Ansible multiple hosts for a specific playbook? - ansible

normally in ansible you always define a specific host for a specific playbook. But what is if I want to run a playbook for multiple hosts?
For a bit more clarity: I have following groups:
Webservers
Dev Clients
and following playbooks:
install main software
install certbot
install nginx
install vscode
For obvious reasons for sure the nginx playbook should have the entry: hosts: Webservers but what is with the main software playbook. This playbook should include both hosts.
In the end I want to have many different playbooks and groups and the only thing I wanna execute is: ansible-playbook ~/playbooks/webservers.yml and this triggers: "main software, certbot, nginx..." via includes. But this doesn't work without editing the hosts section of every playbook that is included in the webservers.yml.
Is it possible to tell a playbook that it should run on the hosts from the main-playbook which has included it?
like: webservers.yml -> hosts -> nginx.yml -> run on all clients which are entered in webservers.yml?
Does somebody of you has an idea? Or is this just not realizable with ansible?
Regards

You could use include module with when statement using group_names var as below:
webservers.yml
- hosts: all
tasks:
- name: Include Main Software playbook
include: main_software.yml
- name: Include Nginx playbook
include: nginx.yml
when: "'webservers' in {{ group_names }}"
- name: Include Vscode playbook
include: vscode.yml
when: "'DevClients' in {{ group_names }}"
Remember main_software.yml, nginx.yml and vscode.yml playbooks must have a list of tasks not a play.

Related

Ansible role dependencies and facts with delegate_to

The scenario is: I have several services running on several hosts. There is one special service - the reverseproxy/loadbalancer. Any service needs to configure that special service on the host, that runs the rp/lp service. During installation/update/deletion of a random service with an Ansible role, I need to call the ReverseProxy role on the specific host to configure the corresponding vhost.
At the moment I call a specific task file in the reverse proxy role to add or remove a vhost by the service with include_role and set some vars (very easy example without service and inventory specific vars).
- name: "Configure ReverseProxy"
include_role:
name: reverseproxy
tasks_from: vhost_add
apply:
delegate_to: "{{ groups['reverseproxy'][0] }}"
vars:
reverse_proxy_url: "http://{{ ansible_fqdn }}:{{ service_port }}/"
reverse_proxy_domain: "sub.domain.tld"
I have three problems.
I know, it's not a good idea to build such dependencies between roles and different hosts. I don't know a better way, especially if you think about the situation, where you need to do some extra stuff after creating the vhost (f.e. configure the service via REST API, which needs the external fqdn). In case of two separate playbooks with "backend"-service and "reverseproxy"-service - then I need a third playbook for configuring "hanging" services. Also I'm not sure, if I can retrieve the correct backend URL in the reverse proxy role (only think about the HTTP scheme or paths). That sounds not easy, or?
Earlier I had separate roles for adding/removing vhosts to a reverseproxy. This roles didn't have dependencies, but I needed to duplicate several defaults and templates and vars etc. which isn't nice too. Then I've changed that to a single role. Of course - in my opinion, this isn't really that, what a "role" should be. A role is something like "webserver" or "reverseproxy" (a state). But not something like "add_vhost_to_reverseproxy" (a verb). This would be something like a playbook - but is calling a parameterized playbook via a role a good idea/possible? The main problem is, that the state of reverseproxy is the sum of all services in the inventory.
In case of that single included role, including it, starts also all dependent roles (configure custom, firewall, etc.). Nevertheless in that case I found out, that the delegation did not use the facts of the delegated host.
I tested that with the following example - the inventory:
all:
hosts:
server1:
my_var: a
server2:
my_var: b
children:
service:
hosts:
server1:
reverseproxy:
hosts:
server2:
And playbook which assigns a role-a to the group webserver. The role-a has a task like:
- block:
- setup:
- name: "Include role b on delegated {{ groups['reverseproxy'][0] }}"
include_role:
name: role-b
delegate_to: "{{ groups['reverseproxy'][0] }}"
delegate_facts: true # or false or omit - it has no effect on Ansible 2.9 and 2.10
And in role-b only outputing the my_var of the inventory will output
TASK [role-b : My_Var on server1] *******************
ok: [server1 -> <ip-of-server2>] =>
my_var: a
Which says me, that role-b that should be run on server2 has the facts of server1. So - configuring the "reverseproxy" service is done in context of the "backend"-service. Which would have several other issues - when you think about firewall-dependencies etc. I can avoid that, by using tags - but then I need to run the playbook not just with the tag of the service, but also with all tags I want to configure, and I cannot use include_tasks with args-apply-tags anymore inside a role that also includes other roles (the tags will applied to all subtasks...). I miss something like include_role but only that specific tags or ignore dependencies. This isn't a bug, but has possible side effects in case of delegate_to.
I'm not really sure, what is the question? The question is - what is a good way to handle dependencies between hosts and roles in Ansible - especially when they are not on the same host?
I am sure I do not fully understand your exact problem, but when I was dealing with load balancers I used a template. So this was my disable_workers playbook:
---
- hosts: "{{ ip_list | default( 'jboss' ) }}"
tasks:
- name: Tag JBoss service as 'disabled'
ec2_tag:
resource: "{{ ec2_id }}"
region: "{{ region }}"
state: present
tags:
State: 'disabled'
delegate_to: localhost
- action: setup
- hosts: httpd
become: yes
become_user: root
vars:
uriworkermap_file: "{{ httpd_conf_dir }}/uriworkermap.properties"
tasks:
- name: Refresh inventory cache
ec2_remote_facts:
region: "{{ region }}"
delegate_to: localhost
- name: Update uriworkermap.properties
template:
backup: yes
dest: "{{ uriworkermap_file }}"
mode: 0644
src: ./J2/uriworkermap.properties.j2
Do not expect this to work as-is. It was v1.8 on AWS hosts, and things may have changed.
But the point is to set user-defined facts, on each host, for that host's desired state (enabled, disabled, stopped), reload the facts, and then run the Jinja template that uses those facts.

