How to execute alternating roles in Ansible? - ansible

I need to somehow loop over a list of variables and execute both of the below roles once for each iteration, on each iteration passing a variable to the role. For example, given a variable list of 100-101, I need to execute in the order role1:100, role2:100, role1:101, role2:101. The variables 100-100 should be passed to the tasks inside the role.
---
- hosts: group1
tasks:
- include_role:
name: role1
- hosts: group2
tasks:
- include_role:
name: role2
I was looking at the below answer as a possible solution but I am not sure how to adapt it to my needs. Can the above scenario be accomplished in Ansible?
Ansible: How to iterate over a role with an array?

Loop over the Cartesian product of variables and role names:
vars:
roles_to_include:
- role1
- role2
values_to_pass:
- 100
- 101
tasks:
- include_role:
name: "{{ item.1 }}"
vars:
my_variable: "{{ item.0 }}"
loop: "{{ values_to_pass | product(roles_to_include) | list }}"

Related

Ansible: Retrieve Data from inventory

I need to retrieve the IP of bob_server from the inventory file. I am not clear as to what combination to use in filter, lookup, and when? Depending on the inventory filebob_server and alice_server names can change, but app_type won't change. My playbook logic is obviously wrong, Can someone guide me the correct way to fetch IP address when app_type = bob
My current Inventory file:
---
all:
hosts:
children:
bob_server:
hosts: 10.192.2.6
vars:
app_type: bob
alice_server:
hosts: 10.192.2.53
vars:
app_type: alice
My Playbook
---
- hosts: localhost
name: Retrive data
tasks:
- name: Set Ambari IP
set_fact:
ambariIP: "{{ lookup('hosts', children) }}"
when: "hostvars[app_type] == 'bob'"
Given the inventory
shell> cat hosts-01
---
all:
hosts:
children:
bob_server:
hosts: 10.192.2.6
vars:
app_type: bob
alice_server:
hosts: 10.192.2.53
vars:
app_type: alice
The simple option is using ansible-inventory, e.g.
- hosts: localhost
tasks:
- command: ansible-inventory -i hosts-01 --list
register: result
- set_fact:
my_inventory: "{{ result.stdout|from_yaml }}"
- debug:
var: my_inventory.bob_server.hosts
gives
my_inventory.bob_server.hosts:
- 10.192.2.6
If you want to parse the file on your own read it into a dictionary and flatten the paths, e.g. (install ansible.utils ansible-galaxy collection install ansible.utils)
- include_vars:
file: hosts-01
name: my_hosts
- set_fact:
my_paths: "{{ lookup('ansible.utils.to_paths', my_hosts) }}"
- debug:
var: my_paths
gives
my_paths:
all.children.alice_server.hosts: 10.192.2.53
all.children.alice_server.vars.app_type: alice
all.children.bob_server.hosts: 10.192.2.6
all.children.bob_server.vars.app_type: bob
all.hosts: null
Now select the keys ending bob_server.hosts
- set_fact:
bob_server_hosts: "{{ my_paths|
dict2items|
selectattr('key', 'match', '^.*bob_server\\.hosts$')|
items2dict }}"
gives
bob_server_hosts:
all.children.bob_server.hosts: 10.192.2.6
and select the IPs
- set_fact:
bob_server_ips: "{{ bob_server_hosts.values()|list }}"
gives
bob_server_ips:
- 10.192.2.6
The inventory is missing the concept of groups. See Inventory basics: formats, hosts, and groups. Usually, the value of children is a group of hosts. In this inventory, the value of children is the single host. This is conceptually wrong but still valid, .e.g
- hosts: bob_server
gather_facts: false
tasks:
- debug:
var: inventory_hostname
gives
shell> ansible-playbook -i hosts-01 playbook.ym
...
TASK [debug] ****************************************************
ok: [10.192.2.6] =>
inventory_hostname: 10.192.2.6

