.. _network_debug_troubleshooting:

***************************************
Network Debug and Troubleshooting Guide
***************************************

.. contents::
   :local:


Introduction
============

Starting with Ansible version 2.1, you can now use the familiar Ansible models of playbook authoring and module development to manage heterogeneous networking devices. Ansible supports a growing number of network devices using both CLI over SSH and API (when available) transports.

This section discusses how to debug and troubleshoot network modules in Ansible 2.3.



How to troubleshoot
===================

This section covers troubleshooting issues with Network Modules.

Errors generally fall into one of the following categories:

:Authentication issues:
  * Not correctly specifying credentials
  * Remote device (network switch/router) not falling back to other other authentication methods
  * SSH key issues
:Timeout issues:
  * Can occur when trying to pull a large amount of data
  * May actually be masking a authentication issue
:Playbook issues:
  * Use of ``delegate_to``, instead of ``ProxyCommand``. See :ref:`network proxy guide <network_delegate_to_vs_ProxyCommand>` for more information.

.. warning:: ``unable to open shell``

  The ``unable to open shell`` message is new in Ansible 2.3, it means that the ``ansible-connection`` daemon has not been able to successfully
  talk to the remote network device. This generally means that there is an authentication issue. See the "Authentication and connection issues" section
  in this document for more information.

.. _enable_network_logging:

Enabling Networking logging and how to read the logfile
-------------------------------------------------------

**Platforms:** Any

Ansible 2.3 features improved logging to help diagnose and troubleshoot issues regarding Ansible Networking modules.

Because logging is very verbose it is disabled by default. It can be enabled via the :envvar:`ANSIBLE_LOG_PATH` and :envvar:`ANSIBLE_DEBUG` options on the ansible-controller, that is the machine running ansible-playbook.

Before running ``ansible-playbook`` run the following commands to enable logging::

   # Specify the location for the log file
   export ANSIBLE_LOG_PATH=~/ansible.log
   # Enable Debug
   export ANSIBLE_DEBUG=True

   # Run with 4*v for connection level verbosity
   ansible-playbook -vvvv ...

After Ansible has finished running you can inspect the log file which has been created on the ansible-controller:

.. code::

  less $ANSIBLE_LOG_PATH

  2017-03-30 13:19:52,740 p=28990 u=fred |  creating new control socket for host veos01:22 as user admin
  2017-03-30 13:19:52,741 p=28990 u=fred |  control socket path is /home/fred/.ansible/pc/ca5960d27a
  2017-03-30 13:19:52,741 p=28990 u=fred |  current working directory is /home/fred/ansible/test/integration
  2017-03-30 13:19:52,741 p=28990 u=fred |  using connection plugin network_cli
  ...
  2017-03-30 13:20:14,771 paramiko.transport userauth is OK
  2017-03-30 13:20:15,283 paramiko.transport Authentication (keyboard-interactive) successful!
  2017-03-30 13:20:15,302 p=28990 u=fred |  ssh connection done, setting terminal
  2017-03-30 13:20:15,321 p=28990 u=fred |  ssh connection has completed successfully
  2017-03-30 13:20:15,322 p=28990 u=fred |  connection established to veos01 in 0:00:22.580626


From the log notice:

* ``p=28990`` Is the PID (Process ID) of the ``ansible-connection`` process
* ``u=fred`` Is the user `running` ansible, not the remote-user you are attempting to connect as
* ``creating new control socket for host veos01:22 as user admin`` host:port as user
* ``control socket path is`` location on disk where the persistent connection socket is created
* ``using connection plugin network_cli`` Informs you that persistent connection is being used
* ``connection established to veos01 in 0:00:22.580626`` Time taken to obtain a shell on the remote device


.. note: Port None ``creating new control socket for host veos01:None``

   If the log reports the port as ``None`` this means that the default port is being used.
   A future Ansible release will improve this message so that the port is always logged.

