Tags

Tags are organization-wide labels you apply to hosts, services, subnets, networks, groups, and daemons. They're defined once for the organization, shared by every user, and usable across all networks — deleting one removes it from every entity that carried it.

There are two kinds, and they behave differently.

Standard tags

Free-form labels. An entity can carry as many as you like, and they're used for filtering — in entity lists, and in the topology, where filtered elements fade rather than disappear so the layout stays stable.

Common schemes:

• Environment — production, staging, development
• Criticality — critical, high, medium, low
• Ownership — which team runs it
• Lifecycle — deprecated, migrating, new
• Compliance — pci-scope, hipaa, gdpr, internal-only

Combining two axes is usually more useful than one long list. production + critical identifies core infrastructure in a way that neither tag does alone.

Application tags

An application tag answers "what is this part of?" rather than "what is this like", so the rules are stricter:

• A host or service carries at most one.
• A service inherits its host's application tag. A host tagged billing lends that to every service on it, without tagging each one.
• Tagging a service directly overrides what it inherited. Use this for the service on a shared host that belongs to something else.

This inheritance is what the Application perspective groups on — each application tag becomes a container, and services fall into it by their own tag or their host's. A host running one thing needs a single tag; only the exceptions need tagging individually.

Managing tags

Tags live under Platform > Tags, and can also be created inline while editing any entity. Renaming one updates it everywhere it's applied.