I'm trying to look for a text pattern in a load balancer host from a worker host, using the following:
- name: A play
hosts: workers
tasks:
- name: Look for text pattern in delegated host
delegate_to: load-balancer-host
find:
paths: "$ENVIRONMENT_VARIABLE/subdir"
file_type: file
patterns: file.pattern
contains: 'text pattern'
register: aVariable
The problem is that I can't found any way to make $ENVIRONMENT_VARIABLE (this variable exists in the load-balancer-host) available for the play (it contains the directory, in load-balancer-host, from where I want to look for). ansible_env is only available for the workers but not for the load-balancer-host
I have tried...
- name: A play
hosts: workers
tasks:
- name: set fact
set_fact:
env_var: "{{ lookup('env', 'ENVIRONMENT_VARIABLE') }}"
delegate_to: load-balancer-host
- name: debug
debug:
msg: "{{ env_var }}"
... too, but it prints an empty string.
For users running Ansible 1.x, see kfreezy's answer.
For users running Ansible 2.x, I have found the following solution:
- hosts: workers
tasks:
- name: gather facts from lb
setup:
delegate_to: load-balancer-host
delegate_facts: false
This task will make $ENVIRONMENT_VARIABLE available in every worker ansible_env var. If you want to make $ENVIRONMENT_VARIABLE available in the load-balancer-host ansible_env, just set delegate_facts to True.
More info in ansible docs
Personally I would simplify your playbook by either adding the $ENVIRONMENT_VARIABLE as a variable in Ansible (probably in the host_vars for load-balancer-host) or running a play against load-balancer-host rather than use delegate_to. It might not make sense depending on what the other tasks are.
Here's a direct answer to your question though.
load-balancer-host's ansible_env will only be defined when the host is included in the playbook. You can add another play against the 'load-balancer-host' that will just gather facts. Then you can reference the facts from 'load-balancer-host' using hostvars in your subsequent plays against 'workers'. He's what it would look like.
- hosts: load-balancer-host
tasks:
- name: print debug message
debug:
msg: "this play is for gathering facts on the LB"
- name: A play
hosts: workers
tasks:
- name: Look for text pattern in delegated host
delegate_to: load-balancer-host
find:
paths: "{{ hostvars['load-balancer-host'].ansible_env.ENVIRONMENT_VARIABLE }}/subdir"
file_type: file
patterns: file.pattern
contains: 'text pattern'
register: aVariable
Related
I am using set_fact and hostvars to pass variables between plays within a playbook. My code looks something like this:
- name: Staging play
hosts: localhost
gather_facts: no
vars_prompt:
- name: hostname
prompt: "Enter hostname or group"
private: no
- name: vault
prompt: "Enter vault name"
private: no
- name: input
prompt: "Enter input for role"
private: no
tasks:
- set_fact:
target_host: "{{ hostname }}"
target_vault: "{{ vault }}"
for_role: "{{ input }}"
- name: Execution play
hosts: "{{ hostvars['localhost']['target_host'] }}"
gather_facts: no
vars_files:
- "vault/{{ hostvars['localhost']['target_vault'] }}.yml"
tasks:
- include_role:
name: target_role
vars:
param: "{{ hostvars['localhost']['for_role'] }}"
This arrangement has worked without issue for months. However, our environment has changed and now I need to take a timestamp and pass that to the role as well as the other variable, so I made the following changes (denoted by comments):
- name: Staging play
hosts: localhost
gather_facts: yes # Changed from 'no' to 'yes'
vars_prompt:
- name: hostname
prompt: "Enter hostname or group"
private: no
- name: vault
prompt: "Enter vault name"
private: no
- name: input
prompt: "Enter input for role"
private: no
tasks:
- set_fact:
target_host: "{{ hostname }}"
target_vault: "{{ vault }}"
for_role: "{{ input }}"
current_time: "{{ ansible_date_time.iso8601 }}" # Added fact for current time
- name: Execution play
hosts: "{{ hostvars['localhost']['target_host'] }}"
gather_facts: no
vars_files:
- "vault/{{ hostvars['localhost']['target_vault'] }}.yml"
tasks:
- include_role:
name: target_role
vars:
param: "{{ hostvars['localhost']['for_role'] }}"
timestamp: "{{ hostvars['localhost']['current_time'] # Passed current_time to
Execution Play via hostvars
Now, when I execute, I get the error that the vault hostvars variable is undefined in the Execution Play. After some experimenting, I've found that setting gather_facts: yes in the Staging Play is what is triggering the issue.