Because the log files are verbose, you can use grep to look for specific information. For example, once you have identified the ``pid`` from the ``creating new control socket for host`` line you can search for other connection log entries::

  grep "p=28990" $ANSIBLE_LOG_PATH


Enabling Networking device interaction logging
----------------------------------------------

**Platforms:** Any

Ansible 2.8 features added logging of device interaction in log file to help diagnose and troubleshoot
issues regarding Ansible Networking modules. The messages are logged in file pointed by ``log_path`` configuration
option in Ansible configuration file or by set :envvar:`ANSIBLE_LOG_PATH` as mentioned in above section.

.. warning::
  The device interaction messages consist of command executed on target device and the returned response, as this
  log data can contain sensitive information including passwords in plain text it is disabled by default.
  Additionally, in order to prevent accidental leakage of data, a warning will be shown on every task with this
  setting enabled specifying which host has it enabled and where the data is being logged.

Be sure to fully understand the security implications of enabling this option. The device interaction logging can be enabled either globally by setting in configuration file or by setting environment or enabled on per task basis by passing special variable to task.

Before running ``ansible-playbook`` run the following commands to enable logging::

   # Specify the location for the log file
   export ANSIBLE_LOG_PATH=~/ansible.log


Enable device interaction logging for a given task

.. code-block:: yaml

  - name: get version information
    ios_command:
      commands:
        - show version
    vars:
      ansible_persistent_log_messages: True


To make this a global setting, add the following to your ``ansible.cfg`` file:

.. code-block:: ini

   [persistent_connection]
   log_messages = True

or enable environment variable `ANSIBLE_PERSISTENT_LOG_MESSAGES`

   # Enable device interaction logging
   export ANSIBLE_PERSISTENT_LOG_MESSAGES=True

If the task is failing at the time on connection initialization itself it is recommended to enable this option
globally else if an individual task is failing intermittently this option can be enabled for that task itself to
find the root cause.

After Ansible has finished running you can inspect the log file which has been created on the ansible-controller

.. note:: Be sure to fully understand the security implications of enabling this option as it can log sensitive
          information in log file thus creating security vulnerability.


Isolating an error
------------------

**Platforms:** Any

As with any effort to troubleshoot it's important to simplify the test case as much as possible.

For Ansible this can be done by ensuring you are only running against one remote device:

* Using ``ansible-playbook --limit switch1.example.net...``
* Using an ad-hoc ``ansible`` command

`ad-hoc` refers to running Ansible to perform some quick command using ``/usr/bin/ansible``, rather than the orchestration language, which is ``/usr/bin/ansible-playbook``. In this case we can ensure connectivity by attempting to execute a single command on the remote device::

  ansible -m eos_command -a 'commands=?' -i inventory switch1.example.net -e 'ansible_connection=local' -u admin -k

In the above example, we:

* connect to ``switch1.example.net`` specified in the inventory file ``inventory``
* use the module ``eos_command``
* run the command ``?``
* connect using the username ``admin``
* inform ansible to prompt for the ssh password by specifying ``-k``

If you have SSH keys configured correctly, you don't need to specify the ``-k`` parameter

If the connection still fails you can combine it with the enable_network_logging parameter. For example::

   # Specify the location for the log file
   export ANSIBLE_LOG_PATH=~/ansible.log
   # Enable Debug
   export ANSIBLE_DEBUG=True
   # Run with 4*v for connection level verbosity
   ansible -m eos_command -a 'commands=?' -i inventory switch1.example.net -e 'ansible_connection=local' -u admin -k

Then review the log file and find the relevant error message in the rest of this document.

.. For details on other ways to authenticate, see LINKTOAUTHHOWTODOCS.

.. _socket_path_issue:

Category "socket_path issue"
============================

**Platforms:** Any

The ``socket_path does not exist or cannot be found``  and ``unable to connect to socket`` messages are new in Ansible 2.5. These messages indicate that the socket used to communicate with the remote network device is unavailable or does not exist.


