I have an ansible playbook, which has a variable defined in it like this:
- hosts: dev-web
become: yes
vars:
- web_dir: /opt/abc/example.com/xyz
i want the string inside the variable "/opt/abc/example.com/xyz" dynamically get from the host_var file in host_vars/dev-web.
host_var file looks like this:
vhosts:
dev1:
name: 'example.com'
dev2:
name: 'xyz.com'
Expected outcome dev1 is:
vars:
web_dir: /opt/abc/"{{ vhosts.dev1.name }}"/xyz
should reflect to
web_dir: /opt/abc/example.com/xyz
and for dev2:
vars:
web_dir: /opt/abc/"{{ vhosts.dev2.name }}"/xyz
should reflect to
web_dir: /opt/abc/xyz.com/xyz
Any help would be appreciated.
You have to approach the problem from a different perspective:
In the playbook, the variable should be identical for all hosts, i.e. vhost.name, which will take a different value in every host.
In the host_vars/ directory, you should have a different file for each host.
File host_vars/dev1:
vhost:
name: dev1
File host_vars/dev2:
vhost:
name: dev2
On another note, if possible, I'd rather reuse the real hostname using an automatically generated variable like: ansible_host or inventory_hostname.
Related
I'm starting to learn Ansible and for this I copy and paste examples from the documentation. For example this one
- name: Check that a page returns a status 200 and fail if the word AWESOME is not in the page contents
ansible.builtin.uri:
url: http://www.example.com
return_content: yes
register: this
failed_when: "'AWESOME' not in this.content"
which I've found in uri module documentation.
Every single time I do this, whatever the module I get:
ERROR! 'ansible.builtin.uri' is not a valid attribute for a Play
The error appears to have been in '/home/alfrerra/test2.yml': line 1, column 3, but may
be elsewhere in the file depending on the exact syntax problem.
The offending line appears to be:
- name: Check that a page returns a status 200 and fail if the word AWESOME is not in the page contents
^ here
I have only 2 playbooks that only ping successfully:
-
name: ping localhost
hosts: localhost
tasks:
- name: ping test
ping
and
---
- name: ping localhost
hosts: localhost
tasks:
- name: ping test
ping
So I adapted the example to match these 2 examples, but to no avail so far.
I'm sure it's nothing much but it's driving me crazy.
As already mentioned within the comments, the documentation are to show how to use certain parameter of certain modules within a single task. They are not mentioned to work in a copy and paste manner by itself or only.
You may have a look into the following minimal example playbook
---
- hosts: localhost
become: false
gather_facts: false
tasks:
- name: Check that a page returns a status 200 and fail if the word 'iana.org' is not in the page contents
uri:
url: http://www.example.com
return_content: yes
environment:
http_proxy: "localhost:3128"
https_proxy: "localhost:3128"
register: this
failed_when: "'iana.org' not in this.content"
- name: Show content
debug:
msg: "{{ this.content }}"
resulting into the output of the page content.
Please take note that the web page of the example domain is connected and delivers a valid result, but it does not contain the word AWESOME. To address this the string to lookup was changed to the page owner iana.org and to not let the task fail. Furthermore and since working behind a proxy it was necessary to address the proxy configuration and which you probably need to remove again.
Your first example is a single task and failing therefore with ERROR! ... not a valid attribute for a Play. Your second and
third examples are playbooks with a single task and therefore executing.
Documentation
Module format and documentation - EXAMPLES block
... show users how your module works with real-world examples in multi-line plain-text YAML format. The best examples are ready for the user to copy and paste into a playbook.
Ansible playbooks
failed_when must be a comparison or a boolean.
example :
- name: Check that a page returns AWESOME is not in the page contents
ansible.builtin.uri:
url: http://www.example.com
return_content: yes
register: this
failed_when: this.rc == 0;
It will execute the task only if the return value is equal to 0
I am trying to test something at home with the variables mechanism Ansible offers, which I am about to implement in one of my projects at work. So, been searching for a while now, but seems I can't get it working that easily, even with others` solutions here and there.