Dynamicly set HTTP_PROXY in an ansible playbook

I'm running a playbook either on a bunch of servers with no need of http_proxy and others with needs of it (on different runs).
I've read https://docs.ansible.com/ansible/latest/user_guide/playbooks_environment.html but it doesn't really answer this...
here's an example:
- hosts: all
tasks:
- name: install vi
become: true
apt:
name: vi
state: present
I would like to launch it with a group of servers (let's say server01-atlanta) without proxy and in another run with a group of servers (let's say server01-berlin) with proxy and without changing the code between each run (so managing to do it with inventory variables).
I would
You can solve this with group_vars / host_vars in combination with environment variables. Her is a simple example based on the code from ansible docs.
---
- hosts: all
vars:
proxy: # default empty
tasks:
- apt: name=cobbler state=installed
environment:
http_proxy: "{{ proxy }}"
This is how you define a environment variable per task. You can also use normal ansible variables for this. There is also a example with proxy settings and variables in the docs. See: https://docs.ansible.com/ansible/latest/user_guide/playbooks_environment.html
In your inventory you can define the proxy variable per host or group:
atlanta:
hosts:
host1:
host2:
vars:
proxy: proxy.atlanta.example.com
See inventory docs for more details: https://docs.ansible.com/ansible/latest/user_guide/intro_inventory.html#host-variables
For anyone wondering you can also set this via the command line with the following:
ansible-playbook --extra-vars "http_proxy=$http_proxy" ...
As found here

