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Topology: Entities & Relationships

Hands-on2 exercises

What is Topology?

Topology turns your metrics into entities — things you can click on in Dynatrace. A device entity, interface entities, sensor entities — each with their own page.

Without topology, you just have metrics floating in space. With topology, you get a device page showing "Switch-01" with its interfaces listed below.

Entity Types

Define entity types in the topology: section:

topology:
  types:
    - name: my_ext:device
      displayName: My Device
      enabled: true
      rules:
        - idPattern: my_ext_device_{device.address}
          instanceNamePattern: "{sys.name} ({device.address})"
          sources:
            - sourceType: Metrics
              condition: $prefix(com.dynatrace.extension.my-ext)
          requiredDimensions:
            - key: device.address
          role: default

Key Fields Explained

Field	Purpose	Example
`name`	Entity type ID (prefix:type)	`my_ext:device`
`idPattern`	Globally unique entity ID	`my_ext_device_{device.address}`
`instanceNamePattern`	Display name in UI	`{sys.name} ({device.address})`
`condition`	Links metrics to this entity type	`$prefix(com.dynatrace.extension.my-ext)`
`requiredDimensions`	Dimensions that must exist	`device.address`
`role`	`default` = parent entity	Only on the top-level device

idPattern must be globally unique — always include device.address plus a child identifier. Two devices with the same idPattern merge into one entity.

🛠 Try it

Add a child entity type topo_lab:interface below the device type. Use {device.address}_{if.name} in the idPattern to make it unique. No role: needed for children.

extension.yamlYAML

Relationships

Connect child entities to parents with CHILD_OF:

  relationships:
    - fromType: my_ext:interface
      toType: my_ext:device
      typeOfRelation: CHILD_OF
      enabled: true
      sources:
        - sourceType: Metrics
          condition: $prefix(com.dynatrace.extension.my-ext)

This makes interfaces appear as children on the device detail page.

Entity Attributes

Show extra info on entity pages with attributes::

attributes:
  - key: dt.ip_addresses        # special: enables IP lookup
    pattern: "{device.address}"
  - key: devDescription
    displayName: Description
    pattern: "{sys.descr}"

💡 Special attribute keys: dt.ip_addresses enables IP lookup, dt.listen_ports shows ports, dt.dns_names shows DNS names.

Common Entity Type Patterns

Entity Type	Role	ID Pattern Includes
`ext:device`	`default` (parent)	`device.address`
`ext:interface`	child	`device.address` + `if.name`
`ext:power_supply`	child	`device.address` + `psu.idx`
`ext:sensor`	child	`device.address` + `sensor.idx`

🛠 Try itExercise 2

Add a CHILD_OF relationship from topo_lab:interface to topo_lab:device.

extension.yamlYAML

What's Next

Module 6 — Screens & Dashboards. Build the UI pages that display your entity data.

← PreviousAdvanced SNMPNext →Screens & Dashboards