Problem with var within a playbook

[KSS]

Hi,

I'm having a problem with a particular variable. 

I'm hoping figuring out the problem below will help me understand the issue with a larger playbook.

# ansible --version

ansible 1.9.2

A simple playbook (I need the list of ip addresses as it is passed to an api in one request);

---

    - hosts: all

      gather_facts: true

      vars:

          ip: "{% for host in groups['all'] %}{{ hostvars[host]['ansible_default_ipv4']['address'] }}{% if not loop.last %},{% endif %}{% endfor %}"

      tasks:

      - name: Debug

        debug: msg="IPaddresses={{ ip }}"

        delegate_to: localhost

        run_once: true

        tags: first-play

    - hosts: all

      gather_facts: true

      vars:

          ip: "{% for host in groups['all'] %}{{ hostvars[host]['ansible_default_ipv4']['address'] }}{% if not loop.last %},{% endif %}{% endfor %}"

      tasks:

      - name: Debug 2

        debug: msg="2nd list of IPaddresses={{ ip }}"

        delegate_to: localhost

        run_once: true

        tags: second-play

------------- End of playbook -------------------

When the above is run one task at a time (i.e using the tags) it works fine;

# ansible-playbook -i 'host1,host2' ./test-ipvar.yml --tags first-play

PLAY [all] ********************************************************************


GATHERING FACTS ***************************************************************
ok: [host1]
ok: [host2]


TASK: [Debug] *****************************************************************
ok: [host1 -> localhost] => {
    "msg": "IPaddresses=10.0.0.1,10.0.0.2"
}


PLAY RECAP ********************************************************************
host2               : ok=2    changed=0    unreachable=0    failed=0
host1                  : ok=2    changed=0    unreachable=0    failed=0

# ansible-playbook -i 'host1,host2' ./test-ipvar.yml --tags second-play

PLAY [all] ********************************************************************


GATHERING FACTS ***************************************************************
ok: [host1]
ok: [host2]

Enter code here...

TASK: [Debug 2] ***************************************************************
ok: [host1 -> localhost] => {
    "msg": "2nd list of IPaddresses=10.0.0.1,10.0.0.2"
}


PLAY RECAP ********************************************************************
host2               : ok=2    changed=0    unreachable=0    failed=0
host1                  : ok=2    changed=0    unreachable=0    failed=0

However, running the playbook, we get an error for the second play although that variable is clearly available before;

# ansible-playbook -i 'host1,host2' ./test-ipvar.ymlEnter code here...



PLAY [all] ********************************************************************


GATHERING FACTS ***************************************************************
ok: [host1]
ok: [host2]


TASK: [Debug] *****************************************************************
ok: [host1 -> localhost] => {
    "msg": "IPaddresses=10.0.0.1,10.0.0.2"
}


PLAY [all] ********************************************************************


GATHERING FACTS ***************************************************************
ok: [host1]
ok: [host2]


TASK: [Debug 2] ***************************************************************
fatal: [host1 -> localhost] => One or more undefined variables: 'dict' object has no attribute 'ansible_default_ipv4'


FATAL: all hosts have already failed -- aborting


PLAY RECAP ********************************************************************
           to retry, use: --limit @/root/test-ipvar.retry


host2               : ok=3    changed=0    unreachable=0    failed=1
host1                  : ok=3    changed=0    unreachable=0    failed=1

Even putting both tasks in the same play results in only the first play being successful.

Does anyone have any ideas why it behaves this way?

[KSS]

Looks like it's better to use set_fact here (well, that method works). It would still be good to understand why the above fails though

[KSS]

Strangely, if I use ;

 ip: "{% for host in play_hosts %}{{ hostvars[host]['ansible_default_ipv4']['address'] }}{% if not loop.last %},{% endif %}{% endfor %}"

This all works across both tasks (or both plays, if split it into two plays) whereas using "groups['all']" fails on the second task