Ansible - vars are not correctly propagated to handlers when role run in loop

I am asking for help with a problem of deploying multiple versions (different variables) of the app with the same role run from one playbook.
We have an app with multiple product families, which are different code versions. Each version has separate uWSGI vassal config and Nginx virtualhost config(/api/v2, /api/v3, ...).
The desired state would be to run playbook and configure the server with all versions specified.
Sadly, ansible's import_role/import_tasks can't be used with with_items, so include_role/include_tasks must be used (pitty because they do not honor role tags).
The include_role method would not be the biggest problem, but we use handlers to notify uWSGI touch to reload - on a code change, link change, virtualenv change, app_config change, ...).
But when using loop (with_items), the variables passed from the loop does not correctly propagate to handlers.
I tried this scenarios
playbook.yml - with_items loop inside the playbook
PROBLEM: Handler is run only for the first iteration of the loop.
#!/usr/bin/env ansible-playbook
# HAndler is run only once, from first notifier
- hosts: localhost
gather_facts: no
vars:
app_root: "/tmp/test_ansible"
app_versions:
- app_product_family: 1
app_release: "v1.0.2"
- app_product_family: 3
app_release: "v4.0.7"
tasks:
- name: Deploy multiple versions of app
include_role:
name: app
with_items: "{{ app_versions }}"
loop_control:
loop_var: app_version
vars:
app_product_family: "{{ app_version.app_product_family }}"
app_release: "{{ app_version.app_release }}"
tags:
- app
- app_debug
playbook_v2.yml - with_items loop inside role task
PROBLEM: Handler is run with the default value from "Defaults"
#!/usr/bin/env ansible-playbook
- hosts: localhost
gather_facts: no
roles:
- app_v2
vars:
app_v2_root: "/tmp/test_ansible_v2"
app_v2_versions:
- app_v2_product_family: 1
app_v2_release: "v1.0.2"
- app_v2_product_family: 3
app_v2_release: "v4.0.7"
Tasks roles/app_v2/main.yml
---
# Workaround because import_tasks can't be run with_items
- include_tasks: deploy.yml
when: app_v2_versions
with_items: "{{ app_v2_versions }}"
loop_control:
loop_var: app_v2
vars:
app_v2_product_family: "{{ app_v2.app_v2_product_family }}"
app_v2_release: "{{ app_v2.app_v2_release }}"
tags:
- app_v2
- app_v2_deploy
...
One idea was about writing a separate role for each product family, but they share nginx and uWSGI, so it will be lots of copy-pasting and sharing tasks (so tags would not work properly).
For now, I solved it with shell script wrapper, but this is not an ideal solution and does not work from Ansible tower.
Sample repo with tasks to reproduce problem (tested with ansible 2.4, 2.5, 2.6)
Any ideas & recommendations are very welcome.
The order of overrides for variables is broken for includes in Ansible. F.e. even set_fact in the included role will be shadowed by role defaults.
See this bug: https://github.com/ansible/ansible/issues/22025
It's closed but not fixed. My advice: use include and variables really carefully.
In practice I never use role includes with loop. If you need loop, include a tasklist in this loop (and that tasklist, in turn, may import_role).
Ok, It is a bug as #George Shuklin posted.
I will use my shell wrapper, which reads group_vars yaml and then runs the playbook multiple times according to the variable list length.
Sadly I hit multiple annoying bugs in ansible in last few weeks, kinda losing my trust in it ):
And probably everybody is using microservices and kubernetes, so need to speed up our migration (:

Is there a better way to conditionally add a user to a group with Ansible?

I have a playbook that provisions a host for use with Rails/rvm/passenger. I'd like to add use the same playbook to setup both test and production.
In testing, the user to add to the rvm group is jenkins. The one in production is passenger. My playbook excerpt below does this based on the inventory_hostname parameter.
It seems like adding a new user:/when: block in the playbook for every testing or production host is the wrong way to go here. Should I be using an Ansible role for this?
Thanks
---
- hosts: all
become: true
...
tasks:
- name: add jenkins user to rvm group when on testing
user: name={{ item }}
shell=/bin/bash
groups=rvm
append=yes
with_items:
- jenkins
when: "'bob.mydomain' in inventory_hostname"
- name: add passenger user to rvm group when on rails production
user: name={{ item }}
shell=/bin/bash
groups=rvm
append=yes
with_items:
- passenger
when: "'alice.mydomain' in inventory_hostname"
Create an inventory file called inventories/testing
[web]
alice.mydomain
[testing:children]
web
This will control what hosts are targeted when you run your playbook against your testing environment.
Create another file called group_vars/testing
rvm_user: jenkins
This file will keep all variables required for running a playbook against the testing environment. Your production file should have the same variables, but with different values.
Finally in your playbook:
---
- hosts: all
become: true
...
tasks:
- name: add user to rvm group
user:
name: "{{ rvm_user }}"
shell: "/bin/bash"
groups: rvm
append: yes
Now, when you want to run your playbook, you execute it like so:
ansible-playbook -i inventories/testing site.yml
Ansible will do the right thing, and look for a testing file in group_vars and read variables from there. It will ignore variables in a file or folder not named after your environment with the exception of a file called all which is intended to be for common variables across playbooks.
Good luck - Ansible is an amazing tool :)

Can I force current hosts group to be identified as another in a playbook include?

The current case is this:
I have a playbook which provisions a bunch of servers and installs apps to these servers.
One of these apps already has it's own ansible playbook which I wanted to use. Now my problem arises from this playbook, as it's limited to hosts: [prod] and the host groups I have in the upper-level playbook are different.
I know I could just use add_host to add the needed hosts to a prod group, but that is a solution which I don't like.
So my question is: Is there a way to add the current hosts to a new host group in the include statement?
Something like - include: foo.yml prod={{ ansible_host_group }}
Or can I somehow include only the tasks from a playbook?
No, there's no direct way to do this.
Now my problem arises from this playbook, as it's limited to
hosts: [prod]
You can setup host's more flexible via extra vars:
- name: add role fail2ban
hosts: '{{ target }}'
remote_user: root
roles:
- fail2ban
Run it:
ansible-playbook testplaybook.yml --extra-vars "target=10.0.190.123"
ansible-playbook testplaybook.yml --extra-vars "target=webservers"
Is this workaround suitable for you?

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