.. _2.2-error-handling:

Exercise 2.2: Using a combination of modules to perform a graceful rollback
###########################################################################

Objective
=========

Demonstrate use of the different modules to perform a rollback of the
configuration on the BIG-IP.

Guide
=====

Step 1
------

Use VS Code Explorer to create a new file called ``bigip-error-handling.yml``.

..

   The Ansible node is equiped with ``Visual Studio Code`` and can be accessed via UDF ACCESS Methods.

Step 2
------

Enter the following play definition into ``bigip-error-handling.yml``:

.. code-block:: yaml

   ---
   - name: BIG-IP SETUP
     hosts: lb
     connection: local
     gather_facts: false

-  The ``---`` at the top of the file indicates that this is a YAML
   file.
-  The ``hosts: f5``, indicates the play is run only on the F5 BIG-IP
   device
-  ``connection: local`` tells the Playbook to run locally (rather than
   SSHing to itself)
-  ``gather_facts: false`` disables facts gathering. We are not using
   any fact variables for this playbook.

Step 3
------

Add a tasks section with a set_fact for setting the provider values

.. code-block:: yaml

   tasks:

       - name: Setup provider
         set_fact:
          provider:
           server: "{{private_ip}}"
           user: "{{ansible_user}}"
           password: "{{ansible_ssh_pass}}"
           server_port: "8443"
           validate_certs: "no"

Step 4
------

Next, add the ``block`` stanza and the first ``task``. The first task
will be the bigip_node as performed in :ref:`Exercise 1.2 - Adding nodes 
to F5 BIG-IP <1.2-add-node>`.

.. code-block:: yaml

    - name: Setup and graceful rollback BIG-IP configuration
      block:
        - name: CREATE NODES
          bigip_node:
           provider: "{{provider}}"
           host: "{{hostvars[item].ansible_host}}"
           name: "{{hostvars[item].inventory_hostname}}"
          loop: "{{ groups['webservers'] }}"

Step 5
------

Next, add the second task for bigip_pool as demonstrated in :ref:`Exercise
1.3 - Adding a load balancing pool <1.3-add-pool>`.

.. code-block:: yaml

           - name: CREATE POOL
             bigip_pool:
               provider: "{{provider}}"
               name: "http_pool"
               lb_method: "round-robin"
               monitors: "/Common/http"
               monitor_type: "and_list"

Step 6
------

Next, add the third task. For the third task use the bigip_pool_member
as demonstrated in :ref:`Exercise 1.4 - Adding members to a
pool<1.4-add-pool-members>`.

.. code-block:: yaml

           - name: ADD POOL MEMBERS
             bigip_pool_member:
              provider: "{{provider}}"
              state: "present"
              name: "{{hostvars[item].inventory_hostname}}"
              host: "{{hostvars[item].ansible_host}}"
              port: "80"
              pool: "http_pool"
             loop: "{{ groups['webservers'] }}"

Step 7
------

Next, add the fourth task. For the fourth task use the
bigip_virtual_server as demonstrated in :ref:`Exercise 1.5 - Adding a virtual
server<1.5-add-virtual-server>`.

.. code-block:: yaml

           - name: ADD VIRTUAL SERVER
             bigip_virtual_server:
              provider: "{{provider}}"
              name: "vip"
              destination: "{{private_ip}}"
              port: "443"
              enabled_vlans: "all"
              all_profiles: ['http','clientssl','oneconnect']
              pool: "http_pool"
              snat: "Automap1"

.. _step-7-1:

Step 7
------

Next, add the **rescue** stanza. The tasks under the ``rescue`` stanza
will be identical to :ref:`Exercise 1.6 - Deleting F5 BIG-IP
Configuration<1.6-add-irules>`. The
bigip_pool_member task does not need to re-enterered since by deleting
the nodes and pool will remove all configuration. If any task within the
**block** fails, the **rescue** stanza will execute in order. The VIP,
pool, and nodes will be removed gracefully.

.. code-block:: yaml

         rescue:

           - name: DELETE VIRTUAL SERVER
             bigip_virtual_server:
               provider: "{{provider}}"
               name: "vip"
               state: absent

           - name: DELETE POOL
             bigip_pool:
               provider: "{{provider}}"
               name: "http_pool"
               state: absent

           - name: DELETE NODES
             bigip_node:
               provider: "{{provider}}"
               name: "{{hostvars[item].inventory_hostname}}"
               state: absent
             loop: "{{ groups['webservers'] }}"

Step 8
------

Finally add the **always** to save the running configuration.

