Werk #20089: REST API: metrics association now uses a single list of host name lookup rules

Component	REST API
Title	REST API: metrics association now uses a single list of host name lookup rules
Date	Jul 6, 2026
Level	Trivial Change
Class	New Feature
Compatibility	Incompatible - Manual interaction might be required
Checkmk versions & editions	3.0.0b1 Not yet released Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT 2.4.0p32 Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

When creating, updating or reading a host via the REST API, the "OpenTelemetry data" host attribute (metrics_association) has changed its shape.

Previously the enabled configuration held a required attribute_filters object and an optional host_name_template.

It now holds a single required host_name_lookup_rules list. Each entry describes one host name lookup rule with its resource_attributes, scope_attributes, data_point_attributes and an optional host_name_template. A host has at least one rule, so the list must not be empty.

To migrate, move your attribute_filters and host_name_template into a single entry of the new list.

Before:

["enabled", {
    "attribute_filters": {
        "resource_attributes": [{"key": "service.name", "value": "shop"}],
        "scope_attributes": [],
        "data_point_attributes": []
    },
    "host_name_template": "$RESOURCE_ATTR.service.name$"
}]

After:

["enabled", {
    "host_name_lookup_rules": [
        {
            "resource_attributes": [{"key": "service.name", "value": "shop"}],
            "scope_attributes": [],
            "data_point_attributes": [],
            "host_name_template": "$RESOURCE_ATTR.service.name$"
        }
    ]
}]

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