# Migrating from 1.1 to 1.2, problems replacing "only\_if" with "when" **URL:** \ **Category:** Ansible Project\ **Tags:** ubuntu\ **Created:** [July 16, 2013, 8:30am UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131 "2013-07-16T08:30:54Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Antonio\_Messina](https://avatars.discourse-cdn.com/v4/letter/a/9de053/32.png) [@Antonio\_Messina](https://forum.ansible.com/u/Antonio_Messina)\ **Post date:** [July 16, 2013, 8:30am UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/1 "2013-07-16T08:30:54Z")
Hi all, I am starting to migrate my playbooks from Ansible 1.1 to Ansible 1.2 and I am getting a few problems. To distinguish between CentOS and Ubuntu distributions, I used to set two variables, "is\_centos" and "is\_ubuntu" in the following way:     is\_ubuntu: "'${ansible\_distribution}' == 'Ubuntu'"     is\_centos: "'${ansible\_distribution}' == 'CentOS'" and then use the "only\_if" statement in my tasks, like:       - action: debug msg="This is a CentOS"       only\_if: $is\_centos     - action: debug msg="This is an Ubuntu machine"       only\_if: $is\_ubuntu and this worked as expected. Now I would like to use "when" instead of "only\_if", which is deprecated, but when I try the following:     - action: debug msg="This is a CentOS"       when: is\_centos     - action: debug msg="This is an Ubuntu machine"       when: is\_ubuntu it always execute both tasks. I've also tried to convert the "vars" section to a jinja2-like declaration:     is\_ubuntu: "{{ ansible\_distribution == 'Ubuntu' }}"     is\_centos: "{{ ansible\_distribution == 'CentOS' }}" but still it does not work as expected. This is the playbook I'm testing (on a Ubuntu machine): ---
**Author:** ![Antonio\_Messina](https://avatars.discourse-cdn.com/v4/letter/a/9de053/32.png) [@Antonio\_Messina](https://forum.ansible.com/u/Antonio_Messina)\ **Post date:** [July 16, 2013, 8:54am UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/2 "2013-07-16T08:54:39Z")
I think the problem is related to the fact that the value of "is\_ubuntu" becomes a \*string\* instead of a boolean. If I use as a conditional the following statement:     when: is\_ubuntu == 'True' it works. Also, if I set the variable explicitly as a YAML boolean:     vars:       is\_ubuntu: true       is\_centos: false it works, but I don't know how to set these variables with YAML booleans instead of strings using an expression... Also this does not work:     - action: set\_fact is\_ubuntu={{ ansible\_distribution == 'Ubuntu' }}     - action: set\_fact is\_centos={{ ansible\_distribution == 'CentOS' }} because "is\_ubuntu" and "is\_centos" still are evaluated as strings. .a. ---
**Author:** ![Antonio\_Messina](https://avatars.discourse-cdn.com/v4/letter/a/9de053/32.png) [@Antonio\_Messina](https://forum.ansible.com/u/Antonio_Messina)\ **Post date:** [July 16, 2013, 9:38am UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/3 "2013-07-16T09:38:38Z")
I don't know if this is related or not, but I've also found that "{{ variable }}" is treated differently from "${variable}". In one of my playbooks I have something like:     - include: common/tasks/iptables.yml trusted\_hosts=${groups.slurm\_clients} the iptables.yml file contains: - action: template dest={{ destfile }} src=common/templates/etc/iptables.d/rules.v4.j2 owner=root group=root mode=0644   tags: iptables and the template contains: {% for host in trusted\_hosts|sort %} -A INPUT -s {{ host }} -j ACCEPT {% endfor %} the resulting output is: -A INPUT -s compute001 -j ACCEPT -A INPUT -s compute002 -j ACCEPT but if I use {{groups.all}} instead of ${groups.all} the resulting output is: -A INPUT -s [ -j ACCEPT -A INPUT -s ' -j ACCEPT -A INPUT -s c -j ACCEPT -A INPUT -s o -j ACCEPT -A INPUT -s m -j ACCEPT -A INPUT -s p -j ACCEPT -A INPUT -s u -j ACCEPT -A INPUT -s t -j ACCEPT -A INPUT -s e -j ACCEPT -A INPUT -s 0 -j ACCEPT -A INPUT -s 0 -j ACCEPT -A INPUT -s 2 -j ACCEPT -A INPUT -s ' -j ACCEPT -A INPUT -s , -j ACCEPT -A INPUT -s -j ACCEPT -A INPUT -s ' -j ACCEPT -A INPUT -s c -j ACCEPT -A INPUT -s o -j ACCEPT -A INPUT -s m -j ACCEPT -A INPUT -s p -j ACCEPT -A INPUT -s u -j ACCEPT -A INPUT -s t -j ACCEPT -A INPUT -s e -j ACCEPT -A INPUT -s 0 -j ACCEPT -A INPUT -s 0 -j ACCEPT -A INPUT -s 1 -j ACCEPT -A INPUT -s ' -j ACCEPT -A INPUT -s ] -j ACCEPT exactly like the "trusted\_hosts" variable is treated as the string: "['compute001', 'compute002']" instead of a list of strings. .a. ---
**Author:** ![Michael\_DeHaan2](https://avatars.discourse-cdn.com/v4/letter/m/da6949/32.png) [@Michael\_DeHaan2](https://forum.ansible.com/u/Michael_DeHaan2)\ **Post date:** [July 16, 2013, 11:49am UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/4 "2013-07-16T11:49:46Z")
There’s already a ticket on this, I’ll have to find it. I strongly recommend looking into the “group\_by” module for mapping configurations based on OS’es though, as the output is much nicer to not see all the ‘skipped’ steps. groups.all is a list, you should walk over it in a loop. ---
