Filtering Empty Values
SNMP devices often return n/a or empty strings for unused interfaces. Filter them out to prevent ghost entities:
dimensions:
- key: if.name
value: oid:1.3.6.1.2.1.31.1.1.1.1
filter: const:$not($eq(n/a))
💡 Without this filter, Dynatrace creates entity pages for empty interfaces nobody cares about.
32-bit vs 64-bit Counters
32-bit counters wrap at ~4GB. On a 10Gbps link, that's every 3.4 seconds — making the data useless. Always use 64-bit:
| Metric | 32-bit (avoid) | 64-bit (use) |
|---|---|---|
| Bytes In | 1.3.6.1.2.1.2.2.1.10 ifInOctets | 1.3.6.1.2.1.31.1.1.1.6 ifHCInOctets |
| Bytes Out | 1.3.6.1.2.1.2.2.1.16 ifOutOctets | 1.3.6.1.2.1.31.1.1.1.10 ifHCOutOctets |
| Unicast In | 1.3.6.1.2.1.2.2.1.11 ifInUcastPkts | 1.3.6.1.2.1.31.1.1.1.7 ifHCInUcastPkts |
| Unicast Out | 1.3.6.1.2.1.2.2.1.17 ifOutUcastPkts | 1.3.6.1.2.1.31.1.1.1.11 ifHCOutUcastPkts |
⚠️ The 32-bit OIDs are from IF-MIB (ifTable). The 64-bit OIDs are from IF-MIB (ifXTable). Both share the same ifIndex — safe to mix in one subgroup.
Replace the 32-bit counter OIDs with their 64-bit equivalents. ifInOctets → ifHCInOctets (1.3.6.1.2.1.31.1.1.1.6), ifOutOctets → ifHCOutOctets (1.3.6.1.2.1.31.1.1.1.10).
Cross-Table Mixing (DED018)
Each SNMP table has its own index space. You cannot mix OIDs from different tables in the same subgroup:
| Table | Index | Example OIDs |
|---|---|---|
| ifTable / ifXTable | ifIndex | ifDescr, ifHCInOctets, ifHighSpeed |
| ipAddrTable | ipAdEntAddr | ipAdEntIfIndex, ipAdEntNetMask |
| entPhysicalTable | entPhysicalIndex | entPhysicalDescr, entPhysicalClass |
⚠️ Mixing ifTable OIDs with ipAddrTable OIDs in one subgroup = wrong data matched to wrong rows. This was the exact bug in ACI v0.0.3.
Compatible exceptions (shared index): ifTable + ifXTable, entPhysicalTable + entSensorValueTable.
OID Validation Rules (from Dynatrace source)
These are the exact validation checks Dynatrace runs on your OIDs:
Check DED Code Rule
─────────────────────── ──────── ──────────────────────────────────────
OID syntax DED015 Must match /^\d[.\d]+\d$/ — no leading/trailing dots
OID in bundled MIBs DED010 OID must exist in a MIB file in snmp/ directory
Scalar vs table DED016 table:true → OID must NOT end in .0
table:false → OID MUST end in .0
Cross-table OIDs DED018 All OIDs in a subgroup must share same table index
Metric key naming DED006 Count metrics must have .count suffix
Metric key naming DED007 Gauge metrics must NOT have .count suffix
Duplicate metric keys DED001 Each metric key must be unique
Missing dimensions DED003 Table metrics need at least one dimension
💡 Run python3 validate_extension.py ext/ to check all these rules before building. DED018 (cross-table) is the #1 bug found across 13 real extension validations.
Extensions API v2 — Lifecycle
The full extension lifecycle via API (18 endpoints):
1. Upload: POST /api/v2/extensions (multipart, zip file)
2. List: GET /api/v2/extensions (all extensions)
3. Get: GET /api/v2/extensions/{name} (versions list)
4. Activate: POST /api/v2/extensions/{name}/{version}/environmentConfiguration
5. Configure: POST /api/v2/extensions/{name}/monitoringConfigurations
6. Status: GET /api/v2/extensions/{name}/{version}/environmentConfiguration
7. Delete: DELETE /api/v2/extensions/{name}/{version}
This subgroup mixes ifTable and ipAddrTable OIDs — a DED018 cross-table bug. Move the IP address OID (1.3.6.1.2.1.4.20.1.1) into its own subgroup called IP Addresses.
What's Next
Module 5 — Topology. Turn your metrics into entities that appear in the Dynatrace UI with relationships.