For example:

.. code-block:: none

   fatal: [spine02]: FAILED! => {
       "changed": false,
       "failed": true,
       "module_stderr": "Traceback (most recent call last):\n  File \"/tmp/ansible_TSqk5J/ansible_modlib.zip/ansible/module_utils/connection.py\", line 115, in _exec_jsonrpc\nansible.module_utils.connection.ConnectionError: socket_path does not exist or cannot be found\n",
       "module_stdout": "",
       "msg": "MODULE FAILURE",
       "rc": 1
   }

or

.. code-block:: none

   fatal: [spine02]: FAILED! => {
       "changed": false,
       "failed": true,
       "module_stderr": "Traceback (most recent call last):\n  File \"/tmp/ansible_TSqk5J/ansible_modlib.zip/ansible/module_utils/connection.py\", line 123, in _exec_jsonrpc\nansible.module_utils.connection.ConnectionError: unable to connect to socket\n",
       "module_stdout": "",
       "msg": "MODULE FAILURE",
       "rc": 1
   }

Suggestions to resolve:

Follow the steps detailed in :ref:`enable network logging <enable_network_logging>`.

If the identified error message from the log file is:

.. code-block:: yaml

   2017-04-04 12:19:05,670 p=18591 u=fred |  command timeout triggered, timeout value is 30 secs

or

.. code-block:: yaml

   2017-04-04 12:19:05,670 p=18591 u=fred |  persistent connection idle timeout triggered, timeout value is 30 secs

Follow the steps detailed in :ref:`timeout issues <timeout_issues>`


.. _unable_to_open_shell:

Category "Unable to open shell"
===============================


**Platforms:** Any

The ``unable to open shell`` message is new in Ansible 2.3. This message means that the ``ansible-connection`` daemon has not been able to successfully talk to the remote network device. This generally means that there is an authentication issue. It is a "catch all" message, meaning you need to enable :ref:logging`a_note_about_logging` to find the underlying issues.



For example:

.. code-block:: none

  TASK [prepare_eos_tests : enable cli on remote device] **************************************************
  fatal: [veos01]: FAILED! => {"changed": false, "failed": true, "msg": "unable to open shell"}


or:


.. code-block:: none

   TASK [ios_system : configure name_servers] *************************************************************
   task path:
   fatal: [ios-csr1000v]: FAILED! => {
       "changed": false,
       "failed": true,
       "msg": "unable to open shell",
   }

Suggestions to resolve:

Follow the steps detailed in enable_network_logging_.

Once you've identified the error message from the log file, the specific solution can be found in the rest of this document.



Error: "[Errno -2] Name or service not known"
---------------------------------------------

**Platforms:** Any

Indicates that the remote host you are trying to connect to can not be reached

For example:

.. code-block:: yaml

   2017-04-04 11:39:48,147 p=15299 u=fred |  control socket path is /home/fred/.ansible/pc/ca5960d27a
   2017-04-04 11:39:48,147 p=15299 u=fred |  current working directory is /home/fred/git/ansible-inc/stable-2.3/test/integration
   2017-04-04 11:39:48,147 p=15299 u=fred |  using connection plugin network_cli
   2017-04-04 11:39:48,340 p=15299 u=fred |  connecting to host veos01 returned an error
   2017-04-04 11:39:48,340 p=15299 u=fred |  [Errno -2] Name or service not known


Suggestions to resolve:

* If you are using the ``provider:`` options ensure that its suboption ``host:`` is set correctly.
* If you are not using ``provider:`` nor top-level arguments ensure your inventory file is correct.





Error: "Authentication failed"
------------------------------

**Platforms:** Any

Occurs if the credentials (username, passwords, or ssh keys) passed to ``ansible-connection`` (via ``ansible`` or ``ansible-playbook``) can not be used to connect to the remote device.



For example:

.. code-block:: yaml

   <ios01> ESTABLISH CONNECTION FOR USER: cisco on PORT 22 TO ios01
   <ios01> Authentication failed.


