The NETCONF Agent has the following guideline and limitation:

• Cisco NX-OS supports both the Cisco Device YANG model and OpenConfig models in NETCONF notifications.

• The device YANG model defines ephemeral data and they are marked with a comment "// Ephemeral data". These nonpersistent large-volume data is handled differently from the rest of the model. They are returned only when <get> query's <filter> parameter points specifically to the particular element marked with the comment. Refer to the ephemeral data support documentation for detailed information on the usage.

• Beginning with Cisco NX-OS Release 9.3(3), NETCONF is RFC 6241 compliant with the following exceptions:

  • Sibling content match nodes are logically combined in an "OR" expression instead of an "AND" expression. (Section 6.2.5)

  • Once a candidate datastore has been edited, the running configuration for the same property must not be edited.

• In a single Get request, the number of objects that are supported is 250,000. If you see the following error, it means that the data requested is more than 250,000. To avoid this error, send requests with filters querying for a narrower scope of data.

  too many objects(459134 > 250000) to query the entire device model.

• NETCONF does not support enhanced Role-Based Access Control (RBAC) as specified in RFC 6536. Only users with a "network-admin" role are granted access to the NETCONF agent.

• The <edit-config> "replace" operation sometimes might not work due to run-time default values and behaviors that are implemented by the affected system component. Therefore, it's better to base the configuration to replace on the configuration obtained through the <get-config> query instead of the NX-API Developer Sandbox.

• The Cisco NX-OS NETCONF server supports a maximum of five subscriptions, one subscription per client session.

• Per RFC 5277, autonomous notifications support NETCONF, SYSLOG, and SNMP streams for event sources. In this release, Cisco NX-OS supports NETCONF streams only.

• Cisco NX-OS does not support the Replay option for subscriptions. Because Start Time and Stop Time options are part of Replay, they are not supported.

• For a stream subscription and filtering, support is only for subtree filtering. XPath filtering is not supported.

• When the Cisco NX-OS NETCONF Agent is operating under a heavy load, it is possible that some event notifications can get dropped.

• You cannot configure NETCONF on a switch if NAT is already configured. The configurations of NETCONF and NAT are incompatible and cannot coexist on the same switch.

• Cisco NX-OS supports both the Cisco Device YANG model and OpenConfig models. Support for OpenConfig models in NETCONF notifications begins with the Cisco NX-OS 9.3(5) release.

• Beginning with 10.2(1)F release, the operations checkpoint, rollback, install, import ca certificate, module reload, individual module reload, and copy file are supported.

• When openconfig-acl NETCONF GET operations are performed with L2 MAC leaf property value(s) as input, it is recommended to input the letters in MAC addresses in the uppercase format (AA:AA: AA:AA:AA:AA). For example, source-mac: 0A:0B:0C:0D:0E:0F.

NETCONF is a connection-oriented protocol requiring a persistent connection between client and server. The NETCONF agent on the switch listens at port 830 of the management port IP address. The client can establish a connection with the NETCONF subsystem over SSH. When a client establishes a session with the NETCONF agent, the server sends a <hello> message to the client. The client likewise must send its <hello> message to the server. The <hello> messages are exchanged simultaneously as soon as the connection is open. Each <hello> message contains a list of the sending peer’s protocol version and capabilities. These messages are used to determine protocol compatibility and capabilities. Both NETCONF peers must verify that a common protocol version is advertised by the other peer’s <hello> message. Also, the server’s <hello> message must include a <session-id> whereas the client’s <hello> message must not.

The following shows an example session establishment using the ssh command. The first <hello> message is received from the server and the second message is sent from the client. The server’s <hello> message shows the protocol version “urn:ietf:params:netconf:base:1.1” and NETCONF base capabilities that are supported on Cisco NX-OS Release 9.3(4). Also, the server’s <hello> message includes supported data models. They might not match the models supported in the current Cisco NX-OS release.