.. code-block:: yaml

   ---
   - name: BIG-IP SETUP
     hosts: lb
     connection: local
     gather_facts: false

     tasks:
       - name: Setup provider
         set_fact:
          provider:
           server: "{{private_ip}}"
           user: "{{ansible_user}}"
           password: "{{ansible_ssh_pass}}"
           server_port: "8443"
           validate_certs: "no"

       - name: SETUP AND GRACEFUL ROLLBACK BIG-IP CONFIGURATION
         block:
           - name: CREATE NODES
             bigip_node:
               provider: "{{provider}}"
               host: "{{hostvars[item].ansible_host}}"
               name: "{{hostvars[item].inventory_hostname}}"
             loop: "{{ groups['webservers'] }}"

           - name: CREATE POOL
             bigip_pool:
               provider: "{{provider}}"
               name: "http_pool"
               lb_method: "round-robin"
               monitors: "/Common/http"
               monitor_type: "and_list"

           - name: ADD POOL MEMBERS
             bigip_pool_member:
               provider: "{{provider}}"
               state: "present"
               name: "{{hostvars[item].inventory_hostname}}"
               host: "{{hostvars[item].ansible_host}}"
               port: "80"
               pool: "http_pool"
             loop: "{{ groups['webservers'] }}"

           - name: ADD VIRTUAL SERVER
             bigip_virtual_server:
               provider: "{{provider}}"
               name: "vip"
               destination: "{{private_ip}}"
               port: "443"
               enabled_vlans: "all"
               all_profiles: ['http','clientssl','oneconnect']
               pool: "http_pool"
               snat: "Automap1"

         rescue:

           - name: DELETE VIRTUAL SERVER
             bigip_virtual_server:
               provider: "{{provider}}"
               name: "vip"
               state: absent

           - name: DELETE POOL
             bigip_pool:
               provider: "{{provider}}"
               name: "http_pool"
               state: absent

           - name: DELETE NODES
             bigip_node:
               provider: "{{provider}}"
               name: "{{hostvars[item].inventory_hostname}}"
               state: absent
             loop: "{{ groups['webservers'] }}"
         always:
           - name: SAVE RUNNING CONFIGURATION
             bigip_config:
               provider: "{{provider}}"
               save: yes

The above playbook will try and configure the Virtual Server, Pool and
Nodes but since the snat value is provided as ‘Automap1’ the addition of
virtual server will fail and the ‘rescue’ block will be run.

Step 9
------

Run the playbook - exit back into the command line of the control host
and execute the following:

.. code-block:: shell-session

   [centos@ansible ~]$ ansible-playbook bigip-error-handling.yml

Playbook Output
===============

.. code-block:: shell-session

   [centos@ansible ~]$ ansible-playbook bigip-error-handling.yml

   [centos@ansible ~]$ ansible-playbook bigip-error-handling.yml

   PLAY [BIG-IP SETUP] ****************************************************************************************************

   TASK [Setup provider] **************************************************************************************************
   ok: [f5]

   TASK [CREATE NODES] *****************************************************************************************************
   changed: [f5] => (item=host1)
   changed: [f5] => (item=host2)

   TASK [CREATE POOL] *******************************************************************************************************
   changed: [f5]

   TASK [ADD POOL MEMBERS] **************************************************************************************************************************
   changed: [f5] => (item=host1)
   changed: [f5] => (item=host2)

   TASK [ADD VIRTUAL SERVER] ***************************************************************************************************************************
   fatal: [f5]: FAILED! => {"changed": false, "msg": "0107163f:3: Pool (/Common/Automap1) of type (snatpool) doesn't exist."}

   TASK [DELETE VIRTUAL SERVER] **************************************************************************************************************************
   ok: [f5]

   TASK [DELETE POOL] **************************************************************************************************************************
   changed: [f5]

   TASK [DELETE NODES] **************************************************************************************************************************
   changed: [f5] => (item=host1)
   changed: [f5] => (item=host2)

   TASK [SAVE RUNNING CONFIGURATION] ***************************************************************************************************************************
   changed: [f5]

   PLAY RECAP *****************************************************************************************************************
   f5                         : ok=8    changed=6    unreachable=0    failed=1


Notice that without the declarative error handling, the Ansible playbook would have stopped here.

.. figure:: error.png

The work you have been saved is that you don't need to clean the config at the BIG-IP. 
This declarative ``bigip-error-handling.yml`` Ansible playbook has this done for you.

Check the BIG-IP by login to the GUI and check the Local Traffic configuration.

Solution
========

The finished Ansible Playbook is provided here for an Answer key. Click
here: :download:`bigip-error-handling.yml <./bigip-error-handling.yml>`.

You have finished this exercise. `Click here to return to the lab
guide <..>`__