However, I need gather_facts enabled in order to use ansible_time_date. I've already verified via debug that the facts are being recorded properly and can be called by hostvars within the Staging Play; just not in the following Execution Play. After hours of research, I can't find any reasoning for why gathering facts in the Staging Play should affect hostvars for the Execution Play or any idea on how to fix it.
At the end of the day, all I need is the current time passed to the included role. Anyone who can come up with a solution that actually works in this use case wins Employee of the Month. Bonus points if you can explain the initial issue with gather_facts.
Thanks!
So, I had to reinvent the wheel a bit, but came up with a much cleaner solution. I simply created a default value for a timestamp in the role itself and added a setup call for date/time at the appropriate point, conditional on there being no existing value for the variable in question.
- name: Gather date and time.
setup:
gather_subset: date_time
when: timestamp is undefined and ansible_date_time is undefined
I was able to leave gather_facts set to no in the dependent playbook but I still have no idea why setting it to yes broke anything in the first place. Any insight in this regard would be appreciated.
... if you can explain the initial issue with gather_facts ... Any insight in this regard would be appreciated.
This is caused by variable precedence and because Ansible do not "overwrite or set a new value" for a variable. So it will depend on when and where they become defined.
You may test with the following example
---
- hosts: localhost
become: false
gather_facts: false
tasks:
- name: Show Gathered Facts
debug:
msg: "{{ hostvars['localhost'].ansible_facts }}" # will be {} only
- name: Gather date and time only
setup:
gather_subset:
- 'date_time'
- '!min'
- name: Show Gathered Facts
debug:
msg: "{{ ansible_facts }}" # from hostvars['localhost'] again
and "try to break it" by adding
- name: Set Fact
set_fact:
ansible_date_time:
date: '1970-01-01'
- name: Show Facts
debug:
msg: "{{ hostvars['localhost'] }}"
Just like to note that for your use case you should use
gather_subset:
- 'date_time'
- '!min'
since your are interested in ansible_date_time only. See what is the exact list of Ansible setup min?.
Be also aware of caching facts since "When created with set_facts’s cacheable option, variables have the high precedence in the play, but are the same as a host facts precedence when they come from the cache."
The calling playbook has:
- hosts: ssh_servers
tasks:
- import_tasks: create_files.yml
Then, in create_files.yml, I'd like to run some tasks on hosts other than ssh_servers, such as:
- Hosts: other_servers
tasks:
- file:
I get: ERROR! conflicting action statements: hosts, tasks .
Is this because I'm trying to run against hosts that were never included in the calling task ?
Is there a way to accomplish this other than in the calling playbook have:
- hosts:
- ssh_servers
- other_servers
tasks:
- import_tasks: create_files.yml
Thank you.
Is this because I'm trying to run against hosts that were never included in the calling task ? Is there a way to accomplish this other than in the calling playbook
I believe the answer is yes, although it'll be weird and could cause subsequent folks who interact with your playbook some confusion
given a hypothetical create_files.yml of:
- name: create /tmp/hello_world on hosts "not_known_at_launch_time"
file:
path: /tmp/hello_world
state: present
delegate_to: '{{ item }}'
with_items: '{{ groups["not_known_at_launch_time"] }}'
then the glue needed to bridge them together is the dynamic creation of a group and that delegate_to: keyword
- hosts: ssh_hosts
tasks:
- add_host:
groups: not_known_at_launch_time
name: secret-host-0
ansible_host: 192.168.1.1 # or whatever
# ... other hostvars here ...
- include_tasks: create_files.yml
it may be possible to combine those inside create_files.yml, via some shared vars: that say which host-and-ip should be added to the magic group name, which also has the benefit of keeping the magic group name localized to the file that consumes it.
BE AWARE, I did actually test this, but not extensively, so there may be some weird things such as the need to run_once: yes on them to keep the tasks from being run groups.ssh_hosts|length times or similar stuff
As Vladimir correctly pointed out, what you actually want to happen is to make that relationship formal:
- hosts: ssh_hosts
tasks:
... whatever tasks you had before
- add_host: ... as before ...