Note	The server’s <hello> message has a <session-id>, but the client’s message does not.

client-host % ssh admin@172.19.193.166 -p 830 -s netconf
User Access Verification
Password: 
<?xml version="1.0" encoding="UTF-8"?>
<hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
    <capabilities>
        <capability>urn:ietf:params:netconf:base:1.0</capability>
        <capability>urn:ietf:params:netconf:base:1.1</capability>
        <capability>urn:ietf:params:netconf:capability:writable-running:1.0</capability>
        <capability>urn:ietf:params:netconf:capability:rollback-on-error:1.0</capability>
        <capability>urn:ietf:params:netconf:capability:candidate:1.0</capability>
        <capability>urn:ietf:params:netconf:capability:validate:1.1</capability>
        <capability>urn:ietf:params:netconf:capability:confirmed-commit:1.1</capability>
        <capability>urn:ietf:params:netconf:capability:notification:1.0</capability>
        <capability>urn:ietf:params:netconf:capability:interleave:1.0</capability>
        <capability>urn:ietf:params:netconf:capability:with-defaults:1.0?basic-mode=report-all</capability>
        <capability>http://cisco.com/ns/yang/cisco-nx-os-device?revision=2020-04-20&amp;module=Cisco-NX-OS-device</capability>
        <capability>http://openconfig.net/yang/acl?revision=2019-11-27&amp;module=openconfig-acl&amp;deviations=cisco-nx-openconfig-acl-deviations</capability>
        <capability>http://openconfig.net/yang/bfd?revision=2019-10-25&amp;module=openconfig-bfd&amp;deviations=cisco-nx-openconfig-bfd-deviations</capability>
        ...
    </capabilities>
    <session-id>1286775422</session-id>
</hello>
]]>]]><hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <capabilities>
    <capability>urn:ietf:params:netconf:base:1.1</capability>
  </capabilities>
</hello>
]]>]]>

Using NETCONF with the ssh command is not convenient and is prone to error, as the complexity for message framing can be seen from RFC 6242 (Using the NETCONF Protocol over SSH). The ssh command is used for the example above for illustration purposes only. There are various clients written for NETCONF which are recommended over the ssh command. The ncclient is one such example and is used in the Usage Examples section.

NETCONF supports two operations for terminating a session, namely, <close-session> and <kill-session>. When the server receives a <close-session> request, it gracefully terminates the session by releasing any locks and resources associated with the session and closing the connection with the client. The following is an example of the <close-session> request and response for success:

<rpc message-id="1" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <close-session/>
</rpc>
 
<rpc-reply message-id="1" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <ok/>
</rpc-reply>

The <kill-session> request forces the termination of another session and requires <session-id> in the request message. Upon receiving the <kill-session> request, the server terminates current operations, releases locks and resources, and closes the connection associated with the specified session ID. The following is an example of the <kill-session> request and response for success:

<rpc message-id="2" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <kill-session>
    <session-id>296324181</session-id>
  </kill-session>
</rpc>
 
<rpc-reply message-id="2" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <ok/>
</rpc-reply>

Besides the <close-session> and <kill-session> requests, a session is terminated automatically if the client does send any request for a certain length of time. The default is five minutes. See Configuring the NETCONF Agent for configuring the idle timeout.

This section describes supported base protocol operations to manipulate and query datastores. The client can send RPC messages for these operations after establishing a session with the NETCONF agent. Basic usage explanations are given and RFC 6242 can be referred to for thorough details about these operations.

<get-config>

This operation retrieves configuration data from a specified datastore. The supported parameters are <source> and <filter>. The <source> specifies the datastore being queried such as <running/>, which holds the currently active configuration. The <filter> specifies the portions of the specified datastore to retrieve.

The following are examples of <get-config> request and response messages.