A method for listing Ansible modules used by playbooks

I'm creating a requirements.yml in an Ansible project, and I want to identify all of the modules that need to be installed from ansible-galaxy that are used by project playbooks. ansible-doc --list --playbook-dir foo seems like the right tool for the job, but it lists all locally available modules, not just the ones which are actually used in the foo directory. ansible-galaxy list doesn't account for any which are needed but not installed.
Is there a way to do this where I don't end up writing a shell script to sed|awk|grep the info I want?
The best approach I've been able to come up with so far is to ansible-playbook --syntax-check each of the playbooks. This will throw errors such as
ERROR! the role 'foo' was not found ...
ERROR! couldn't resolve module/action 'bar'. This often indicates a misspelling, missing collection, or incorrect module path.
but this is not ideal because it exits as soon as any error occurs. I have to fix each one and run the syntax check again.
FWIW, as a concept, the playbook below lists the modules used in a role
- hosts: localhost
vars:
keywords:
- always
- become
- block
- loop
- loop_control
- name
- notify
- register
- tags
- vars
- when
tasks:
- name: The variable my_role_path is mandatory
assert:
that: my_role_path|d('')|length > 0
- name: Find tasks files
find:
path: "{{ my_role_path }}/tasks"
patterns: '*.yml,*.yaml'
recurse: true
register: result
- name: Create list of tasks
set_fact:
lft: "{{ lft|d([]) + lookup('file', item)|from_yaml }}"
loop: "{{ result.files|map(attribute='path')|list }}"
- name: Get list of keys
set_fact:
lfk: "{{ lfk|d([]) + item.keys()|list }}"
loop: "{{ lft }}"
- name: Get list of keys from block/rescue/always
set_fact:
lfk: "{{ lfk|d([]) + item.keys()|list }}"
loop: "{{ lft|json_query('[].[block, rescue, always]')|flatten }}"
- name: Display list of modules
debug:
var: lfk|unique|sort|difference(keywords)
For example, analyze the role systemd
shell> ansible-playbook pb.yml -e my_role_path=roles/ansible-role-systemd
...
lfk|unique|sort|difference(keywords):
- command
- file
- include_tasks
- meta
- systemd
- template
Complete the list of the keywords.
Use the tasks below to analyze a playbook
tasks:
- name: The variable my_playbook_path is mandatory
assert:
that: my_playbook_path|d('')|length > 0
- name: Create list of tasks
set_fact:
lft: "{{ _playbook|map(attribute='tasks')|flatten }}"
vars:
_playbook: "{{ lookup('file', my_playbook_path)|from_yaml }}"
- name: Get list of keys
set_fact:
lfk: "{{ lfk|d([]) + item.keys()|list }}"
loop: "{{ lft }}"
- name: Get list of keys from block/rescue/always
set_fact:
lfk: "{{ lfk|d([]) + item.keys()|list }}"
loop: "{{ lft|json_query('[].[block, rescue, always]')|flatten }}"
- name: Display list of modules
debug:
var: lfk|unique|sort|difference(keywords)
For example, analyzing the first playbook gives
lfk|unique|sort|difference(keywords):
- assert
- debug
- find
- set_fact

Ansible how to set_fact with condition or var base on condition

I have 3 types of servers: dev, qa and prod. I need to send files to server specific home directories, i.e:
Dev Home Directory: /dev/home
QA Home Directory:/qa/home
PROD Home Directory: /prod/home
I have var set as boolean to determine the server type and think of using set_fact with condition to assign home directories for the servers. My playbook looks like this:
---
- hosts: localhost
var:
dev: "{{ True if <hostname matches dev> | else False }}"
qa: "{{ True if <hostname matches qa> | else False }}"
prod: "{{ True if <hostname matches prod> | else False }}"
tasks:
- set_facts:
home_dir: "{{'/dev/home/' if dev | '/qa/home' if qa | default('prod')}}"
However, then I ran the playbook, I was getting error about 'template expected token 'name', got string> Anyone know what I did wrong? Thanks!
Use match test. For example, the playbook
shell> cat pb.yml
- hosts: localhost
vars:
dev_pattern: '^dev_.+$'
qa_pattern: '^qa_.+$'
prod_pattern: '^prod_.+$'
dev: "{{ hostname is match(dev_pattern) }}"
qa: "{{ hostname is match(qa_pattern) }}"
prod: "{{ hostname is match(prod_pattern) }}"
tasks:
- set_fact:
home_dir: /prod/home
- set_fact:
home_dir: /dev/home
when: dev|bool
- set_fact:
home_dir: /qa/home
when: qa|bool
- debug:
var: home_dir
gives (abridged)
shell> ansible-playbook pb.yml -e hostname=dev_007
home_dir: /dev/home
Notes:
The variable prod is not used because /prod/home is default.
prod/home is assigned to home_dir first because it's the default. Next tasks can conditionally overwrite home_dirs.
Without the variable hostname defined the playbook will crash.
A simpler solution that gives the same result is creating a dictionary of 'pattern: home_dir'. For example
- hosts: localhost
vars:
home_dirs:
dev_: /dev/home
qa_: /qa/home
prod_: /prod/home
tasks:
- set_fact:
home_dir: "{{ home_dirs|
dict2items|
selectattr('key', 'in' , hostname)|
map(attribute='value')|
list|
first|default('/prod/home') }}"
- debug:
var: home_dir
Adding an alternative method to achieve this. This kind of extends the group_vars suggestion given by #mdaniel in his comment.
Ansible has a ready-made mechanism to build the variables based on the inventory hosts and groups. If you organize your inventory, you can avoid a lot of complication in trying to match host patterns.
Below is a simplified example, please go through the link above for more options.
Consider an inventory file /home/user/ansible/hosts:
[dev]
srv01.dev.example
srv02.dev.example
[qa]
srv01.qa.example
srv02.qa.example
[prod]
srv01.prod.example
srv02.prod.example
Using group_vars:
Then you can have below group_var files in /home/user/ansible/group_vars/ (matching inventory group names):
dev.yml
qa.yml
prod.yml
In dev.yml:
home_dir: "/dev/home"
In qa.yml:
home_dir: "/qa/home"
In prod.yml:
home_dir: "/prod/home"
Using host_vars:
Or you can have variables specific to hosts in host_vars directory /home/user/ansible/host_vars/:
srv01.dev.example.yml
srv01.prod.example.yml
# and so on
In srv01.dev.example.yml:
home_dir: "/dev/home"
In srv01.prod.example.yml:
home_dir: "/prod/home"
These variables will be picked based on which hosts you run the playbook, for example the below playbook:
---
- hosts: dev
tasks:
- debug:
var: home_dir
# will be "/dev/home"
- hosts: prod
tasks:
- debug:
var: home_dir
# will be "/prod/home"
- hosts: srv01.dev.example
tasks:
- debug:
var: home_dir
# will be "/dev/home"
- hosts: srv01.prod.example
tasks:
- debug:
var: home_dir
# will be "/prod/home"

