'How can I get the installed YUM packages with Ansible?
I am trying to get all the installed YUM packages on an RHEL machine. I can easily get it through using shell commands which is not idempotent and would like to use the YUM command instead.
The shell command works fine:
- name: yum list packages
shell: yum list installed > build_server_info.config
But when I try to use the YUM command, it just executes, but it does not give any results:
- name: yum_command
action: yum list=${pkg} list=available
Solution 1:[1]
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"
Solution 2:[2]
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 CPU:
- name: get the rpm package facts
package_facts:
manager: rpm
- name: show them
debug: var=ansible_facts.packages
Solution 3:[3]
Well, the official Ansible documentation for the yum module
describes list as:
"Various (non-idempotent) commands for usage with /usr/bin/ansible and not playbooks."
so you're going to be out of luck with finding an idempotent list
invocation.
If you just want to suppress the changed
output, set the changed_when
parameter to False
.
(Also, having the duplicate list
parameter is suspicious.)
Solution 4:[4]
If your requirement is to check for only one package, and based on that you want to execute another task, you can use package_facts
module as
- name: install docker community edition in rhel8
hosts: localhost
connection: local
tasks:
- name: Gather the rpm package facts
package_facts:
manager: auto
- name: check if docker-ce is already installed
debug:
var: ansible_facts.packages['docker-ce']
- name: using command module to install docker-ce
command: yum install docker-ce --nobest -y
when: "'docker-ce' not in ansible_facts.packages"
register: install_res
- name: whether docker is installed now
debug:
var: install_res
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
Solution | Source |
---|---|
Solution 1 | |
Solution 2 | Peter Mortensen |
Solution 3 | Kyle |
Solution 4 | Peter Mortensen |