• Retrieve the entire <System> subtree:

  <rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <get-config>
          <source>
              <running/>
          </source>
          <filter>
              <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device"/>
          </filter>
      </get-config>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="101">
      <data>
          <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
          ...
          </System>
      </data>
  </rpc-reply>
  
  

• Retrieve a specific list item:

  <rpc message-id="102" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <get-config>
          <source>
              <running/>
          </source>
          <filter>
              <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
                  <bgp-items>
                      <inst-items>
                          <dom-items>
                              <Dom-list>
                                  <name>default</name>
                              </Dom-list>
                          </dom-items>
                      </inst-items>
                  </bgp-items>
              </System>
          </filter>
      </get-config>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="102">
      <data>
          <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
              <bgp-items>
                  <inst-items>
                      <dom-items>
                          <Dom-list>
                              <name>default</name>
                              ...
                              <rtctrl-items>
                                  <enforceFirstAs>enabled</enforceFirstAs>
                                  <fibAccelerate>disabled</fibAccelerate>
                                  <logNeighborChanges>enabled</logNeighborChanges>
                                  <supprRt>enabled</supprRt>
                              </rtctrl-items>
                              <rtrId>1.2.3.4</rtrId>
                          </Dom-list>
                      </dom-items>
                  </inst-items>
              </bgp-items>
          </System>
      </data>
  </rpc-reply>
  
  

<edit-config>

This operation writes a specified configuration to the target datastore. The <target> parameter specifies the datastore being edited, such as <running/> or <candidate/>. The candidate datastore can be manipulated without impacting the running datastore until its changes are committed. For more information, see the <commit> section. The <config> parameter specifies the modeled data to be written to the target datastore. The model is specified by the “xmlns” attribute. Any number of elements in the <config> subtree may contain an “operation” attribute. The operation of an element is inherited by its descendent elements until it’s overridden by a new “operation” attribute. The supported operations are “merge”, “replace”, “create”, “delete”, and “remove”. The “remove” operation is different from “delete” in that no error is returned if the configuration data does not exist. If the “operation” attribute is not specified, the merge operation is assumed as default; the default operation can be overridden by the optional <default-operation> parameter, which has “merge”, “replace” or “none”.

The following are examples of <edit-config> request and response messages.

• Create a port-channel named "po5" with MTU 9216 and the description in the running configuration:

  <rpc message-id="103" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <edit-config>
          <target>
              <running/>
          </target>
          <config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
              <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
                  <intf-items>
                      <aggr-items>
                          <AggrIf-list xc:operation="create">
                              <id>po5</id>
                              <mtu>9216</mtu>
                              <descr>port-channel 5</descr>
                          </AggrIf-list>
                      </aggr-items>
                  </intf-items>
              </System>
          </config>
      </edit-config>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="103">
      <ok/>
  </rpc-reply>
  
  

• Replace all configurations of a port-channel with new configurations:

  <rpc message-id="104" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <edit-config>
          <target>
              <running/>
          </target>
          <config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
              <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
                 <intf-items>
                      <aggr-items>
                          <AggrIf-list xc:operation="replace">
                              <id>po5</id>
                              <mtu>1500</mtu>
                              <adminSt>down</adminSt>
                          </AggrIf-list>
                      </aggr-items>
                  </intf-items>
              </System>
          </config>
      </edit-config>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="104">
      <ok/>
  </rpc-reply>

• Delete a port-channel:

  <rpc message-id="105" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <edit-config>
          <target>
              <running/>
          </target>
          <config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
             <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
                  <intf-items>
                      <aggr-items>
                          <AggrIf-list xc:operation="delete">
                              <id>po5</id>
                          </AggrIf-list>
                      </aggr-items>
                  </intf-items>
              </System>
          </config>
      </edit-config>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="105">
      <ok/>
  </rpc-reply>
  
  

<copy-config>

This operation replaces the target configuration datastore with the contents of source configuration datastore. The parameters for source datastore and target datastore are <source> and <target>, respectively.

The following are examples of <copy-config> request and response messages.

