This has to do with the way that new facts are returned from ansible
modules. Anytime a task is run, the module that is run by that task
has an opportunity to return new facts in an _ansible_facts entry.
This is usually a mapping of names to values that were determined
during the module's run. Ansible on the controlling machine reads the
data in _ansible_facts and adds the new facts to the global facts
dictionary that is available to subsequent tasks. Ansible does not
provide any automatic namespacing for the facts returned by tasks.
That means that if two tasks return dicts that use some of the same
keys in _ansible_facts then the values from the latest task to be run
will overwrite the earlier ones.
So to take three examples we have:
tasks:
- docker: name="cluster-data" hostname="{{ data_hostname }}"
image="lgueye/cluster-data" state=present
- docker: name="cluster-data" hostname="{{ index_hostname }}"
image="lgueye/cluster-data" state=present
In this example, we have two tasks calling the same module to do the
same thing to different hostnames. The module is almost certainly
going to return the same _ansible_facts dictionary entries for both
calls which means only the latest one will be seen by subsequent
tasks.
tasks:
- docker: image=df02bd73464a name=somename_{{item}}
with_sequence: count={{ start_containers_count }}
In this example, we are looping start_containers_count times and
invoking the docker module each time with a slightly different name
parameter. So even though it's not as apparent, it's doing the same
thing as the above example.
tasks:
- docker: image=df02bd73464a count={{ start_containers_count }}
Only in this example are we actually executing the docker module only
a single time. We're telling the module that it is responsible for
starting up start_countainr_count instances on its own. Since the
module has all the information in its one invocation to start all of
hte containers, it is able to return information about all of the
containers that it started in its one run to the ansible controller so
the facts are set so that you can see all of the ip and host
information.
Hope that explanation is helpful!
-Toshio
On Tue, Nov 18, 2014 at 3:41 PM, louis gueye <[email protected]> wrote:
> Hi Patrick,
>
> Actually i don't know if it has anything to do with the "with_sequences"
> clause. I have the following code
>
> docker: name="cluster-data" hostname="{{ data_hostname }}"
> image="lgueye/cluster-data" state=present
> .
> .
> .
> docker: name="cluster-index" hostname="{{ index_hostname }}"
> image="lgueye/cluster-index" state=present
>
> When I loop over the docker_containers dict, seeking for IP adresses, I only
> get one IP adress.
> I dumped the dict and It contains information only about the last running
> container.
>
> I'm just providing information, unfortunately I I'm totally unable to
> provide a fix right now. Sorry.
>
>
> Le mercredi 16 avril 2014 23:41:04 UTC+2, Patrick Galbraith a écrit :
>>
>> Hi all!
>>
>> I have what I think is a simple question. It pertains to what is
>> visible/available in the "docker_containers" dictionary when running a run
>> book.
>>
>> Ok, so, what’s throwing me off is whether to use one of the following:
>>
>> - name launch containers
>>
>> docker: image=df02bd73464a count={{ start_containers_count }}
>>
>> Or
>>
>> - name launch containers
>>
>> docker: image=df02bd73464a name=somename_{{item}}
>>
>> with_sequence: count={{ start_containers_count }}
>>
>> It is the first snippet that works for doing this next task:
>>
>> - name: print container info
>>
>> debug: msg="{{item['NetworkSettings']['IPAddress']}}"
>>
>> with_items: docker_containers
>>
>> Why? Because the latter results in “docker_containers” only having the
>> last container’s information (last container launched), whereas the former
>> gives me all of them.
>>
>>
>> It’s probably something really simple…
>
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