**Author:** ![Antonio\_Messina1](https://avatars.discourse-cdn.com/v4/letter/a/5fc32e/32.png) [@Antonio\_Messina1](https://forum.ansible.com/u/Antonio_Messina1)\ **Post date:** [July 16, 2013, 3:35pm UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/5 "2013-07-16T15:35:05Z")
> There’s already a ticket on this, I’ll have to find it. Thank you! > I strongly recommend looking into the “group\_by” module for mapping configurations based on OS’es though, as the output is much nicer to not see all the ‘skipped’ steps. I see your point, but I don’t really care about the output, and I want to migrate the syntax without changing too much. If I would have to use “group\_by” for this kind of things I will have to re-structure all my playbooks ☹ > groups.all is a list, you should walk over it in a loop. I am not sure I understand your answer. I _am_ looping, but inside a template. I want to pass a list of hosts to a template, so that it will produce a line for each item of the list, this is something I can’t do using “with\_items”. The problem is that when I use {{ groups.all }}, in the template I get a string instead of a list, so iterating over it means iterating over all the characters of the string representation of the list… .a. ---
**Author:** ![Michael\_DeHaan2](https://avatars.discourse-cdn.com/v4/letter/m/da6949/32.png) [@Michael\_DeHaan2](https://forum.ansible.com/u/Michael_DeHaan2)\ **Post date:** [July 16, 2013, 5:27pm UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/6 "2013-07-16T17:27:01Z")
{% for x in groups[‘all’] %} {{ x }} {% endfor %} ---
**Author:** ![Antonio\_Messina](https://avatars.discourse-cdn.com/v4/letter/a/9de053/32.png) [@Antonio\_Messina](https://forum.ansible.com/u/Antonio_Messina)\ **Post date:** [July 16, 2013, 5:33pm UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/7 "2013-07-16T17:33:37Z")
> {% for x in groups['all'] %} >    {{ x }} > {% endfor %} I don't want it hardcoded in the template! As I wrote before, this is what I want to have:     - include: common/tasks/iptables.yml trusted\_hosts=${groups.slurm\_clients} where "trusted\_hosts" might change (in this example is "slurm\_clients", but could be just a list of hosts). the iptables.yml file contains: - action: template dest={{ destfile }} src=common/templates/etc/iptables.d/rules.v4.j2 owner=root group=root mode=0644   tags: iptables and the template contains: {% for host in trusted\_hosts|sort %} -A INPUT -s {{ host }} -j ACCEPT {% endfor %} If I write "trusted\_hosts={{groups.slurm\_clients}}" the template will receive a \*string\*, while if I write "trusted\_hosts=${groups.slurm\_clients}" it receives a list, as expected. Is this a bug or is the expected behavior? Is there a difference between "${variable}" and "{{variable}}" or there should not? .a. ---
**Author:** ![Michael\_DeHaan2](https://avatars.discourse-cdn.com/v4/letter/m/da6949/32.png) [@Michael\_DeHaan2](https://forum.ansible.com/u/Michael_DeHaan2)\ **Post date:** [July 16, 2013, 5:45pm UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/8 "2013-07-16T17:45:23Z")
So we were intending to deprecate ${foo} but effectively it still works nicely for pass by reference, so I suspect it will be repurposed for such. In your case, it’s a matter of passing it in a dictionary rather than a string, since it can’t tell what you want the way it’s dereferenced above. However this works today: - include: common/tasks/main/iptables.yml vars: trusted\_hosts: ${groups.all} Though I really want to unify this syntax so it plays more nicely with roles, also, i.e. - include: … trusted\_hosts: ${groups.all} Aka shorthand - { include: filename.yml, trusted\_hosts: ${groups.all} } The two latter forms are not implemented, but the first works for me today. Hope this helps! ---
**Author:** ![Antonio\_Messina](https://avatars.discourse-cdn.com/v4/letter/a/9de053/32.png) [@Antonio\_Messina](https://forum.ansible.com/u/Antonio_Messina)\ **Post date:** [July 17, 2013, 9:14am UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/9 "2013-07-17T09:14:58Z")
Thank you, this clarifies it. I think that for now I will continue to use '${}' then, since it's not going to be deprecated. .a. ---
**Author:** ![Michael\_DeHaan2](https://avatars.discourse-cdn.com/v4/letter/m/da6949/32.png) [@Michael\_DeHaan2](https://forum.ansible.com/u/Michael_DeHaan2)\ **Post date:** [July 17, 2013, 11:19am UTC](https://forum.ansible.com/t/migrating-from-1-1-to-1-2-problems-replacing-only-if-with-when/13131/10 "2013-07-17T11:19:51Z")
It may be at some point, but in the case of passing a variable reference, it’s currently useful.