NSO live-status: how to use this great, undocumented feature properly

[rslaski]

Hi developers,

For the new project, I'll have to deviate from NSO orchestration functions a little bit - the requirement is not only to deploy services, but also validate their operation. And yes, we could use any external custom-built system for that, but why duplicate things, while most of the required data is inside the NSO. That's how I found a feature called 'live-status', which triggers NED 'stats' module to retrieve some operational data (and of course, many f-words were spoken here, trying to find just anything in the documentation).

So my basic questions are:

1) How to trigger live-status from Python code?

I've found one quite good explanation in the forum, so let's consider that as explained a little:

https://community.cisco.com/t5/nso-developer-hub-discussions/how-do-i-call-the-devices-device-foo-config-exec-action-from/td-p/3750061

2) How to trigger live-status from API?

I probably should use POST over some never documented URI, something like:

http://{{NSO_IP}}:{{NSO_HTTP_PORT}}/restconf/data/tailf-ncs:devices/device=NX_LEAF111/live-status/tailf-ned-cisco-nx-stats:exec/any

However what should be put inside the body is still unknown to me, so I get:

"error-message": "External error in the NED implementation for device NX_LEAF111: missing argument(s) for subcmd=any",

3) Can we augment the NED stats tree with own fields, populated with values read from device with my own callback code?

thanks,
robert

[Jason Belk]

Hi!

Yes, the exec live status is a wonderful feature that is often not talked about enough. 

I don't have a RESTCONF example handy, though I have a Python one:

https://github.com/NSO-developer/nso-5-day-training/blob/master/nso_python_api_examples.py#L134

Also if you are looking for other restconf examples, I made this postman collection:

https://github.com/NSO-developer/cisco-nso-postman

(though I admit it does not have the live status, I plan to add it soon)

[lmanor · Accepted solution]

For question #2 from RESTCONF:

The exec/any command is an action that is defined in the XE (and other) NED:

From XE NED yang:

container exec {

    tailf:info "Execute commands on device";

{…}

    // any [arg 1] .. [arg N]

    tailf:action any {

      tailf:info "Execute any command on device";

      tailf:actionpoint ncsinternal {

        tailf:internal;

      }

      input {

        leaf-list args {

          tailf:cli-drop-node-name;

          tailf:cli-flat-list-syntax;

          type string {

            tailf:info "WORD;;any <cmd> [option(s)], e.g: any event manager run my_applet (see README for more info)";

          }

        }

      }

      output {

        leaf result {

          type string;

        }

      }

    }

So you need to provide the 'input' to the action - here is a RESTCONF example from IOS-XR, XE should be same:

curl -i -u admin:admin  http://localhost:8080/restconf/operations/devices/device=xr-0/live-status/tailf-ned-cisco-ios-xr-stats:exec/any -X POST -H 'Accept: application/yang-data+json' -H 'Content-Type: application/yang-data+json' -T show-run-vrf.json

cat show-run-vrf.json

{

  "input":

  {

    "args": "show run vrf foo"

  }

}