In ansible, I do some code on a remote machine, and then I want to use the result from the vars_prompt again on a different host. I've searched around, and the docs make it sound like i should use {{ hostvars.local_server_name_in_vagrant_group.local_username }}, using my example below to set the context. However, it says that the index from the dictionary doesn't exist when referencing hostvars. Instead, as shown below, I simply do a vars_prompt twice. Gross! Any tips?
BTW, there's also discussion on whether or not using vars_prompt is a great idea. I have confirmed that for my usage, indeed, I do want to use vars_prompt. Thanks!
- hosts: vagrant
vars_prompt:
local_username: "enter your desired local username"
... remote task activity using local_username...
- hosts: localhost
connection: local
vars_prompt:
local_username: "enter your desired local username, again (please)
... host task activity, also using local_username ...
As I said in the comment to the question :
You can use set_facts to register your variable as a fact of the current host and access it from a different one. I do not think standard variables are stored after the role/tasks.
Here is an example :
- name: First
connection: local
hosts: host1
tasks:
- name: register real root user to localhost facts
set_fact: fact_for_host1="1"
- name: Second
connection: local
hosts: host2
tasks:
- debug: msg="{{ hostvars['host1']['fact_for_host1'] }}"
Note that the connection: local is present only for local tests purpose.
Related
I want to parameterize (use a variable) for remote_user in ansible.
This is the first part from the playbook:
- hosts: xxx
remote_user: "centos"
become: true
I will replace it with
- hosts: wazuh
remote_user: "{{ new_user }}"
become: true
But what is a good place to store the value of this variable? It seems group_vars/all mostly contain variables which are more app/env specific than ansible specific. Or should I put it in inventories/hosts as a var? What is the recommended location to store it?
You should actually store it in your inventory as ansible_user either for the all group (for all host), a specific group or a specific host. You can keep a remote_user in your play which will be used in case the ansible_user is not defined for some hosts in your inventory. If you remove it, you local user on the controller will be the default, unless you use the -u flag on the command line.
You can find a good explanation of the difference between ansible_user and remote_user and how the overide works in the documentation on variable precedence
Using a var as you wrote it in your above example can actually work. But since it must be expanded before the play actually starts and any action is taken on any host, the only place you can "store" it is in an extra_var on the command line.
To be a little more practical, here is what I suggest from your above example:
inventories/dev/hosts.yml
---
wazuh:
hosts:
host_a.wazuh.tld:
host.b.wazuh.tld:
inventories/dev/group_vars/wazuh.yml
---
# Vars for the wazuh group
ansible_user: centos
plabook.yml
---
- hosts: wazuh
tasks:
- name: Proove we connected with the given user
cmd: whoami
register: whoami_result
- name: Show actual result
debug:
var: whoami_result.stdout
Launching the playbook:
ansible-playbook -i inventories/dev playbook.yml
Is there a special variable where ansible master machine hostname is stored (not hosts where action are running : ansible_host inventory_hostname ) ?
I want to get my local hostname while running a playbook against hosts.
for example i have installed my ansible on : machine1 and i'm running it against machine_dev , how to get machine1 in a special variable without a localhost hostname shell command ?
The hostname is stored in the fact ansible_hostname. You need to gather facts for this.
All gathered hosts facts are available through the hostvars hashmap
If you gather facts for localhost in your very first play, the local hostname will be available anywhere else in hostvars.localhost.ansible_hostname
Here is a quick demo of how you can use this.
---
- hosts: localhost
- hosts: all
tasks:
- name: show localhost hostname for each current host in the play loop
debug:
msg: "{{ hostvars.localhost.ansible_hostname }}"
Running Ansible 2.9.3
Working in a large environment with hosts coming and going on a daily basis, I need to use wildcard hostnames in a host group: ie:
[excluded_hosts]
host01
host02
host03
[everyone]
host*
in my playbook I have
name: "Test working with host groups"
hosts: everyone,!excluded_hosts
connection: local
tasks:
The problem is, the task is running on hosts in the excluded group.
If I specifically list one of the excluded hosts in the everyone group, that host then gets properly excluded.
So Ansible isn't working as one might assume it would.
What's the best way to get this to work?
I tried:
hosts: "{{ ansible_hostname }}",!excluded_hosts
but it errored as invalid yaml syntax.
requirements: I can not specifically list each host, they come and go too frequently.
The playbooks are going to be automatically copied down to each host and the execution started afterwards, therefore I need to use the same ansible command line on all hosts.