I will represent my project logic at work now, by demonstrating with my test directory & files structure at home. Here's the case, I have the following playbooks:
main.yaml
pl1.yaml
pl2.yaml
Contents of ./main.yaml:
- import_playbook: /home/martin/ansible/pl1.yaml
- import_playbook: /home/martin/ansible/pl2.yaml
Contents of ./pl1.yaml:
- name: Test playbook 1
hosts: localhost
tasks:
- name: Discovering the secret host
shell: cat /home/martin/secret
register: whichHostAd
- debug:
msg: "{{ whichHostAd.stdout }}"
- name: Discovering my hostname
shell: hostname
register: myHostnameAd
- set_fact:
whichHost: "{{ whichHostAd.stdout }}"
myHostname: "{{ myHostnameAd.stdout }}"
cacheable: yes
- name: Test playbook 1 part 2
hosts: "{{ hostvars['localhost']['ansible_facts']['whichHost'] }}"
tasks:
- name: Structuring info
shell: hostname
register: secretHostname
- name: Showing the secret hostname
debug:
msg: "{{ secretHostname.stdout }}"
Contents of ./pl2.yaml:
- name: Test Playbook 2
hosts: "{{ whichHost }}"
tasks:
- name: Finishing up
shell: echo "And here am i again.." && hostname
- name: Showing var myHostname
debug:
msg: "{{ myHostname.stdout }}"
The whole idea is to have a working variable on the go at the hosts field between the plays. How do we do that?
The playbook does not run at all if I won't define the whichHost variable as an extra arg, and that's ok, I can do it each time, but during the execution I would like to have that variable manageable and changeable. In the test case above, I want whichHost to be used everywhere across the plays/playbooks included in main.yaml, specifically to reflect the output of the first task in pl1.yaml (or the output of the whichHostAd.stdout variable), so I can determine the host I am about to target in pl2.yaml.
According to docs, I should be able to at least access it with hostvars (as in my playbook), but this is the output I get when I try the above example:
ERROR! The field 'hosts' has an invalid value, which includes an undefined variable. The error was: 'dict object' has no attribute 'whichHost'
The error appears to have been in '/home/martin/ansible/pl1.yaml': line 22, column 3, but may
be elsewhere in the file depending on the exact syntax problem.
The offending line appears to be:
- name: Test playbook 1 part 2
^ here
set_fact also does not seem to be very helpful. Any help will be appreciated!
Ok, I've actually figured it out pretty fast.
So, we definitely need to have a fact task, holding the actual data/output:
- hosts: localhost
tasks:
- name: Saving variable
set_fact:
whichHost: "{{ whichHostAd.stdout }}"
After that, when you want to invoke the var in other hosts and plays, we have to provide the host and the fact:
"{{ hostvars['localhost']['whichHost'] }}"
Like in my test above, but without ['ansible_facts']
I have a playbook which consists of two plays:
1: Create inventory file and variables file on localhost
2: Use the variables in commands on generated inventory
Example playbook:
---
- name: Generating inventory and variables
hosts: localhost
vars_files:
- variables.yml #variables file used for automating
tasks:
- name: Creating inventory template
template:
src: hosts.j2
dest: "./inventories/{{location}}/hosts"
mode: 0777
force: yes
ignore_errors: yes
run_once: true
- meta: refresh_inventory
- name: Creating predefined variables from a template
template:
src: predefined-vars.yml.j2
dest: "./variables/predefined-vars.yml"
- name: Setting vlan to network devices
remote_user: Ansible
hosts: all
vars_files:
- variables.yml #variables file used for automating.
- variables/predefined-vars.yml
tasks:
- name: configure Junos ROUTER for vlan
include_tasks: ./roles/juniper/tasks/add_vlan_rt.yml
when:
- inventory_hostname in groups['junos_routers']
- groups['junos_routers'] | length == 1
- location == inventory_name
This gives undefined variable error (for a variable created in the first play).
Is there a way to do this? I use this for generating variables like router_port_name and so on - the variables depend on location and dedicated server, which are defined in variables.yml
Any help is really appreciated.