Suggestions to resolve:

If you are specifying credentials via ``password:`` (either directly or via ``provider:``) or the environment variable `ANSIBLE_NET_PASSWORD` it is possible that ``paramiko`` (the Python SSH library that Ansible uses) is using ssh keys, and therefore the credentials you are specifying are being ignored. To find out if this is the case, disable "look for keys". This can be done like this:

.. code-block:: yaml

   export ANSIBLE_PARAMIKO_LOOK_FOR_KEYS=False

To make this a permanent change, add the following to your ``ansible.cfg`` file:

.. code-block:: ini

   [paramiko_connection]
   look_for_keys = False


Error: "connecting to host <hostname> returned an error" or "Bad address"
-------------------------------------------------------------------------

This may occur if the SSH fingerprint hasn't been added to Paramiko's (the Python SSH library) know hosts file.

When using persistent connections with Paramiko, the connection runs in a background process.  If the host doesn't already have a valid SSH key, by default Ansible will prompt to add the host key.  This will cause connections running in background processes to fail.

For example:

.. code-block:: yaml

   2017-04-04 12:06:03,486 p=17981 u=fred |  using connection plugin network_cli
   2017-04-04 12:06:04,680 p=17981 u=fred |  connecting to host veos01 returned an error
   2017-04-04 12:06:04,682 p=17981 u=fred |  (14, 'Bad address')
   2017-04-04 12:06:33,519 p=17981 u=fred |  number of connection attempts exceeded, unable to connect to control socket
   2017-04-04 12:06:33,520 p=17981 u=fred |  persistent_connect_interval=1, persistent_connect_retries=30


Suggestions to resolve:

Use ``ssh-keyscan`` to pre-populate the known_hosts. You need to ensure the keys are correct.

.. code-block:: shell

   ssh-keyscan veos01


or

You can tell Ansible to automatically accept the keys

Environment variable method::

  export ANSIBLE_PARAMIKO_HOST_KEY_AUTO_ADD=True
  ansible-playbook ...

``ansible.cfg`` method:

ansible.cfg

.. code-block:: ini

  [paramiko_connection]
  host_key_auto_add = True



.. warning: Security warning

   Care should be taken before accepting keys.

Error: "No authentication methods available"
--------------------------------------------

For example:

.. code-block:: yaml

   2017-04-04 12:19:05,670 p=18591 u=fred |  creating new control socket for host veos01:None as user admin
   2017-04-04 12:19:05,670 p=18591 u=fred |  control socket path is /home/fred/.ansible/pc/ca5960d27a
   2017-04-04 12:19:05,670 p=18591 u=fred |  current working directory is /home/fred/git/ansible-inc/ansible-workspace-2/test/integration
   2017-04-04 12:19:05,670 p=18591 u=fred |  using connection plugin network_cli
   2017-04-04 12:19:06,606 p=18591 u=fred |  connecting to host veos01 returned an error
   2017-04-04 12:19:06,606 p=18591 u=fred |  No authentication methods available
   2017-04-04 12:19:35,708 p=18591 u=fred |  connect retry timeout expired, unable to connect to control socket
   2017-04-04 12:19:35,709 p=18591 u=fred |  persistent_connect_retry_timeout is 15 secs


Suggestions to resolve:

No password or SSH key supplied

Clearing Out Persistent Connections
-----------------------------------

**Platforms:** Any

In Ansible 2.3, persistent connection sockets are stored in ``~/.ansible/pc`` for all network devices.  When an Ansible playbook runs, the persistent socket connection is displayed when verbose output is specified.

``<switch> socket_path: /home/fred/.ansible/pc/f64ddfa760``

To clear out a persistent connection before it times out (the default timeout is 30 seconds
of inactivity), simple delete the socket file.