I was able to come up with a solution to my problem:
---
- name: "Add host name to thishost group"
hosts: localhost
connection: local
tasks:
- name: "add host"
ini_file:
path: /opt/ansible/etc/hosts
section: thishost
option: "{{ ansible_hostname }}"
allow_no_value: yes
- meta: refresh_inventory
- name: "Do tasks on all except excluded_hosts"
hosts: thishost,!excluded_hosts
connection: local
tasks:
What this does is it adds the host's name to a group called "thishost" when the playbook runs. Then it refreshs the inventory file and runs the next play.
This avoids a having to constantly update the inventory with thousands of hosts, and avoids the use of wildcards and ranges.
Blaster,
Have you tried assigning hosts by IP address yet?
You can use wildcard patterns ... IP addresses, as long as the hosts are named in your inventory by ... IP address:
192.0.\*
\*.example.com
\*.com**
https://docs.ansible.com/ansible/latest/user_guide/intro_patterns.html
I am trying to use ansible to modify the hostnames of a dozen newly created Virtual Machines, and I am failing to understand how to loop correctly.
Here is the playbook I've written:
---
- hosts: k8s_kvm_vms
tasks:
- name: "update hostnames"
hostname:
name: "{{ item }}"
with_items:
- centos01
- centos02
...
The result is that it updates each host with each hostname. So if I have 12 machines, each hostname would be "centos12" at the end of the playbook.
I expect this behavior to essentially produce the same result as:
num=0
for ip in ${list_of_ips[*]}; do
ssh $ip hostnamectl set-hostname centos${num}
num=$((num+1))
done
If I were to write it myself in bash
The answer on this page leads me to believe I would have to include all of the IP addresses in my playbook. In my opinion, the advantage of scripting would be that I could have the same hostnames even if their IP changes (I just have to copy the ip addresses into /etc/ansible/hosts) which I could reuse with other playbooks. I have read the ansible page on the hostname module, but their example leads me to believe I would, instead of using a loop, have to define a task for each individual IP address. If this is the case, why use ansible over a bash script?
ansible hostname module
You can create a new variable for each of the servers in the inventory like
[k8s_kvm_vms]
server1 new_hostname=centos1
server2 new_hostname=centos2
Playbook:
---
- hosts: k8s_kvm_vms
tasks:
- name: "update hostnames"
hostname:
name: "{{ new_hostname }}"
I think you need to sudo to change the hostname thus you should add "become: yes"
---
- hosts: k8s_kvm_vms
become: yes
tasks:
- name: "update hostnames"
hostname:
name: "{{ new_hostname }}"
How can I declare global variable within Ansible playbook. I have searched in google and found the below solution, but its not working as expected.
- hosts: all
vars:
prod-servers:
- x.x.x.x
- x.x.x.x
- hosts: "{{prod-servers}}"
tasks:
- name: ping
action: ping
When I'm trying the above code, it says variable prod-servers is undefined.
You cannot define a variable accessible on a playbook level (global variable) from within a play.
Variable Scopes
Ansible has 3 main scopes:
Global: this is set by config, environment variables and the command line
Play: each play and contained structures, vars entries (vars; vars_files; vars_prompt), role defaults and vars.
Host: variables directly associated to a host, like inventory, include_vars, facts or registered task outputs
Anything you declare inside a play can thus only be either a play variable, or a (host) fact.
To define a variable, which you can use in the hosts declaration:
run ansible-playbook with --extra-vars option and pass the value in the argument;
or to achieve the same functionality (decide which hosts to run a play on, from within a preceding play):
define an in-memory inventory and run the subsequent play against that inventory.
what you seem to want is an inventory (http://docs.ansible.com/ansible/latest/intro_inventory.html), it looks like you have an static list of IP's that may be prod servers (or dev, or whatever), therefore you can create an static inventory.
In your second play you want to use the list of IP's as hosts to run the tasks, that's not what Ansible expects. After the "hosts" keyword in a play declaration, Ansible expects a group name from the inventory.
If, on the opossite, your prod servers change from time to time, you may need to create a dynamic inventory. You can have a look at examples in https://github.com/ansible/ansible/tree/devel/contrib/inventory (for instance, there are examples of dynamic inventory based on EC2 from Amazon or vsphere)
regards
well, this can be done using
set_fact.
I don't know the best practice for this but this works for me
Here's my playbook example
- hosts: all
gather_facts: false
tasks:
- set_fact: host='hostname'
- hosts: host-name1
gather_facts: false
tasks:
- name: CheckHostName
shell: "{{ host }}"
register: output
- debug: msg="{{ output }}"
- hosts: host-name2
gather_facts: false
tasks:
- name: CheckHostName
shell: "{{ host }}"
register: output
- debug: msg="{{ output }}"