PyUtrecht (NL) meetup: streaming telemetry (network monitoring with gRPC and gNMI) - Maurice Stoof¶

Tags: python, pun

(One of my summaries of the PyUtrecht meetup in Utrecht, NL).

“From SNMP to gRPC”. Maurice is working on network automation. (The link goes to his github account, the presentation’s demo code is there).

SNMP, the Simple Network Monitoring Protocol, has been the standard for network monitoring since 1980. But its age is showing. It is polling-pased, which is wasteful. The mechanism will continually poll the endpoints. It is like checking for new messages on your phone every minute instead of relying on push messaging.

The better way is streaming telemetry, the push model. He uses gRPC, “A high performance, open source universal RPC framework” and gNMI, “gRPC Network Management Interface”.

You can ask for capabilities: used in the discovery phase. Get is a simple one-time request for a specific value. With set you can do a bit of configuring. The magic is in subscribe: it creates a persistent connection, allowing the device to continuously stream data back to the client (according to the settings done with “set”).

(For the demo, he use pyGMNI, a handy python library for gNMI.)

When to use streaming?

• With high-frequency monitoring. If you need data more frequent than once every 10 seconds.

• When you need real-time alerting.

• Large-scale deployments. With lots of devices, polling efficiency starts to pay off.

SNMP is still fine when you have small setup and hign frequency isn’t really needed.