.. _timeout_issues:

Timeout issues
==============

Persistent connection idle timeout
----------------------------------

By default, ``ANSIBLE_PERSISTENT_CONNECT_TIMEOUT`` is set to 30 (seconds). You may see the following error if this value is too low:

.. code-block:: yaml

   2017-04-04 12:19:05,670 p=18591 u=fred |  persistent connection idle timeout triggered, timeout value is 30 secs

Suggestions to resolve:

Increase value of persistent connection idle timeout:

.. code-block:: sh

   export ANSIBLE_PERSISTENT_CONNECT_TIMEOUT=60

To make this a permanent change, add the following to your ``ansible.cfg`` file:

.. code-block:: ini

   [persistent_connection]
   connect_timeout = 60

Command timeout
---------------

By default, ``ANSIBLE_PERSISTENT_COMMAND_TIMEOUT`` is set to 30 (seconds). Prior versions of Ansible had this value set to 10 seconds by default.
You may see the following error if this value is too low:


.. code-block:: yaml

   2017-04-04 12:19:05,670 p=18591 u=fred |  command timeout triggered, timeout value is 30 secs

Suggestions to resolve:

* Option 1 (Global command timeout setting):
  Increase value of command timeout in configuration file or by setting environment variable.

  .. code-block:: yaml

     export ANSIBLE_PERSISTENT_COMMAND_TIMEOUT=60

  To make this a permanent change, add the following to your ``ansible.cfg`` file:

  .. code-block:: ini

     [persistent_connection]
     command_timeout = 60

* Option 2 (Per task command timeout setting):
  Increase command timeout per task basis. All network modules support a
  timeout value that can be set on a per task basis.
  The timeout value controls the amount of time in seconds before the
  task will fail if the command has not returned.

  For local connection type:

  .. FIXME: Detail error here

  Suggestions to resolve:

  .. code-block:: yaml

      - name: save running-config
        ios_command:
          commands: copy running-config startup-config
          provider: "{{ cli }}"
          timeout: 30

  For network_cli, netconf connection type (applicable from 2.7 onwards):

  .. FIXME: Detail error here

  Suggestions to resolve:

  .. code-block:: yaml

      - name: save running-config
        ios_command:
          commands: copy running-config startup-config
        vars:
          ansible_command_timeout: 60

Some operations take longer than the default 30 seconds to complete.  One good
example is saving the current running config on IOS devices to startup config.
In this case, changing the timeout value from the default 30 seconds to 60
seconds will prevent the task from failing before the command completes
successfully.

Persistent connection retry timeout
-----------------------------------

By default, ``ANSIBLE_PERSISTENT_CONNECT_RETRY_TIMEOUT`` is set to 15 (seconds). You may see the following error if this value is too low:

.. code-block:: yaml

   2017-04-04 12:19:35,708 p=18591 u=fred |  connect retry timeout expired, unable to connect to control socket
   2017-04-04 12:19:35,709 p=18591 u=fred |  persistent_connect_retry_timeout is 15 secs

Suggestions to resolve:

Increase the value of the persistent connection idle timeout.
Note: This value should be greater than the SSH timeout value (the timeout value under the defaults
section in the configuration file) and less than the value of the persistent
connection idle timeout (connect_timeout).

.. code-block:: yaml

   export ANSIBLE_PERSISTENT_CONNECT_RETRY_TIMEOUT=30

To make this a permanent change, add the following to your ``ansible.cfg`` file:

.. code-block:: ini

   [persistent_connection]
   connect_retry_timeout = 30


Timeout issue due to platform specific login menu with ``network_cli`` connection type
--------------------------------------------------------------------------------------

In Ansible 2.9 and later, the network_cli connection plugin configuration options are added
to handle the platform specific login menu. These options can be set as group/host or tasks
variables.

Example: Handle single login menu prompts with host variables

.. code-block:: console

    $cat host_vars/<hostname>.yaml
    ---
    ansible_terminal_initial_prompt:
      - "Connect to a host"
    ansible_terminal_initial_answer:
      - "3"

Example: Handle remote host multiple login menu prompts with host variables

.. code-block:: console

    $cat host_vars/<inventory-hostname>.yaml
    ---
    ansible_terminal_initial_prompt:
      - "Press any key to enter main menu"
      - "Connect to a host"
    ansible_terminal_initial_answer:
      - "\\r"
      - "3"
    ansible_terminal_initial_prompt_checkall: True

To handle multiple login menu prompts:

* The values of ``ansible_terminal_initial_prompt`` and ``ansible_terminal_initial_answer`` should be a list.
* The prompt sequence should match the answer sequence.
* The value of ``ansible_terminal_initial_prompt_checkall`` should be set to ``True``.

