User Guide

GitHub CircleCI PyPi version Documentation Status

Please note that the plugin always collects version and configuration information when mining for network data.

Prerequisites

The plugin requires the presence of two binaries:

  • ssh
  • expect

The users of the plugin should know YAML., because it is the toolkit’s abstraction format.

The toolkit works on Linux. However, it could work on Windows too. If you are interested in Windows support, please open an issue.

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Builtin Commands

This plugin uses the following approach when determining which commands are availble to run on a remote device.

  • First, each device must carry ndmtk_os or os attribute. Based on the value ofthe attribute, the plugin performs a lookup in files/cli/os/ directory the plugin’s directory inside Python’s site-packages directory. For example, Cisco ASA firewall must have either ndmtk_os=cisco_asa or os-cisco_asa attribute.
  • Then, the plugin will try to locate files/cli/os/cisco_asa.yml file. Once located, the plugin will read it and collect all of the cli commands associated with Cisco ASA operating system.

Please note, based on the information, the plugin will also record which commands show configuration and version information, and which commands should be used to disable paging or switch to automation mode.

The disable_defaults option isables default pre-packages commands for various operating systems. It is commonly used when configuring a device, as opposed to gathering data of a device.

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User-Defined Commands

Per Operating System

The cliset_os_dir points to the path to YAML files containing user-defined commands on per operating system basis. The plugin will run the commands only if the plugin is able to locate a file matching a remote host’s operating system in this directory.

For example, if a host’s operating system is cisco_nxos, the plugin will look for cisco_nxos.yml file in this directory. If the file is found, then the plugin will run the commands it found in the file.

Please note that the plugin runs the commands in addition to any default commands, unless they are disabled with disable_defaults.

The default commands for various operating systems are located in <python_site_packages>/ndmtk/files/cli/os directory.

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Per Individual Host

The cliset_host_dir points to the path to YAML files containing user-defined commands on per host basis. The plugin will run the commands only if the plugin is able to locate a file matching a remote host’s hostname in this directory.

For example, if a host’s hostname is ny-fw01, the plugin will look for ny-fw01.yml file in this directory. If the file is present and readable, then the plugin will run the commands it finds in the file.

Please note that the plugin runs the commands in addition to any default commands, unless they are disabled with disable_defaults.

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Specific Tasks

Frequently, there is a need to run a specific set of commands for non-data collection purposes, e.g. device configuration. The cliset_spec points to the path to a single YAML file containing user-defined commands.

As with the previously discussed user-defined commands, the plugin runs the in addition to any default commands, unless they are disabled with disable_defaults.

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Exceptions

The cliset_exc points the path to a single YAML file containing exceptions to both default and user-defined commands. The root element of the YAML data structure is exceptions. The structure is a list of dictionaries/items. Each dictionary item must have at least one of the keys: cli, host, and/or os. The keys are strings containing regular expressions.

The plugin pre-checks each of the commands it has in its queue against the exceptions. If the plugin matches a command with the cli regular expression, it performs additional host and os regular expression searches, if any. If the plugin is able to match all regular expressions within a single exception, it marks the command as skipped and never runs it on the actual device. By default, the plugin search for <ansible_inventory_dir>/files/ndmtk/exceptions.yml file.

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Limits

A user may limit a scope of the commands from any command line set it supplies to the plugin. The user could use sections option.

For example, if a user wants to run only BGP-related commands on a device, the user would add the following to a task sections="bgp". This way, the plugin will only execute the commands that have bgp tag attached to them.

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Data Repository

The plugin uses the value supplied with output option to determine where to store the data produced by the plugin. If a path contains % sign in it, then the plugin performs pre-defined conversions. For example, %h is converted to a host’s hostname, %H to a host’s FQDN, and %E to epoch timestamp. Please search the plugin’s source code for the full list of converted characters.

'h': 'hostname',
'p': 'unique_process_id',
'U': os.path.split(os.path.expanduser('~'))[-1],
'Y': str(ts.tm_year).zfill(4),
'm': str(ts.tm_mon).zfill(2),
'd': str(ts.tm_mday).zfill(2),
'H': str(ts.tm_hour).zfill(2),
'M': str(ts.tm_min).zfill(2),
'S': str(ts.tm_sec).zfill(2),
'E': str(int(epoch)),

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Security

SSH Fingerprints

If the no_host_key_check option is set to yes, it instructs the plugin to accept SSH fingerprints without validation, i.e. trust any SSH fingerprint.

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Jumphosts

The jumphosts instructs the plugin to access devices via a chain of jumphosts. In enterprise networks, access to network devices is allowed only from restricted management stations/hosts. This option allows users to run tasks through these hosts.

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Multi-Factor Authentication (MFA)

Recently, enterprise technology users have been moving to multi-factor authentication (MFA). It presents a challenge to network automation. However, with token_bypass option pointing to the socket of the process with the knowledge iof what that second (multi) factor is, it is no longer an issue.

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Examples

The following command instructs Ansible to login to ny-fw01 and collect running configuration from it.

ansible-playbook playbooks/collect_configuration.yml

Alternatively, a user may collect the output of all relevant operating system commands:

ansible-playbook playbooks/collect_all.yml

Additionally, this plugin supports Check Mode (“Dry Mode”). In this mode, the plugin will not attempt to login to network devices. This mode is used to test for the existence of access credentials.

ansible-playbook playbooks/collect_configuration.yml --check

Another way to use the plugin is to configure network devices. The below Ansible playbook configures ACL on a Cisco ASA firewall.

ansible-playbook playbooks/configure_acl.yml --check -vvv
ansible-playbook playbooks/configure_acl.yml --vvv

This playbook shows how to collecte data via the chaing of devices, i.e controller => 10.1.1.1, 10.1.1.1 => 10.1.2.3, 10.1.2.3 => 10.2.3.4 => managed node.

- name: data collection via jumphosts
  action: |
     ndmtk output="/tmp/jump-data-%Y%m%d%H%M%S"
     jumphosts="10.1.1.1,10.1.2.3,10.2.3.4"
     no_host_key_check=yes

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Common Errors

A user may receive the following error:

fatal: [ny-fw01]: FAILED! => {
    "failed": true,
    "msg": "The module ndmtk was not found in configured module paths.
            Additionally, core modules are missing.
            If this is a checkout, run 'git submodule update --init --recursive'
            to correct this problem."
}

This is the indication that something is broken with setup.py. The issue maybe caused by the lack of permissions. Please open an issue.

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