# special dict hostvars **URL:** \ **Category:** Ansible Project\ **Created:** [February 18, 2015, 6:45pm UTC](https://forum.ansible.com/t/special-dict-hostvars/17556 "2015-02-18T18:45:56Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Serge\_van\_Ginderacht](https://avatars.discourse-cdn.com/v4/letter/s/b782af/32.png) [@Serge\_van\_Ginderacht](https://forum.ansible.com/u/Serge_van_Ginderacht)\ **Post date:** [February 18, 2015, 6:45pm UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/1 "2015-02-18T18:45:56Z")
Hi, We’re used to do things like hostvars[inventory\_hostname].somevar Now, I wanted to debug someting and did ansible all -m debug -a var=hostvars I expected this to return something like { ‘hostvars’: ‘host1’: ‘somevar’ : somevalue … ‘host2’: … … } Instead I got host1: { ‘somevar’ : somevalue … } host2: … Another example is at [https://p.6core.net/p/RCJAYyK1gzBuEcwZa8Tgx4S5](https://p.6core.net/p/RCJAYyK1gzBuEcwZa8Tgx4S5) Now i know ‘hostvars’ is a special kind of object (some kind of dict that caches things), but I’m confused on this difference, and have no explanation for it. Serge ---
**Author:** ![Brian\_Coca](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@Brian\_Coca](https://forum.ansible.com/u/Brian_Coca)\ **Post date:** [February 18, 2015, 7:07pm UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/2 "2015-02-18T19:07:47Z")
In code the difference is mostly that hostvars is a 'cache' object that internally implements most (but not all, it seems) the methods of a dictionary. The default cache is an actual in memory dictionary but the object still acts as an intermediary. There is probably a way to make it behave exactly the same in this case, but I would need to look into it deeper. ---
**Author:** ![Serge\_van\_Ginderacht](https://avatars.discourse-cdn.com/v4/letter/s/b782af/32.png) [@Serge\_van\_Ginderacht](https://forum.ansible.com/u/Serge_van_Ginderacht)\ **Post date:** [February 18, 2015, 7:33pm UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/3 "2015-02-18T19:33:15Z")
> In code the difference is mostly that hostvars is a 'cache' object > that internally implements most (but not all, it seems) the methods of > a dictionary. The default cache is an actual in memory dictionary but > the object still acts as an intermediary. ​Yes, that's what special about hostvars in the code. But as to what the 'hostvars' var is in ansible playbooks, we're still missing ​the difference between two things in your assertion here. It sounds like something weird though. There is probably a way to make it behave exactly the same in this > case, but I would need to look into it deeper. ​Given time I'll try to have a look myself. Perhaps this is part a thing for -devel, as it seems to me BTW, another example of how this is weird, just run these commands from an empty dir: serge@cyberlab:~/tmp$ ansible all -i localhost, -c local -m debug -a > var=hostvars[inventory\_hostname] localhost | success \>\> { >     "hostvars[inventory\_hostname]": { >         "group\_names": , >         "inventory\_hostname": "localhost", >         "inventory\_hostname\_short": "localhost" >     } > } > > serge@cyberlab:~/tmp$ ansible all -i localhost, -c local -m debug -a > var=hostvars > localhost | success \>\> { >     "hostvars": { >         "group\_names": , >         "inventory\_hostname": "localhost", >         "inventory\_hostname\_short": "localhost" >     } > } Thanks,    Serge ---
**Author:** ![jpmens.dns](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@jpmens.dns](https://forum.ansible.com/u/jpmens.dns)\ **Post date:** [February 18, 2015, 8:20pm UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/4 "2015-02-18T20:20:25Z")
The question then is, how do I loop over the hostvars for hosts in a template? The original question popped up today, because I was trying something which used to work: {% for host, v in hostvars.iteritems() %} {{ host }} == {{ v[‘ansible\_distribution\_version’] }} … etc. {% endfor %} I _know_ this worked for hosts because I copied it from an old presentation I did. Nowadays (1.8.2) it no longer works: because of the extra keys in hostvars. Regards, -JP ---
