How to get the installed yum packages with Ansible?
I can easily get it through using shell commands which is not idempotent
You can't really talk about idempotence, when you are querying the current state of a machine.
"Idempontent" means that the task will ensure the machine is in the desired state no matter how many times you run a certain task.
When you query current state, you don't describe the desired state. No matter what you do, what method you use, the term "idempotent" is just not applicable.
Regarding your example, which does not give you results - you have repeated twice the same argument list
and the task should fail (it doesn't, which looks like an Ansible quirk).
To get a list of installed packages, you should use:
- name: yum_command
yum:
list=installed
register: yum_packages
- debug:
var: yum_packages
It saves a list of dictionaries describing each package to a variable yum_packages
.
You can then use a JSON Query Filter to get a single package (tar
):
- debug: var=item
with_items: "{{yum_packages|json_query(jsonquery)}}"
vars:
jsonquery: "results[?name=='tar']"
to get a result like this:
"item": {
"arch": "x86_64",
"epoch": "2",
"name": "tar",
"nevra": "2:tar-1.26-31.el7.x86_64",
"release": "31.el7",
"repo": "installed",
"version": "1.26",
"yumstate": "installed"
}
Or only its version:
- debug: var=item
with_items: "{{yum_packages|json_query(jsonquery)}}"
vars:
jsonquery: "results[?name=='tar'].version"
"item": "1.26"
Since Ansible 2.5, you can also use the package_facts
module: it will gather the list of installed packages as Ansible facts.
Example from the docs:
- name: get the rpm package facts
package_facts:
manager: rpm
- name: show them
debug: var=ansible_facts.packages