• Copy from running configuration to startup configuration:

  <rpc message-id="106" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <copy-config>
          <target>
              <startup/>
          </target>
          <source>
              <running/>
          </source>
      </copy-config>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="106">
      <ok/>
  </rpc-reply>
  
  

• Copy from running configuration to candidate configuration:

  <rpc message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <copy-config>
          <target>
              <candidate/>
          </target>
          <source>
              <running/>
          </source>
      </copy-config>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="107">
      <ok/>
  </rpc-reply>
  
  

<lock>

The <lock> operation allows a client to lock the configuration datastore, preventing other clients from locking or modifying the datastore. The lock that is held by the client is released with either the <unlock> operation or termination of a session. The <target> parameter is used to specify the datastore to be locked.

The following are examples of <lock> request and response messages.

• A successful acquisition of a lock:

  <rpc message-id="108" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <lock>
          <target>
              <running/>
          </target>
      </lock>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="108">
      <ok/>
  </rpc-reply>
  
  

• A failed attempt to acquire a lock already in use by another session:

  <rpc message-id="109" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <lock>
          <target>
              <candidate/>
          </target>
      </lock>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="109">
      <rpc-error>
          <error-type>protocol</error-type>
          <error-tag>lock-denied</error-tag>
          <error-severity>error</error-severity>
          <error-message xml:lang="en">Lock failed, lock is already held</error-message>
          <error-info>
              <session-id>1553704357</session-id>
          </error-info>
      </rpc-error>
  </rpc-reply>
  
  

<unlock>

The <unlock> operation releases a configuration lock, obtained with the <lock> operation. Only the same session that issued the <lock> operation can use the <unlock> operation. The <target> parameter is used to specify the datastore to be unlocked.

The following is an example of <unlock> request and response messages.

• Unlock

  <rpc message-id="110" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <unlock>
          <target>
              <candidate/>
          </target>
      </unlock>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="110">
      <ok/>
  </rpc-reply>
  
  

<get>

The <get> operation retrieves running configuration and operational state data. The supported parameter is <filter>. The <filter> specifies the portions of the running configuration operational state data to retrieve.

The following is an example of <get> request and response messages.

• Retrieve running configuration and operational state data of a list item:

  <rpc message-id="111" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <get>
          <filter>
              <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
                  <bgp-items>
                      <inst-items>
                          <dom-items>
                              <Dom-list>
                                  <name>default</name>
                              </Dom-list>
                          </dom-items>
                      </inst-items>
                  </bgp-items>
              </System>
          </filter>
      </get>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="111">
      <data>
          <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
              <bgp-items>
                  <inst-items>
                      <dom-items>
                          <Dom-list>
                              <name>default</name>
                              <always>disabled</always>
                              <bestPathIntvl>300</bestPathIntvl>
                              <clusterId>120</clusterId>
                              <firstPeerUpTs>2020-04-20T16:19:03.784+00:00</firstPeerUpTs>
                              <holdIntvl>180</holdIntvl>
                              <id>1</id>
                              <kaIntvl>60</kaIntvl>
                              <mode>fabric</mode>
                              <numEstPeers>0</numEstPeers>
                              <numPeers>0</numPeers>
                              <numPeersPending>0</numPeersPending>
                              <operRtrId>1.2.3.4</operRtrId>
                              <operSt>up</operSt>
                              <pfxPeerTimeout>90</pfxPeerTimeout>
                              <pfxPeerWaitTime>90</pfxPeerWaitTime>
                              <reConnIntvl>60</reConnIntvl>
                              <rtrId>1.2.3.4</rtrId>
                              <vnid>0</vnid>
                              ...
                          </Dom-list>
                      </dom-items>
                  </inst-items>
              </bgp-items>
          </System>
      </data>
  </rpc-reply>
  
  

<validate>

This operation validates the configuration contents of the candidate datastore. It is useful for validating the configuration changes made on the candidate datastore before committing them to the running datastore. The <source> parameter supports <candidate/>.

