

Resource pools in MAAS let admins group machines and VM hosts logically, aiding in resource allocation for specific functions. By default, all machines are added to the “default” pool, but custom pools can be created for specific needs. For example, in a hospital data center, you might reserve machines for applications like charts, documentation, or orders.

Assigning machines to resource pools ensures they’re allocated appropriately, regardless of the specific application deployed on them. This grouping also enhances multi-tenancy by restricting user access based on roles and assigned pools. MAAS auto-assigns new machines to the “default” resource pool.

Last updated 2 days ago.

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