I'm trying to create a job role in Ansible to run yum install/update of packages, which will be provided by a 3rd party system as a .yml file to vars directory in a role with following convention: server01.yml, server02.yml, serverX.yml with variable in form packageList_serverNumber: 'list of packages'.
This variable will be read using a task:
- name: server update packages from host_vars
yum:
name: "{{ install_pkgs }}"
state: latest
This should point to host_vars file for specific host:
install_pkgs: "{{ packageList_server01 }}"
As this task should only run when the variable is defined, I was trying to use when clause with variable which will point to packageList_serverNumber. When I hardcode it, like below it is working:
when: packageList_server01 is defined
Can you please advise how to make it dynamic?
I was trying with:
when: packageList_{{hostvars[inventory_hostname]}} is defined
But unfortunately this is not working.
Use lookup plugin vars. Run the command below to see the details
shell> ansible-doc -t lookup vars
Given the vars files
shell> cat roles/test4/vars/server01.yml
packageList_server01: [pkg1, pkg2, pkg3]
shell> cat roles/test4/vars/server02.yml
packageList_server02: [pkg4, pkg5, pkg6]
shell> cat roles/test4/vars/server03.yml
packageList_server03: [pkg7, pkg8, pkg9]
read the vars, declare the variable install_pkgs, and use it
shell> cat roles/test4/tasks/main.yml
- include_vars: "vars/{{ inventory_hostname }}.yml"
- set_fact:
install_pkgs: "{{ lookup('vars', 'packageList_' ~ inventory_hostname) }}"
- debug:
msg: "Install {{ install_pkgs }}"
For example the playbook
- hosts: server01,server02,server03
gather_facts: false
roles:
- test4
gives (abridged)
TASK [test4 : debug] ****
ok: [server01] =>
msg: Install ['pkg1', 'pkg2', 'pkg3']
ok: [server03] =>
msg: Install ['pkg7', 'pkg8', 'pkg9']
ok: [server02] =>
msg: Install ['pkg4', 'pkg5', 'pkg6']
Related
Is there a way to use the value of one Ansible variable as the name of another variable so I can extract a value from its list?
host_vars:
this:
does: walk
says: hi
that:
does: run
says: hello
On the CLI when I run the playbook, I add -e="thing=this".
In the playbook, I've tried all manner of things to expand the variable thing to its value this, then use this to extract the value of does in the host_vars file.
Using the variable name directly obviously works:
- name: Check what the thing does
debug:
msg: "{{ this['does'] }}"
But the following do not:
{{ thing['does'] }}
{{ {{ thing }}['does'] }}
Those, plus several other iterations I've tried all either throw an error or print out the literal string.
You need the vars lookup plugin to address variables indirectly. See
shell> ansible-doc -t lookup vars
For example,
- debug:
msg: "{{ lookup('vars', thing).does }}"
should give (abridged)
shell> ansible-playbook pb.yml -e "thing=this"
...
msg: walk
Example of a complete playbook for testing
- hosts: localhost
vars:
this:
does: walk
says: hi
that:
does: run
says: hello
tasks:
- debug:
msg: "{{ lookup('vars', thing).does }}"
You can simplify the code further by putting all declarations into the vars. For example, into the group_vars/all
shell> cat group_vars/all/thing.yml
this:
does: walk
says: hi
that:
does: run
says: hello
_thing: "{{ lookup('vars', thing) }}"
Then, the simplified playbook below gives the same results
- hosts: localhost
tasks:
- debug:
var: _thing.does
I am tasked with creating a playbook, where I perform the following operations:
Fetch information from a YAML file (the file contains details on VLANs)
Cycle through the YAML objects and verify which subnet contains the IP, then return the object
The object contains also a definition of the inventory_hostname where to run the Ansible playbook
At the moment, I have the following (snippet):
Playbook:
- name: "Playbook"
gather_facts: false
hosts: "localhost"
tasks:
- name: "add host"
add_host:
name: "{{ vlan_target }}"
- name: "debug"
debug:
msg: "{{ inventory_hostname }}"
The defaults file defines the target_host as an empty string "" and then it is evaluated within another role task, like so (snippet):
Role:
- set_fact:
vlan_object: "vlan | trim | from_json | first"
- name: "set facts based on IP address"
set_fact:
vlan_name: "{{ vlan_object.name }}"
vlan_target: "{{ vlan_object.target }}"
delegate_to: localhost
What I am trying to achieve is to change the hosts: variable so that I can use the right target, since the IP/VLAN should reside on a specific device.
I have tried to put the aforementioned task above the add_host, or even putting in the same playbook, like so:
- name: "Set_variables"
hosts: "localhost"
tasks:
- name: "Set target host"
import_role:
name: test
tasks_from: target_selector
- name: "Playbook"
gather_facts: false
hosts: "localhost"
Adding a debug clause to the above playbook sets the right target, but it is not re-used below, making me think that the variable is not set globally, but within that run.
I am looking for a way to set the target, based on a variable that I am passing to the playbook.
Does anyone have any experience with this?
Global facts are not a thing, at best you can assign a fact to all hosts in the play, but since you are looking to use the said fact to add an host, this won't be a solution for your use case.
You can access facts of another hosts via the hostvars special variable, though. It is a dictionary where the keys are the names of the hosts.
The usage of the role is not relevant to your issue at hand, so, in the demonstration below, let's put this aside.