Thanks
EDIT: However, I have noticed that this playbook:
---
- hosts: localhost
gather_facts: false
name: 1
vars_files:
- variables.yml
tasks:
- name: Creating predefined variables from a template
template:
src: predefined-vars.yml.j2
dest: "./variables/predefined-vars.yml"
- name: Generate hosts file
hosts: all
vars_files:
- variables.yml
- ./variables/predefined-vars.yml
tasks:
- name: test
debug: msg="{{ router_interface_name }}"
show the variables created in the first play.
The difference I see is that the first playbook reads all variable files (even predefined-vars.yml <- created at first play, used at the other) used in the playbook at the start of the first play (generating inventory and creating variable file) while the second playbook reads variables.yml in first play and only at the start of the second play reads the predefined-vars.yml .
Any Ideas how to make the first playbook behave the same way?
So I have found the solution to the problem, based on the documentation and suggestions from other people.
What I understood about the problem:
A playbook will read all the variables (of all plays) provided into the cache for later use, so if I include my predefined-vars.yml into vars_files, then after changing it in first play, the changes will not be used by later plays because they will use cache for that.
Thus I had to create another task in second play, which would read (load into cache) my newly generated file (for that play):
- name: Include predefined vars
include_vars: ./variables/predefined-vars.yml
run_once: true
Hope this helps you!
Still have no idea why second play shows the variables...
with Ansible I need to copy a script in different clients/hosts, then I need to modify a line in the script. The line depends of the client and is not the same each times.
Each hosts have the same name. Each clients name is different.
Something like that:
lineinfile: >
state=present
dest=/path/to/myscript
line="/personal line
when: {{ clients/hosts }} is {{ client/host }}
As you can see, I have no idea about the way to proceed.
It sounds like there are some clients that have some specific hosts associated to them, and the line in this script will vary based on the client.
In that case, you should use group vars. I've included a simplified example below.
Set up your hosts file like this:
[client1]
host1
host2
[client2]
host3
host4
Use group variables like this:
File group_vars/client1:
variable_script_line: echo "this is client 1"
File group_vars/client2:
variable_script_line: echo "this is client 2"
Create a template file named yourscript.sh.j2:
#!/bin/bash
# {{ ansible_managed }}
script line 1
script line 2
# below is the line that should be dynamic
{{ variable_script_line }}
And then use the template module like this:
---
- hosts: all
tasks:
- name: Deploy script to remote hosts
template:
src: /path/to/yourscript.sh.j2
dest: /path/to/location/yourscript.sh
mode: 0755
Note that the path to your source template will be different if you're using a [role][1].
Ultimately, when the play is run on client1 vs client2, the content of the template will be written differently based on the variable (see more about variable scopes).
I have defined a role dcn-rq2 and it has some variables defined in
~/dcn-rq2/defaults/main.yml file and i have written a playbook which includes this role at the top as shown below. my understanding is that all the vraiables defined in the role should automatically available to the playbook but it errors out.
//My top level YAML file for the playbook
- hosts: DCN-VSD
roles:
- dcn-rq2
tasks:
- debug: msg="{{test_var}}"
my dcn-rq2/defaults/main.yml
---
test_var: '12'
Defaults is something you use on roles. Playbooks use host_vars & groups_vars directories to include variables.
To add a global 'variable' shared across all your playbooks, place a 'all.yml' file in the group_vars directory.
More information can be found here:
http://docs.ansible.com/ansible/playbooks_variables.html#variable-precedence-where-should-i-put-a-variable
I just tried this and it works. The only difference I could see in your playbook is that the tasks section is not indented correctly. But I am assuming it changed when you copy/pasted it here.
---
- hosts: localhost
remote_user: root
roles:
- common
tasks:
- debug: msg="{{test_var}}"
Also you said
my understanding is that all the vraiables defined in the role should automatically available to the playbook
All the variables defined in the role will be available to the play you associate the role with in your playbook. In your case the only play in your playbook. So this should still work.