The following is an example of <validate> request and response messages.

• Validate the contents of the candidate datastore:

  <rpc message-id="112" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <validate>
          <source>
              <candidate/>
          </source>
      </validate>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="112">
      <ok/>
  </rpc-reply>
  
  

<commit>

This operation commits the candidate configuration to the running configuration. The operation without any parameter is considered final and cannot be reverted. If <commit> is issued with the <confirmed/> parameter, it is considered a confirmed commit, and commit is finalized only if it is followed by another <commit> operation without the <confirmed/> parameter. That is, the confirming commit. The confirmed commit allows two parameters: <confirm-timeout> and <persist>. The <confirm-timeout> is the period in seconds before the confirmed commit is reverted, restoring the running configuration to its state before the confirmed commit was issued, unless the confirming commit is issued before or the timeout is reset by another confirmed commit. If the <confirm-timeout> is not specified, the default timeout is 600 seconds. Also, the confirmed commit is reverted if the session is terminated. The <persist> parameter makes the confirmed commit to persist even if the session is terminated. The value of the <persist> parameter is used to identify the confirmed commit from any session, and must be used as the value of the <persist-id> parameter of subsequent confirmed commit or confirming commit.

The following are examples of <commit> request and response messages.

• Commit the contents of the candidate datastore:

  <rpc message-id="113" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <commit/>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="113">
      <ok/>
  </rpc-reply>
  
  

• Confirmed commit with the timeout:

  <rpc message-id="114" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <commit>
          <confirmed/>
          <confirm-timeout>120</confirm-timeout>
      </commit>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="114">
      <ok/>
  </rpc-reply>
  
  

• Start a persistent confirmed commit and then confirm the persistent confirmed commit:

  <rpc message-id="115" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <commit>
          <confirmed/>
          <persist>ID1234</persist>
      </commit>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="115">
      <ok/>
  </rpc-reply>
  
  <!-- confirm the persistent confirmed-commit, from the same session or another session -->
  <rpc message-id="116" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <commit>
          <persist-id>ID1234</persist-id>
      </commit>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="116">
      <ok/>
  </rpc-reply>
  
  

<cancel-commit>

This operation cancels an ongoing confirmed commit. If a confirmed commit from a different session needs to be canceled, the <persist-id> parameter must be used with the same value that was given in the <persist> parameter of the confirmed commit.

• Cancel the confirmed commit from the same sessions:

  <rpc message-id="117" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <cancel-commit/>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="117">
      <ok/>
  </rpc-reply>

<discard-changes>

This operation discards any uncommitted changes that are made on the candidate configuration by resetting back to the content of the running configuration. No parameter is required.

The following is an example of <discard-changes> request and response messages.

• Discard the changes made on the candidate datastore:

  <rpc message-id="118" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <discard-changes/>
  </rpc>
  
  <rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="118">
      <ok/>
  </rpc-reply>
  
  

Connecting Cisco NX-OS with the ncclient

The ncclient is a Python library for NETCONF clients. The following is an example of how to establish a connection to Cisco NX-OS from the ncclient Manager API:

device = {
    "address": "10.10.10.10",
    "netconf_port": 830,
    "username": "admin",
    "password": "cisco"
}
with manager.connect(host = device["address"],
                         port = device["netconf_port"],
                         username = device["username"],
                         password = device["password"],
                         hostkey_verify = False) as m:
    # do your stuff

Using the Sandbox to Generate the NETCONF Payload

Refer to NXAPI Developer Sandbox section to enable it. In order to generate a payload for NETCONF, change the method to RESTCONF (Yang) and message format to XML. Enter the command you need to convert in the text window, click Convert and the equivalent payload is displayed in the Request text box:

Getting Configuration Data from Cisco NX-OS

Here is an example of how to use the ncclient to get the BGP configuration from Cisco NX-OS:

from ncclient import manager
import sys
from lxml import etree

device = {
    "address": "nexus",
    "netconf_port": 830,
    "username": "admin",
    "password": "cisco!"
}


