Dealing with failures

---------------------

While the roles have been designed to be fairly robust, it should be taken into

account that certain handlers are used to bring the system into consistent

state. These handlers are mostly the ones dealing with service restarts, but

there are also a couple of handlers that take care of transforming certain data

into the required formats, import of files etc.

This means that failure to successfully execute such handlers could result in

inconsistent state on the server. Think of service configuration files being

updated, yet the service itself is not restarted and therefore continues to run

with the old configuration.

Handler execution failure can depend on a couple of things, including the loss

of SSH connectivity to managed machine, or some kind of unusual time-out during

handler execution.

To help handle this situation, Majic Ansible Roles all come with a special way

to invoke the handlers explicitly. Each role will include handlers as tasks,

provided that a special variable (``handlers``) is passed in to playbook run. To

make the run shorter, the handlers in such a run are also tagged with

``handlers``. This doubling of environment variable + tagging stems from current

limitations of Ansible (it is not possible to specify that certain task should

be run only if a tag is specified, therefore an additional variable has to be

used).

Handlers alone can be invoked specifically with command similar to::

  ansible-playbook -t handlers -e handlers=true playbook.yml

The ``handlers`` variable is treated as boolean, and by default it is not set.

        state=present user=root

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

  authorized_key: user=root key="{{ ansible_key }}" state=absent

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

---

  when: enable_backup

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

---

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

  when: enable_backup

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

---

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

---

  when: item != "localhost"

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

    - Restart php5-fpm

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers

- name: Explicitly run all handlers

  include: ../handlers/main.yml

  when: "handlers | default(False) | bool() == True"

  tags:

    - handlers