ON THIS PAGE
IBA Monitoring of Devices in Drain Mode
A prebuilt IBA (intent-based analytics) probe is available in Juniper Apstra. You can activate it by instantiating a predefined probe named “Drain traffic anomaly”. The required value for Threshold in bps works as follows:
- Value is the net sum of traffic on all hosted_interfaces
- This does not include traffic on the Ethernet management port which is not part of the probe measurement
- These interfaces include all L3 BGP enabled paths
- Server facing interfaces are shut during Drain Mode and are not part of this calculation
- The threshold describes the amount of traffic you wish to be alerted on (above the value) if devices are in the Drain state
- This ensures that you do not perform actual maintenance operations on a device that has not been fully drained.
Example
Spine1 is connected to 4 leaf switches, each connection runs the eBGP routing process. All application (server) based traffic flows are rehashed via ECMP onto other links and the basic BGP neighbor updates are still running. In a lab example with a small topology, this is effectively 1.5KBPS per link. With 4 neighbors, the total traffic we expect to remain on the devices is approximately 6KBPS. If we set the probe Threshold in bps to 10KBPS (10000), the probe generates anomalies if there is more than 10K on all of the 4 interfaces combined.
Recommended Usage
Enable the probe with 100KBPS and leave it running in all Blueprints. When a device enters the Drain state, an anomaly appears as the traffic is removed from the links. This anomaly should only exist for a few seconds. If the anomaly does not clear, the device is not fully in Drain Mode. Once the anomaly clears, you are free to switch the device to the Ready state to take it out of service completely. It is also possible that you will not see the anomaly as it may appear and disappear very quickly.