Run handler on failed task

[Joachim Friberg]

Hi,

So what I want to do, and have not yet found a way todo yet, is to run a handler if a taks fails rather then if it succeeds.

For example I want to do a yum install mysql on a server, but this server does not have python-simplejson and/or other packages that is neccesary for Ansible.

How do I then trigger a "fix" and then preferably rerun the failed task. Is this possible?

Something similar to:

- hosts: mysql

  user: admin

  vars:

    passwd: VeryHardPasswd

    user: analytics

  tasks:

  - name: create user Analytics

    mysql_user: name={{ user }}

                password={{ passwd }}

                priv=*.*:SELECT,'SHOW DATABASES'

                state=present

                login_user=ROOT

                login_password=PASSWORD

    register: mysql_result

    ignore_errors: True

   notify_on_fail: install mysqldb-python

  handlers:

    - name: Install mysqldb-python

      raw: sudo yum install -y MySQL-python

[Dick Davies]

On 15 April 2014 09:24, Joachim Friberg <fetal...@gmail.com> wrote:

> For example I want to do a yum install mysql on a server, but this server
> does not have python-simplejson and/or other packages that is neccesary for
> Ansible.

In this specific case you'd just assert the python-simplejson package
exists right?
If it's already installed then nothing happens, and you'll be able to
skip on to the
other tasks.

If of course you're in a catch-22 situation (can't run ansible to set
up ansible pre-requisites),
then you'll need to seed your base image with what's required.

For example, my kickstarts bring up a machine with

* SSHd enabled and tcp/22 inbound permitted on the local firewall
* an 'ansible' account with a pre-defined list of SSH keys in its
authorised_keys file
* passwordless sudo configured for that account

Everything else is managed by Ansible.

This general approach also applies to CM with puppet, chef, etc.
(which typically
have much more requirements).

[Joachim Friberg]

Hmm -

I have fixed it with a when statement and then notify a handler that in turns install and notifies yet another handler.

Thou this solution does not look nice and I would really like to not relay on any other managementsystem other then Ansible.

My sollution to problem looks like this atm:

- name: something

  <do something>

  register: something

  ignore_errors: True

- name: simplejson

  raw: "yum -y install python-simplejson"

  when: something|failed

  notify:

    - somethingAgain

handlers:

  - name: somethingAgain

    <some action again>

...

  

The above one works kinda but is not the best looking.

Preffered would be similar to:

- name: something

  <do something>

  register: something

  notify_when: something|failed

    - simplejson

handlers:

  - name: simplejson

    raw: "yum -y install python-simplejson"

Does anyone know if something like this might be implemented in the near future or if anyone can point me to where I can suggest a "patch" :)

[Christian Rusa]

To be honest, I would also be interested in a solution to this.

Of course all the machines, that I install myself (preseed, kickstart,
...) meet the requirements for ansible.

For already existing machines which should be managed by us, the
requirements are somewhere in the middle of met or unmet.

To my knowledge python-simplejson (required on Python 2.4 boxes) can
only be installed using the raw module and not with the apt or yum module.
Therefore this is a task which I'd not like to be executed on every run.

Maybe the first task in the list could be an ansible ping and if it
fails do some brute-force raw commands.
....
And as writing this I answered my question :-)

My prototype looks like this:

- hosts: all
user: root
tasks:
- name: ping
ping:
register: result
- name: conditional task
raw: here_your_command
when: result|failed


Cheers
Christian

--
toscom - the open source company

Christian Rusa
Breiteneckergasse 32 1230 Wien
Mobil: 0699 10205595 Fax: 01 9249633
www.toscom.at christi...@toscom.at

[Michael DeHaan]

You are definitely overcomplicating it.

There's no reason to need the register really. 

- shell: yum -y install python-simplejson

Yum naturally is smart enough to not do anything if the package is already installed, so it takes care of the "idempotence" (I kinda still hate the over-complexity of that word, but it's a word) for you.

--
You received this message because you are subscribed to the Google Groups "Ansible Project" group.
To unsubscribe from this group and stop receiving emails from it, send an email to ansible-project+unsubscribe@googlegroups.com.
To post to this group, send email to ansible-project@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/534E16E8.1050305%40toscom.at.

For more options, visit https://groups.google.com/d/optout.

[Christian Rusa]

As we have to manage a mixed environment, we do have different packagemanagers.
So I often use when clauses like this
when: ansible_pkg_mgr == "apt"
I really like facts to be available in my playbooks.

So my goal is/was to avoid running raw yum commands against a debian or apt against Red Hat in our global site playbook.

A other thing I want to avoid is having a complicated documentation about which playbook to run against a server.
I am dreaming of a one-size-fits-all playbook :-)

Will the shell module work if the install of python-simplejson is required?
At least for the install of python (Minimal debian does not have it) I need to go for raw.

To unsubscribe from this group and stop receiving emails from it, send an email to ansible-proje...@googlegroups.com.
To post to this group, send email to ansible...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/534E16E8.1050305%40toscom.at.

For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "Ansible Project" group.

To unsubscribe from this group and stop receiving emails from it, send an email to ansible-proje...@googlegroups.com.
To post to this group, send email to ansible...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/CA%2BnsWgzxqTe_VgyjAXpz81FVzBfTbrfAjUyCKFZtZPYo0jfjKA%40mail.gmail.com.

For more options, visit https://groups.google.com/d/optout.

[Brian Coca]

- shell: yum install python-simplejson

  ignore_errors: true

  changed_when: False

ugly but should work

--
Brian Coca
Stultorum infinitus est numerus
0110000101110010011001010110111000100111011101000010000001111001011011110111010100100000011100110110110101100001011100100111010000100001

Pedo mellon a minno

[Michael DeHaan]

This is also a bit weird looking, but you could abuse the "removes" parameter to the shell command, which does not run a command when a binary does not exist.

The downside is this makes your playbook look weirder.

- shell: yum install python-simplejson removes=/usr/bin/yum

referenced here:  http://docs.ansible.com/shell_module.html

Generally this is done to prevent running installers a second time, and will not remove the indicated file.

Another solution is usually to have the kickstart or base image slightly prepped in the case of those older OSes, but we definitely don't require it.

--

You received this message because you are subscribed to the Google Groups "Ansible Project" group.
To unsubscribe from this group and stop receiving emails from it, send an email to ansible-proje...@googlegroups.com.
To post to this group, send email to ansible...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/CADn%2BHsw8CX0HLkZqzixhqgtS58TX-S3L%3DpTRcUaswNaEyGdnMA%40mail.gmail.com.