.. note:: If all the prompts in sequence are not received from remote host at the time connection initialization it will result in a timeout.


Playbook issues
===============

This section details issues are caused by issues with the Playbook itself.

Error: "Unable to enter configuration mode"
-------------------------------------------

**Platforms:** eos and ios

This occurs when you attempt to run a task that requires privileged mode in a user mode shell.

For example:

.. code-block:: console

  TASK [ios_system : configure name_servers] *****************************************************************************
  task path:
  fatal: [ios-csr1000v]: FAILED! => {
      "changed": false,
      "failed": true,
     "msg": "unable to enter configuration mode",
  }

Suggestions to resolve:

In Ansible prior to 2.5 :
Add ``authorize: yes`` to the task. For example:

.. code-block:: yaml

  - name: configure hostname
    ios_system:
      provider:
        hostname: foo
        authorize: yes
    register: result

If the user requires a password to go into privileged mode, this can be specified with ``auth_pass``; if ``auth_pass`` isn't set, the environment variable `ANSIBLE_NET_AUTHORIZE` will be used instead.


Add ``authorize: yes`` to the task. For example:

.. code-block:: yaml

  - name: configure hostname
    ios_system:
    provider:
      hostname: foo
      authorize: yes
      auth_pass: "{{ mypasswordvar }}"
  register: result


.. note:: Starting with Ansible 2.5 we recommend using ``connection: network_cli`` and ``become: yes``


Proxy Issues
============

 .. _network_delegate_to_vs_ProxyCommand:

delegate_to vs ProxyCommand
---------------------------

The new connection framework for Network Modules in Ansible 2.3 that uses ``cli`` transport
no longer supports the use of the ``delegate_to`` directive.
In order to use a bastion or intermediate jump host to connect to network devices over ``cli``
transport, network modules now support the use of ``ProxyCommand``.

To use ``ProxyCommand``, configure the proxy settings in the Ansible inventory
file to specify the proxy host.

.. code-block:: ini

    [nxos]
    nxos01
    nxos02

    [nxos:vars]
    ansible_ssh_common_args='-o ProxyCommand="ssh -W %h:%p -q bastion01"'


With the configuration above, simply build and run the playbook as normal with
no additional changes necessary.  The network module will now connect to the
network device by first connecting to the host specified in
``ansible_ssh_common_args``, which is ``bastion01`` in the above example.

You can also set the proxy target for all hosts by using environment variables.

.. code-block:: sh

    export ANSIBLE_SSH_ARGS='-o ProxyCommand="ssh -W %h:%p -q bastion01"'

Using bastion/jump host with netconf connection
-----------------------------------------------

Enabling jump host setting
--------------------------


Bastion/jump host with netconf connection can be enabled by:
 - Setting Ansible variable ``ansible_netconf_ssh_config`` either to ``True`` or custom ssh config file path
 - Setting environment variable ``ANSIBLE_NETCONF_SSH_CONFIG`` to ``True`` or custom ssh config file path
 - Setting ``ssh_config = 1`` or ``ssh_config = <ssh-file-path>`` under ``netconf_connection`` section

If the configuration variable is set to 1 the proxycommand and other ssh variables are read from
default ssh config file (~/.ssh/config).