# create a main() method
def main():
    bgp_dom = """
    <filter type="subtree">
        <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
                <bgp-items>
                    <inst-items>
                        <dom-items>
                            <Dom-list/>
                        </dom-items>
                    </inst-items>
                </bgp-items>
        </System>
    </filter>
    """

    with manager.connect(host=device["address"],
                         port=device["netconf_port"],
                         username=device["username"],
                         password=device["password"],
                         hostkey_verify=False) as m:

        # Collect the NETCONF response
        netconf_response = m.get_config(source='running', filter=bgp_dom)
        # Parse the XML and print the data
        xml_data = netconf_response.data_ele
        print(etree.tostring(xml_data, pretty_print=True).decode("utf-8"))


if __name__ == '__main__':
    sys.exit(main())

Getting the Running Configuration and Operational Data from Cisco NX-OS

Here is example of getting the interface counters of all the physical interfaces on Cisco NX-OS:

from ncclient import manager
import sys
from lxml import etree

device = {
    "address": "nexus",
    "netconf_port": 830,
    "username": "admin",
    "password": "cisco"
}


def main():

    intf_ctr_filter = """
    <filter>
        <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
            <intf-items>
                <phys-items>
                <PhysIf-list>
                    <dbgIfIn-items/>
                    <dbgIfOut-items/>
                </PhysIf-list>
                </phys-items>
            </intf-items>
        </System>
    </filter>"""

    with manager.connect(host=device["address"],
                         port=device["netconf_port"],
                         username=device["username"],
                         password=device["password"],
                         hostkey_verify=False) as m:

        # Collect the NETCONF response
        netconf_response = m.get(filter=intf_ctr_filter)
        # Parse the XML and print the data
        xml_data = netconf_response.data_ele
        print(etree.tostring(xml_data, pretty_print=True).decode("utf-8"))

if __name__ == '__main__':
    sys.exit(main())

Creating a New Configuration Using NETCONF

Here is example of how to create VLAN 100 with name using edit config of ncclient:

from ncclient import manager
import sys
from lxml import etree

device = {
    "address": "nexus",
    "netconf_port": 830,
    "username": "admin",
    "password": "cisco"
}


def main():
    add_vlan = """
    <config>
      <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
        <bd-items>
          <bd-items>
            <BD-list>
              <fabEncap>vlan-100</fabEncap>
              <name>inb_mgmt</name>
            </BD-list>
          </bd-items>
        </bd-items>
      </System>
    </config>
    """


    with manager.connect(host=device["address"],
                         port=device["netconf_port"],
                         username=device["username"],
                         password=device["password"],
                         hostkey_verify=False) as m:

        # create vlan with edit_config
        netconf_response = m.edit_config(target="running", config=add_vlan)
        print(netconf_response)

if __name__ == '__main__':
    sys.exit(main())

Deleting Configuration Using NETCONF

Here is example of deleting a loopback interface from Cisco NX-OS:

from ncclient import manager
import sys
from lxml import etree

device = {
    "address": "nexus",
    "netconf_port": 830,
    "username": "admin",
    "password": "cisco"
}


def main():
    remove_loopback = """
    <config>
      <System xmlns="http://cisco.com/ns/yang/cisco-nx-os-device">
        <intf-items>
          <lb-items>
            <LbRtdIf-list operation="delete">
              <id>lo10</id>
            </LbRtdIf-list>
          </lb-items>
        </intf-items>
      </System>
    </config>"""


    with manager.connect(host=device["address"],
                         port=device["netconf_port"],
                         username=device["username"],
                         password=device["password"],
                         hostkey_verify=False) as m:

        # create vlan with edit_config
        netconf_response = m.edit_config(target="running", config=remove_loopback)

        print(netconf_response)

if __name__ == '__main__':
    sys.exit(main())