README v3.27 2026-01-29
Table of contents
1. General
1.1 Extract the NED package
1.2 Install the NED package
1.2.1 Local install
1.2.2 System install
1.3 Configure the NED in NSO
2. Optional debug and trace setup
3. Dependencies
4. Sample device configuration
5. Built in live-status actions
6. Built in live-status show
7. Limitations
8. How to report NED issues and feature requests
9. How to rebuild a NED
10. Configure the NED to use ssh multi factor authentication
11. Aflex scripts
12. NED Secrets - Securing your Secrets
13. Device HA configuration considerations1. General
This document describes the a10-acos NED.
Additional README files bundled with this NED package
Common NED Features
Custom NED Features
Verified target systems
1.1 Extract the NED package
It is assumed the NED package ncs-<NSO version>-a10-acos-<NED version>.signed.bin has already been downloaded from software.cisco.com.
In this instruction the following example settings will be used:
NSO version: 6.0
NED version: 1.0.1
NED package downloaded to: /tmp/ned-package-store
Extract the NED package and verify its signature:
In case the signature can not be verified (for instance if no internet connection), do as below instead:
The result of the extraction shall be a tar.gz file with the same name as the .bin file:
1.2 Install the NED package
There are two alternative ways to install this NED package. Which one to use depends on how NSO itself is setup.
In the instructions below the following example settings will be used:
NSO version: 6.0
NED version: 1.0.1
NED download directory: /tmp/ned-package-store
NSO run time directory: ~/nso-lab-rundir
A prerequisite is to set the environment variable NSO_RUNDIR to point at the NSO run time directory:
1.2.1 Local install
This section describes how to install a NED package on a locally installed NSO (see "NSO Local Install" in the NSO Installation guide).
It is assumed the NED package has been been unpacked to a tar.gz file as described in 1.1.
Untar the tar.gz file. This creates a new sub-directory named:
a10-acos-<NED major digit>.<NED minor digit>:Install the NED into NSO, using the ncs-setup tool:
Open a NSO CLI session and load the new NED package like below:
Alternatively the tar.gz file can be installed directly into NSO. Then skip steps 1 and 2 and do like below instead:
Set the environment variable NED_ROOT_DIR to point at the NSO NED package:
1.2.2 System install
This section describes how to install a NED package on a system installed NSO (see "NSO System Install" in the NSO Installation Guide).
It is assumed the NED package has been been unpacked to a tar.gz file as described in 1.1.
Do a NSO backup before installing the new NED package:
Start a NSO CLI session and fetch the NED package:
Install the NED package (add the argument replace-existing if a previous version has been loaded):
Load the NED package
1.3 Configure the NED in NSO
This section describes the steps for configuring a device instance using the newly installed NED package.
Start a NSO CLI session:
Enter configuration mode:
Configure a new authentication group (my-group) to be used for this device:
Configure a new device instance (example: dev-1):
If configured protocol is ssh, do fetch the host keys now:
Finally commit the configuration
Verify configuration, using a sync-from.
If the sync-from was not successful, check the NED configuration again.
2. Optional debug and trace setup
It is often desirable to see details from when and how the NED interacts with the device(Example: troubleshooting)
This can be achieved by configuring NSO to generate a trace file for the NED. A trace file contains information about all interactions with the device. Messages sent and received as well as debug printouts, depending on the log level configured.
NSO creates one separate trace file for each device instance with tracing enabled. Stored in the following location:
$NSO_RUNDIR/logs/ned-a10-acos-cli-1.0-<device name>.trace
Do as follows to enable tracing in one specific device instance in NSO:
Start a NSO CLI session:
Enter configuration mode:
Enable trace raw:
Alternatively, tracing can be enabled globally affecting all configured device instances:
Configure the log level for printouts to the trace file:
Alternatively the log level can be set globally affecting all configured device instances using this NED package.
The log level 'info' is used by default and the 'debug' level is the most verbose.
IMPORTANT: Tracing shall be used with caution. This feature does increase the number of IPC messages sent between the NED and NSO. In some cases this can affect the performance in NSO. Hence, tracing should normally be disabled in production systems.
An alternative method for generating printouts from the NED is to enable the Java logging mechanism. This makes the NED print log messages to common NSO Java log file.
$NSO_RUNDIR/logs/ncs-java-vm.log
Do as follows to enable Java logging in the NED
Start a NSO CLI session:
Enter configuration mode:
Enable Java logging with level all from the NED package:
Configure the NED to log to the Java logger
Alternatively Java logging can be enabled globally affecting all configured device instances using this NED package.