Given the playbook:
- hosts: localhost
gather_facts: no
tasks:
- set_fact:
## fake object, since we don't have the structure of your JSON
vlan_object:
name: foo
target: bar
- set_fact:
vlan_name: "{{ vlan_object.name }}"
vlan_target: "{{ vlan_object.target }}"
run_once: true
- add_host:
name: "{{ vlan_target }}"
- hosts: "{{ hostvars.localhost.vlan_target }}"
gather_facts: no
tasks:
- debug:
var: ansible_play_hosts
This would yield
PLAY [localhost] *************************************************************
TASK [set_fact] **************************************************************
ok: [localhost]
TASK [set_fact] **************************************************************
ok: [localhost]
TASK [add_host] **************************************************************
changed: [localhost]
PLAY [bar] *******************************************************************
TASK [debug] *****************************************************************
ok: [bar] =>
ansible_play_hosts:
- bar
ansible version: 2.9
Hi.
How can I specify the hosts when I import a playbook with import_playbook?
My code (/project/first_pb.yml)
- import_playbook: /test/pb0.yml
hosts: atlanta
Q: "A method to pass specific family hosts to the imported playbook?"
A: There is no difference between a playbook imported or not. For example,
shell> cat pb-A.yml
- hosts: "{{ my_hosts|default('localhost') }}"
tasks:
- debug:
var: inventory_hostname
shell> ansible-playbook pb-A.yml -e my_hosts=host1
...
inventory_hostname: host1
shell> cat pb-B.yml
- import_playbook: pb-A.yml
shell> ansible-playbook pb-B.yml -e my_hosts=host1
...
inventory_hostname: host1
There are many options on how to pass specific hosts and groups to a playbook. For example, see:
Patterns: targeting hosts and groups
add_host module – Add a host and group to the ansible-playbook in-memory inventory
Inventory plugins (e.g. constructed)
I can filter play plabooks with "when: " condition, for example:
- import_playbook: /test/pb0.yml
when: hostname != host1a*
- import_playbook: /test/pb0.yml
when: '"north" not in hostname'
- import_playbook: /test/pb0.yml
when: '"west" in hostname'
My question is somehow similar to the one posted here, but that doesn't quite answer it.
In my case I have an array containing multiple vars: entries, which I loop over when calling a certain role. The following examples shows the idea:
some_vars_file.yml:
redis_config:
- vars:
redis_version: 6.0.6
redis_port: 6379
redis_bind: 127.0.0.1
redis_databases: 1
- vars:
redis_version: 6.0.6
redis_port: 6380
redis_bind: 127.0.0.1
redis_databases: 1
playbook.yml:
...
- name: Install and setup redis
include_role:
name: davidwittman.redis
with_dict: "{{ dictionary }}"
loop: "{{ redis_config }}"
loop_control:
loop_var: dictionary
...
As far as I understand, this should just set the dictionary beginning with the vars node on every iteration, but it somehow doesn't. Is there any chance to get something like this to work, or do I really have to redefine all properties at the role call, populating them using with_items?
Given the role
shell> cat roles/davidwittman_redis/tasks/main.yml
- debug:
var: dictionary
Remove with_dict. The playbook
shell> cat playbook.yml
- hosts: localhost
vars_files:
- some_vars_file.yml
tasks:
- name: Install and setup redis
include_role:
name: davidwittman_redis
loop: "{{ redis_config }}"
loop_control:
loop_var: dictionary
gives
shell> ansible-playbook playbook.yml
PLAY [localhost] **********************************************
TASK [Install and setup redis] ********************************
TASK [davidwittman_redis : debug] *****************************
ok: [localhost] =>
dictionary:
vars:
redis_bind: 127.0.0.1
redis_databases: 1
redis_port: 6379
redis_version: 6.0.6
TASK [davidwittman_redis : debug] ******************************
ok: [localhost] =>
dictionary:
vars:
redis_bind: 127.0.0.1
redis_databases: 1
redis_port: 6380
redis_version: 6.0.6
Q: "Might there be an issue related to the variable population on role call?"
A: Yes. It can. See Variable precedence. vars_files is precedence 14. Any higher precedence will override it. Decide how to structure the data and optionally use include_vars (precedence 18). For example
shell> cat playbook.yml
- hosts: localhost
tasks:
- include_vars: some_vars_file.yml
- name: Install and setup redis
include_role:
name: davidwittman_redis
loop: "{{ redis_config }}"
loop_control:
loop_var: dictionary
Ultimately, command line --extra-vars would override all previous settings
shell> ansible-playbook playbook.yml --extra-vars "#some_vars_file.yml"
Q: "Maybe it is not possible to set the vars section directly via an external dictionary?"
A: It is possible, of course. The example in this answer clearly proves it.
I have a playbook in the format below:
---
- hosts: myIP
tasks:
- name: Install a yum package in Ansible example
yum:
name: ThePackageIWantToInstall
state: present
where myIP and ThePackageIWantToInstall are variables.
When the job template runs, I would like the user in the extra variables popup to be able to go with:
myIP = 192.168.1.1
ThePackageIWantToInstall = nano
As the documentation doesn't provide an example of supplying a variable via a job template, is this possible?
Yes.
- name: Do The Thing
hosts: "{{ foo }}"
roles:
- "{{ role }}"
Need mustaches and quotes.
to run from popup
(I don't use this, but it was suggested as an edit, thanks...)
foo: value
I have achieved similar thing with add_hosts. Here iam not installing package but creating file with name passed from command line. Any number of hosts (separated by commas can be passed from command line).
# cat addhost2.yml
- hosts: localhost
gather_facts: no
tasks:
- add_host:
name: "{{ item }}"
groups: hosts_from_commandline
with_items: "{{ new_hosts_passed.split(',') }}"
- hosts: hosts_from_commandline
tasks:
- name: Ansible create file with name passed from commandline
file:
path: "/tmp/{{ filename_from_commandline }}"
state: touch
# ansible-playbook -i hosts addhost2.yml --extra-vars='new_hosts_passed=192.168.3.104,192.168.3.113 filename_from_commandline=lathamdkv'
Hope this helps