topic Re: hostname remains same for devices under common list in NSO Developer Hub Discussions

hostname remains same for devices under common list

amardkum — Fri, 27 Sep 2019 07:52:52 GMT

Hi Team,

I am trying to provision multiple devices under common list and I am observing that the value against HOSTNAME is having first device name for all others in the list.

Below is the sample yang and template file:

cat yang/HOSTNAME.yang

module HOSTNAME {

namespace "http://com/example/HOSTNAME";

prefix HOSTNAME;

import ietf-inet-types {

prefix inet;

}

import tailf-ncs {

prefix ncs;

}

list HOSTNAME {

key NAME;

uses ncs:service-data;

ncs:servicepoint "HOSTNAME";

leaf NAME {

type string;

}

leaf-list DEVICE {

type leafref {

path "/ncs:devices/ncs:device/ncs:name";

}

cat ../templates/HOSTNAME-template.xml

<config-template xmlns="http://tail-f.com/ns/config/1.0" servicepoint="HOSTNAME">

<device><name>{/DEVICE}</name>

<hostname xmlns="http://tail-f.com/ned/cisco-ios-xr">{string(/DEVICE)}</hostname>

</config>

</device>

</devices>

</config-template>

Upon using this service and selecting two devices from same list, I see below configs:

SJC-DEV1

hostname SJC-DEV1

PHX-DEV1

hostname SJC-DEV1

Please suggest if I am missing anything.

Thanks,

Amar

Re: hostname remains same for devices under common list

rogaglia — Mon, 30 Sep 2019 18:29:05 GMT

well...you missing an iterator. Something like this (not tested but check the developer guide):

<config-template xmlns="http://tail-f.com/ns/config/1.0" servicepoint="HOSTNAME">

<hostname xmlns="http://tail-f.com/ned/cisco-ios-xr">{string(.)}</hostname>

</config>

</device>

</devices>

</config-template>

Re: hostname remains same for devices under common list

amardkum — Mon, 30 Sep 2019 19:15:48 GMT

Thank you @rogaglia . It worked as suggested.

Re: hostname remains same for devices under common list

lmanor — Mon, 30 Sep 2019 20:34:44 GMT

The problem is that the /device in the hostname config is setting back to the first entry in the device leaf-list.

When the device leaf-list is hit it will iterate through each of the devices in the list, and set the context to that device. In this case you want to use device to set the hostname. Since your context is at device, then you'll want to set you hostname to {.} :

A good way to see what in going on with the template engine processing is to use 'debug template'..

admin@ncs% commit dry-run | debug template

Evaluating "/device" (from file "hostname-template.xml", line 5)

Context node: /hostname[name='nh1']

Result:

For /hostname[name='nh1']/device[.='iosxr-0'], it evaluates to "iosxr-0"

For /hostname[name='nh1']/device[.='iosxr-1'], it evaluates to "iosxr-1"

Operation 'merge' on existing node: /devices/device[name='iosxr-0'] (from file "hostname-template.xml", line 5)

Operation 'merge' on existing node: /devices/device[name='iosxr-0']/config/cisco-ios-xr:hostname (from file "hostname-template.xml", line 7)

Evaluating "." (from file "hostname-template.xml", line 7)

Context node: /hostname[name='nh1']/device[.='iosxr-0']

Result:

For /hostname[name='nh1']/device[.='iosxr-0'], it evaluates to "iosxr-0"

Setting /devices/device[name='iosxr-0']/config/cisco-ios-xr:hostname to "iosxr-0"

Operation 'merge' on existing node: /devices/device[name='iosxr-1'] (from file "hostname-template.xml", line 5)

Operation 'merge' on non-existing node: /devices/device[name='iosxr-1']/config/cisco-ios-xr:hostname (from file "hostname-template.xml", line 7)

Evaluating "." (from file "hostname-template.xml", line 7)

Context node: /hostname[name='nh1']/device[.='iosxr-1']

Result:

For /hostname[name='nh1']/device[.='iosxr-1'], it evaluates to "iosxr-1"

Setting /devices/device[name='iosxr-1']/config/cisco-ios-xr:hostname to "iosxr-1"

cli {

local-node {

data devices {

device iosxr-0 {

config {

- cisco-ios-xr:hostname test1;

+ cisco-ios-xr:hostname iosxr-0;

}

device iosxr-1 {

config {

+ cisco-ios-xr:hostname iosxr-1;

}

+hostname nh1 {

+ device [ iosxr-0 iosxr-1 ];

}

Re: hostname remains same for devices under common list

amardkum — Wed, 02 Oct 2019 16:21:45 GMT

Thank you @lmanor for your response and suggestion. The "debug template" option would be a help for sure.

I also came across "commit dry-run | debug template and commit | debug xpath and commit | debug service" option to get more info.

In my case, I do not have a leaf-list but a container that has list and in this case, I had to use the KEY used under that list to get the current device.

// ---------------- INTERNET_FACING_WAN_ROUTER List --------------------------------
        container INTERNET_FACING_WAN_ROUTERS {
            tailf:info "Internet facing WAN Device Specific Config";
            list INTERNET_FACING_WAN_ROUTER {
                key "INTERNET_FACING_WAN_ROUTER";
                leaf INTERNET_FACING_WAN_ROUTER {
                    type leafref {
                        path "/ncs:devices/ncs:device/ncs:name";
                    }
                }
                uses SNMP_SERVER_SPECIFIC_PARAMETERS;
                uses TACACS_SPECIFIC_PARAMETERS;
                uses SYSLOG_SPECIFIC_PARAMETERS;
                uses NTP_SPECIFIC_PARAMETERS;
            }
        } //container INTERNET_FACING_WAN_ROUTERS