- hosts: anonymous_group_name_goes_here
tasks:
- include_tasks: create_files.yml
- hosts: ssh_hosts
tasks:
- debug:
msg: and now you are back to the ssh_hosts to pick up what they were supposed to be doing when you stopped to post on SO
I try to run certain yaml tasks file for all hosts, as follows (main.yml):
- name: prepare nodes
include_tasks: node.yml node="{{ item }}"
loop: "{{ groups['all'] }}"
node.yml:
- block:
- name: Task 1...
...
- name: Task 100...
delegate_to: "{{ node }}"
However I get this error: Invalid options for include_tasks: node. I think it used to work in this manner. Anyway I tried to move loop from main.yml into node.yml (right after delegate_to). I also tried to skip node="{{ item }}" part. But I always get errors.
What is the proper way to apply a task file to several hosts within a role?
It should work if you put your node variable under vars then loop.
- name: include tasks
include_tasks: node.yml
vars:
node: '{{ item }}'
loop: "{{ groups['all'] }}"
Above code is working.
A play runs on the hosts you specified. You can run certain tasks on a subset of nodes using when.
But you can have multiple plays in a playbook. So you need to specify a play with hosts: all where you run the tasks you want to run everywhere and another one which runs the rest of the tasks.
Your playbook could look like this:
---
# This is a play
- name: run on all
hosts: all
vars:
somevar: 'test'
tasks:
- name: prepare nodes
include_tasks: node.yml
# This is another play
- name: run on group
hosts: hostgroup
vars:
somevar: 'example'
tasks:
- debug:
msg: 'This runs on all hosts in hostgroup'
# Both plays are in the same playbook
I'd like to pass a variable to an included Ansible playbook as follows:
---
- hosts: localhost
connection: local
vars:
my_group: foo
- include: site.yml hosts={{ my_group }}
Then, in site.yml...
---
- hosts: "{{ hosts }}"
...
Unfortunately, I get an error saying that my_group is undefined in site.yml. Ansible docs do say that:
Note that you cannot do variable substitution when including one playbook inside another.
Is this my case? Is there a way around it?
You can use this syntax, but my_group has to be defined at the global level. Now it's local to the first play - it's even clear from the indentation.
You can confirm this by running your playbook with --extra-vars my_group=foo.
But generally what you seem to want to achieve is done using in-memory inventory files and add_host module. Take this as an example:
- hosts: localhost
gather_facts: no
vars:
target_host: foo
some_other_variable: bar
tasks:
- add_host:
name: "{{ target_host }}"
groups: dynamically_created_hosts
some_other_variable: "{{ some_other_variable }}"
- include: site.yml
with site.yml:
---
- hosts: dynamically_created_hosts
tasks:
- debug:
var: some_other_variable
I added some_other_variable to answer the question from your comment "how do I make a variable globally available from inside a play". It's not global, but it's passed to another play as a "hostvar".
From what I see (and I can't explain why) in Ansible >=2.1.1.0, there must be an inventory file specified for the dynamic in-memory inventory to work. In older versions it worked with Ansible executed ad hoc, without an inventory file, but now you must run ansible-playbook with -i inventory_file or have an inventory file defined through ansible.cfg.
I have defined two group of hosts: wmaster and wnodes. Each group runs in its play:
- hosts: wmaster
roles:
- all
- swarm-mode
vars:
- swarm_master: true
- hosts: wnodes
roles:
- all
- swarm-mode
I use host variables (swarm_master) to define different behavior of some role.
Now, my first playbook performs some initialization and I need to share data with the nodes. What I did is to use set_fact in first play, and then to lookup in the second play:
- set_fact:
docker_worker_token: "{{ hostvars[smarm_master_ip].foo }}"
I don't like using the swarm_master_ip. How about to add a dummy host: global with e.g. address 1.1.1.1 that does not get any role, and serves just for holding the global facts/variables?
If you're using Ansible 2 then you can take use of delegate_facts during your first play:
- name: set fact on swarm nodes
set_fact: docker_worker_token="{{ some_var }}"
delegate_to: "{{ item }}"
delegate_facts: True
with_items: "{{ groups['wnodes'] }}"
This should delegate the set_fact task to every host in the wnodes group and will also delegate the resulting fact to those hosts as well instead of setting the fact on the inventory host currently being targeted by the first play.
How about to add a dummy host: global
I have actually found this suggestion to be quite useful in certain circumstances.
---
- hosts: my_server
tasks:
# create server_fact somehow
- add_host:
name: global
my_server_fact: "{{ server_fact }}"
- hosts: host_group
tasks:
- debug: var=hostvars['global']['my_server_fact']