If the configuration variable is set to file path the proxycommand and other ssh variables are read
from the given custom ssh file path

Example ssh config file (~/.ssh/config)
---------------------------------------

.. code-block:: ini

  Host jumphost
    HostName jumphost.domain.name.com
    User jumphost-user
    IdentityFile "/path/to/ssh-key.pem"
    Port 22

  # Note: Due to the way that Paramiko reads the SSH Config file,
  # you need to specify the NETCONF port that the host uses.
  # i.e. It does not automatically use ansible_port
  # As a result you need either:

  Host junos01
    HostName junos01
    ProxyCommand ssh -W %h:22 jumphost

  # OR

  Host junos01
    HostName junos01
    ProxyCommand ssh -W %h:830 jumphost

  # Depending on the netconf port used.

Example Ansible inventory file

.. code-block:: ini

    [junos]
    junos01

    [junos:vars]
    ansible_connection=netconf
    ansible_network_os=junos
    ansible_user=myuser
    ansible_password=!vault...


.. note:: Using ``ProxyCommand`` with passwords via variables

   By design, SSH doesn't support providing passwords via environment variables.
   This is done to prevent secrets from leaking out, for example in ``ps`` output.

   We recommend using SSH Keys, and if needed an ssh-agent, rather than passwords, where ever possible.

Miscellaneous Issues
====================


Intermittent failure while using ``network_cli`` connection type
----------------------------------------------------------------

If the command prompt received in response is not matched correctly within
the ``network_cli`` connection plugin the task might fail intermittently with truncated
response or with the error message ``operation requires privilege escalation``.
Starting in 2.7.1 a new buffer read timer is added to ensure prompts are matched properly
and a complete response is send in output. The timer default value is 0.2 seconds and
can be adjusted on a per task basis or can be set globally in seconds.

Example Per task timer setting

.. code-block:: yaml

  - name: gather ios facts
    ios_facts:
      gather_subset: all
    register: result
    vars:
      ansible_buffer_read_timeout: 2


To make this a global setting, add the following to your ``ansible.cfg`` file:

.. code-block:: ini

   [persistent_connection]
   buffer_read_timeout = 2

This timer delay per command executed on remote host can be disabled by setting the value to zero.


Task failure due to mismatched error regex within command response using ``network_cli`` connection type
--------------------------------------------------------------------------------------------------------

In Ansible 2.9 and later, the network_cli connection plugin configuration options are added
to handle the stdout and stderr regex to identify if the command execution response consist
of a normal response or an error response. These options can be set group/host variables or as
tasks variables.

Example: For mismatched error response

.. code-block:: yaml

  - name: fetch logs from remote host
    ios_command:
      commands:
        - show logging


Playbook run output:

.. code-block:: console

  TASK [first fetch logs] ********************************************************
  fatal: [ios01]: FAILED! => {
      "changed": false,
      "msg": "RF Name:\r\n\r\n <--nsip-->
             \"IPSEC-3-REPLAY_ERROR: Test log\"\r\n*Aug  1 08:36:18.483: %SYS-7-USERLOG_DEBUG:
              Message from tty578(user id: ansible): test\r\nan-ios-02#"}

Suggestions to resolve:

Modify the error regex for individual task.

.. code-block:: yaml

  - name: fetch logs from remote host
    ios_command:
      commands:
        - show logging
    vars:
      ansible_terminal_stderr_re:
        - pattern: 'connection timed out'
          flags: 're.I'

The terminal plugin regex options ``ansible_terminal_stderr_re`` and ``ansible_terminal_stdout_re`` have
``pattern`` and ``flags`` as keys. The value of the ``flags`` key should be a value that is accepted by
the ``re.compile`` python method.


Intermittent failure while using ``network_cli`` connection type due to slower network or remote target host
------------------------------------------------------------------------------------------------------------

In Ansible 2.9 and later, the ``network_cli`` connection plugin configuration option is added to control
the number of attempts to connect to a remote host. The default number of attempts is three.
After every retry attempt the delay between retries is increased by power of 2 in seconds until either the
maximum attempts are exhausted or either the ``persistent_command_timeout`` or ``persistent_connect_timeout`` timers are triggered.

To make this a global setting, add the following to your ``ansible.cfg`` file:

.. code-block:: ini

   [persistent_connection]
   network_cli_retries = 5