**Author:** ![Brian\_Coca](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@Brian\_Coca](https://forum.ansible.com/u/Brian_Coca)\ **Post date:** [February 18, 2015, 10:25pm UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/5 "2015-02-18T22:25:42Z")
i have this from an old template: {% for host in groups['all'] %} {% for k in hostvars[host] %} .... ---
**Author:** ![Jan-Piet\_Mens](https://avatars.discourse-cdn.com/v4/letter/j/34f0e0/32.png) [@Jan-Piet\_Mens](https://forum.ansible.com/u/Jan-Piet_Mens)\ **Post date:** [February 19, 2015, 7:48am UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/6 "2015-02-19T07:48:13Z")
Thanks Brian, but that also no longer works, at least not for me. I've put up an example here: [https://p.6core.net/p/yIT8nVBZXlOJyZERHoxA3Rmz](https://p.6core.net/p/yIT8nVBZXlOJyZERHoxA3Rmz) Am I misunderstanding what hostvars \_should\_ contain? Regards,         -JP ---
**Author:** ![Serge\_van\_Ginderacht](https://avatars.discourse-cdn.com/v4/letter/s/b782af/32.png) [@Serge\_van\_Ginderacht](https://forum.ansible.com/u/Serge_van_Ginderacht)\ **Post date:** [February 19, 2015, 8:28am UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/7 "2015-02-19T08:28:53Z")
AFAIK, hostvars should be a dict of dicts, where the keys are the inventory\_hostnames. The fact that host variables are put directly in hostvars, is a bug, I think.​ Looking at the code, I think there was confusion between 'hostvars' as we know to use it in playbooks and templates, which is a variable in the 'inject', and hostvars, a host specific vari containg the hosts' variables, and used in the Runner() object. This might fix it: diff --git a/lib/ansible/runner/\_\_init\_\_.py b/lib/ansible/runner/\_\_init\_\_.py index 79a167c..501dc41 100644 --- a/lib/ansible/runner/\_\_init\_\_.py +++ b/lib/ansible/runner/\_\_init\_\_.py @@ -684,7 +684,8 @@ class Runner(object):          # and we save the HostVars in the injected dictionary so they          # may be referenced from playbooks/templates - inject['hostvars'] = hostvars + inject['hostvars'] = {} + inject['hostvars'][host] = hostvars          host\_connection = inject.get('ansible\_connection', self.transport)          if host\_connection in ['paramiko', 'ssh', 'accelerate']: You can check out my branch here to test that:   [https://github.com/srvg/ansible/tree/fix\_inject\_hostvars](https://github.com/srvg/ansible/tree/fix_inject_hostvars) Serge ---
**Author:** ![Jan-Piet\_Mens](https://avatars.discourse-cdn.com/v4/letter/j/34f0e0/32.png) [@Jan-Piet\_Mens](https://forum.ansible.com/u/Jan-Piet_Mens)\ **Post date:** [February 19, 2015, 9:29am UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/8 "2015-02-19T09:29:02Z")
> You can check out my branch here to test that: As mentioned to you privately, this reports KeyError '127.0.0.1' on a template which contains         {% for host in hostvars %}         {{ host }}         {% endfor %} Regards,         -JP ---
**Author:** ![Brian\_Coca](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@Brian\_Coca](https://forum.ansible.com/u/Brian_Coca)\ **Post date:** [February 19, 2015, 1:10pm UTC](https://forum.ansible.com/t/special-dict-hostvars/17556/9 "2015-02-19T13:10:54Z")
I just tested this and it seems to work fine in current devel: ----dump.j2 {% for host in groups['all'] %} {{host}}: {% for k in hostvars[host] %}     {{k}}: {{ hostvars[host][k]}} {% endfor %} {% endfor %} --- play.yml - hosts: localhost   tasks:     - template: src=templates/dump.j2 dest=/tmp/dump.txt       connection: local