How to deal with errors coming from ansible roles

I have been calling a playbook having multiple roles, each roles signifies a TESTCASE. I need to run the playbook without failing it if one of the role fails during execution. For which I am using ignore_errors: yes. However, this truly ignores error, I need to print at the end the name of the ROLES which are failed ? is it possible ?
- hosts: WEB
gather_facts: no
vars:
roles:
- { role: CHECK_CONNECTION, ignore_errors: yes, tags: always }
- { role: CHECK_CPU, ignore_errors: yes, tags: always }
- { role: CHECK_MEM, ignore_errors: yes, tags: always }
Question: How to execute whole playbook and at the end print the failed roles ?
An option would be to use the rescue section of Blocks
Create include_role.yml
- name: include role
block:
- include_role:
name: "{{ item_my_role }}"
rescue:
- set_fact:
failed_roles: "{{ failed_roles|default([]) + [ item_my_role ] }}"
and loop include_tasks. It is not possible to loop blocks.
vars:
my_roles:
- CHECK_CONNECTION
- CHECK_CPU
- CHECK_MEM
tasks:
- include_tasks: include_role.yml
loop: "{{ my_roles }}"
loop_control:
loop_var: item_my_role
- debug:
var: failed_roles|default([])
Use loop_control loop_var and create unique variable, e.g. item_my_role, avoiding potential conflict inside the included role. If the variable is used inside the included role the following rescue section will add the wrong item to the list.

Conditionally joining two lists or taking the first and saving it in a variable

I have a role for a vpn server and some of them should be accessible to everyone, others only to admins.
Users and admins do not intersect, I want to use the variable only_admins that is True or False to toggle between these two.
I came up with this piece of configuration:
- name: Set vpn_users variable
set_fact: "vpn_users={{ users + admins}}"
when: ! only_admins
- name: Set vpn_users variable
set_fact: "vpn_users={{ admins }}"
when: only_admins
# works
- debug: "var={{ item }}"
with_items: users
# works
- debug: "var={{ item }}"
with_items: admins
# does not work
- debug: "var={{ item }}"
with_items: vpn_users
Any tips to get this working? Or other approaches?
Your syntax for set_fact is not good as per the documentation (http://docs.ansible.com/set_fact_module.html). You also use a lot of unnecessary quoting.
Here is a self-contained example that works fine :
---
- hosts: localhost
vars:
users:
- ua
- ub
admins:
- aa
- ab
tasks:
- debug: var=only_admins
- name: Set vpn_users variable to admins and users
set_fact:
vpn_users: "{{ users + admins }}"
when: not only_admins
- name: Set vpn_users variable to admins only
set_fact:
vpn_users: "{{ admins }}"
when: only_admins
- debug: var=item
with_items: users
- debug: var=item
with_items: admins
- debug: var=item
with_items: vpn_users
Try it with :
ansible-playbook test.yml --extra-vars '{ "only_admins": false }'
or :
ansible-playbook test.yml --extra-vars '{ "only_admins": true }'
Note that for debugging, you can print whatever var you'd like with the debug module. So instead of doing :
- debug: var=item
with_items: vpn_users
you just can do :
- debug: var=vpn_users
(ditto for the two preceding tasks).
This seems to work, didn't find out why the set_fact didn't work though:
- debug: "var={{ item }}"
with_items: "{{ admins if only_admins else (admins + users) }}"

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