IMPORTANT: Java logging does not use any IPC messages sent to NSO. Consequently, NSO performance is not affected. However, all log printouts from all log enabled devices are saved in one single file. This means that the usability is limited. Typically single device use cases etc.
3. Dependencies
This NED has the following host environment dependencies:
Java 1.8 (NSO version < 6.2)
Java 17 (NSO version >= 6.2)
Gnu Sed
Dependencies for NED recompile:
Apache Ant
Bash
Gnu Sort
Gnu awk
Grep
Python3 (with packages: re, sys, getopt, subprocess, argparse, os, glob)
4. Sample device configuration
The following is an example of configuration data (CLI NED commands) that can be sent to an a10-acos device:
5. Built in live-status actions
There are two main categories of commands that can be sent using a10-acos NED: configuration commands (RPC's that are sent from the device configuration) and privileged commands (RPC's that are sent from privileged mode).
Following RPC's exemplify the two categories:
Each main RPC category also divides in the following sub-categories: simple commands that does not use additional prompts (eg "show configuration"), interactive commands that uses additional prompts (eg a RPC's that requests username/password or any other prompts) and internal NED commands, that does not interact with the device but with the NED.
The last category is supported but not implemented for a specific feature. Simple command format is as follows:
Interactive command contains the simple command and adds the following list:
In the above command, the interaction list defines each prompt that it is expected from the device, along with its corresponding value. Note that prompt-pattern is compiled in a regular expression, so special characters that are expected from prompts should be escaped. The order of the interaction list definition is not important, but all the possible expected prompts should be defined. For example, in the above command, the prompt "Do you want to overwrite.*" is only active when the file exists.
Internal commands looks the same as simple commands, but also contain the keyword "internal":
All the above command sub-categories can be chained and sent in the same request, by defining a list of actions:
The new implementation of RPC action execution allows a more structured way of sending multiple RPC's, by using its XML format:
6. Built in live-status show
The NED does not support TTL-based live-status data
7. Limitations
The NED CLI does not implement the device behavior 1 to 1, since the device is not a netconf-compatible device. Also, the NED may use yang model workarounds (like node alternative naming) in order to support device behavior.
8. How to report NED issues and feature requests
Issues like bugs and errors shall always be reported to the Cisco NSO NED team through the Cisco Support channel:
The following information is required for the Cisco NSO NED team to be able to investigate an issue:
Do as follows to gather the necessary information needed for your device, here named 'dev-1':
Enable full debug logging in the NED
Configure the NSO to generate a raw trace file from the NED
If the NED already had trace enabled, clear it in order to submit only relevant information
Do as follows for NSO 6.4 or newer:
Do as follows for older NSO versions:
Run a compare-config to populate the trace with initial device config
Reproduce the found issue using ncs_cli or your NSO service. Write down each necessary step in a reproduction report.
In addition to this, it helps if you can show how it should work by manually logging into the device using SSH/TELNET and type the relevant commands showing a successful operation.
Gather the reproduction report and a copy of the raw trace file containing data recorded when the issue happened.
Contact the Cisco support and request to open a case. Provide the gathered files together with access details for a device that can be used by the Cisco NSO NED when investigating the issue.
Requests for new features and extensions of the NED are handled by the Cisco NSO NED team when applicable. Such requests shall also go through the Cisco support channel.
The following information is required for feature requests and extensions:
Set the config on the real device including all existing dependent config and run sync-from to show it in the trace.
Run sync-from # devices device dev-1 sync-from
Attach the raw trace to the ticket
List the config you want implemented in the same syntax as shown on the device
SSH/TELNET access to a device that can be used by the Cisco NSO NED team for testing and verification of the new feature. This usually means that both read and write permissions are required. Pseudo access via tools like Webex, Zoom etc is not acceptable. However, it is ok with access through VPNs, jump servers etc as long as we can connect to the NED via SSH/TELNET.
9. How to rebuild a NED
To rebuild the NED do as follows:
When the NED has been successfully rebuilt, it is necessary to reload the package into NSO.
10. Configure the NED to use ssh multi factor authentication
This NED supports multi factor authentication (MFA) using the ssh authentication method 'keyboard-interactive'.
Some additional steps are required to enable the MFA support:
Verify that your NSO version supports MFA. This is configurable as additional settings in the authentication group used by the device instance.
Enter a NSO CLI and enter the following and do tab completion:
If 'mfa' is displayed in the output like above, NSO has MFA support enabled. In case MFA is not supported it is necessary to upgrade NSO before proceeding.
Implement the authenticator executable. The MFA feature relies on an external executable to take care of the client part of the multi factor authentication. The NED will automatically call this executable for each challenge presented by the ssh server and expects to get a proper response in return.
The executable can be a simple shell script or a program implemented in any programming language.
The required behaviour is like this:
read one line from stdin The line passed from the NED will be a semi colon separated string containing the following info:
The elements for device name, user, password and opaque corresponds to what has been configured in NSO. The ssh server name, instruction and prompt are given by the ssh server during the authentication step.
Each individual element in the semi colon separated list is Base64 encoded.
Extract the challenge based on the contents above.
Print a response matching the challenge to stdout and exit with code 0
In case a matching response can not be given do exit with code 2
Below is a simple example of an MFA authenticator implemented in Python3:
Configure the authentication group used by the device instance to enable MFA. There are two configurables available:
executable The path to the external multi factor authentication executable (mandatory).
opaque Opaque data that will passed as a cookie element to the executable (optional).
Try connecting to the device.
10.1 Trouble shooting
In case of connection problems the following steps can help for debugging:
Enable the NED trace in debug level:
Try connect again
Inspect the generated trace file.
Verify that the ssh client is using the external authenticator executable:
Verify that the executable is called with the challenges presented by the ssh server:
Check for any errors reported by the NED when calling the executable
11. Aflex scripts
In order to activate aflex scripts support, run the following command:
Note: after running this command, it is mandatory to do a sync-from, since the device will introduce the aflex section in the running-config
Once the aflex is activated, aflex scripts can be managed. Note: since the device aflex scripts are multi-liners, the script payload needs to be properly escaped by replacing newlines - eg '\n' character with '\n'. Also double quote - eg " needs to be escaped: '"' -> '"' Also, every script should end in a '\n' Note2: since aflex script is a type string leaf in the NED, the script content needs to be quoted:
For example, to create a new script that would look like this on the device:
the equivalent config on the NED will look like this:
Disabling aflex support is done by the following command:
12. NED Secrets - Securing your Secrets
13. Device HA configuration considerations
A10-ACOS devices implements native support for high availability (HA) nodes by configuring one primary device as the active device and 1 to 8 passive devices to mirror the active device configuration and to take over the traffic when the active node becomes unavailable for some reasons. The HA on the targeted devices is configured by properly setting the VRRP-A (A10-ACOS proprietary VRRP protocol) and VCS settings, defining the HA cluster.
In theory, it is possible to fully configure the HA cluster from NSO. However, impacted devices configurations suffer significant changes after HA activation. This means that once the HA is active, the CDB configuration of all involved devices becomes out-of-sync. Moreover, if the passive devices were also configured through NSO, those devices should not be used for future changes, as passive devices in a HA cluster are not allowed to change configuration via its management interface anymore - their configuration is maintained by the active device arbiter.
Here are some examples of configuration changes that will take effect as soon as the HA becomes active:
interfaces numbering - before HA, interfaces look like this:
after HA activation, all interfaces are renamed, adding the device-id before the interface id:
In order to controll certain configuration parts on the nodes of the HA, A10-ACOS devices provides 'device-context' command that allows to switch to a certain device configuration. For instance, it is expected that all the devices have a management interface, each device with its own id. The management interface config would look like this:
It is worth noting that not all the A10-ACOS commands belong in a device-context, but there are certain comands that they will be automatically routed by the device in the appropriate device-context, even if the device-context is not explicitly given. Since the NED is a best-effort implementation of the device behavior, there are certain configuration considerations that have to be taken into account here, otherwise the NED can end up in a compare-config scenario.
For example: 'interface ethernet x' command - although this command can be executed from any device-context, this will directly affect the root configuration of the active device.
on a real device:
In the above example, even if the device-context 2 was activated, the interface ethernet config was routed to root device configuration. This kind of behavior needs to be taken into account in the NED: for instance, a correct configuration of the 'interface ethernet 1/1' would be done in the root device configuration and not in the 'device-context 2' as in the example above.
A similar example (but the other way around) is with the interface management configuration: although it is possible to configure the interface management from root config, the device will route the configuration to the device-context node. For instance, if we configure the following in the NED:
Although the device accepts the interface management change, the device will process the change in the device-context. This can be seen by the following compare-config:
Note: to avoid such a compare-config, one should properly configure the interface management under device-context 1 in the NED. For instance, the following NED config would be a correct commit:
In conclusion, when HA is enabled, special care needs to be taken when configuring the targeted device. As the NED is implemented as a best-effort device support, it is possible to end up in compare-config issues if the configuration is improperly managed from the NED stand point of view. However, with the proper care for the HA configuration, the NED should be able to cover all the HA use-cases.
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