Facts and conditionals

Gathering info

Gathering facts may be costly – use setup for specific machines you want to check. * If gather_facts is enabled, we can use it to verify system facts * And set the task blocks accordingly * Use when for conditionals * Or variables with the assert module

Docs

# Example Gathering info
gather_facts: true 
task:
    - name: Veryfie that this si the debian dirsto 
      when: "'Debian' is ansiable_fact['distribiution']"
      block:
        - name: This is Debian
        - ansible.builtin.debug:
                - msg: This is Debian

User defined facts

Create /etc/ansible/facts.d on the managed nodes
- The file has tave to have .fact extentsion - Has to be in the Json Format or .ini
- Theare stored in ansible_facts[’ansible_local’]

Managing Software and repos

U can provide a list to the package argument instead of looping over the packages

Downloading the local repo

Ansible doesn't provide the module for creating the repos u have to do it manually

Also there's a rmp_key module for downloading the gpg keys

# Example downloading and creating a local repo
- name: make directory
file:
path: /var/ftp/repo
state: directory
- name: download packages
yum:
name: nmap
download_only: yes
download_dir: /var/ftp/repo
- name: createrepo
command: createrepo /var/ftp/repo

Managing subscriptions

There are two models that deal with the subscription management

red hat_subscription Subscription and Registration in one task
rhsm_repository add subscription manager repos

Example Using subscription manager to set up Ansible

---
- name: register and subscribe ansible5
redhat_subscription:
username: bob@example.com
password: verysecretpassword
state: present
- name: configure additional repo access
  rhsm_repository:
- name:
  - rh-gluster-3-client-for-rhel-8-x86_64-
  rpms
    - rhel-8-for-x86_64-appstream-debug-rpms

Commands

Docs

Defining Targets

You can also specify multiple hosts and groups by separating them with colons:

# Exmaple  Test Host connection
ansible server1:server2:dbservers -i inventory -m ping
ansible all -i inventory -m ping

Runing modules

Probably u will need to use the setup module
- Docs
To execute a module with arguments, include the -a flag followed by the appropriate options in double quotes
- U can use whatever the cmd with -a

ansible -i hosts servers -m setup -a 'filter: ansible_distribution'

ansible servers -i hosts -m file -a 'state: directory'

ansible <target group> -i inventory -m module -a "module options"

Setup module

pages of information about the server that can be used as variable in the playbooks later

Ansible Debuging

U can skip the deubiging message by using etiher the: * Verbosity Level in ur playbook Just use -vvv flag

# Example running playbok withthe different verbosity  up to 6
ansible-playbook all playboo.yml -vvv

U can also prettyfie the ansible message in ansible.cfg

Useful modules

Uri
- To perform quick checks and so on
Stat
- stat the files and dirs

Assert

- name: check if file size is valid
  assert:
    that:
    - "{{ (filesize | int) <= 100 }}"
    - "{{ (filesize | int) >= 1 }}"
    fail_msg: "file size must be between 0 and
    100"
    success_msg: "file size is good, let\’s
    continue"

- name: create a file
  command: dd if=/dev/zero of=/bigfile bs=1
  count={{ filesize }}

Name	Use
command	Runs arbitrary commands but not using a shell
shell	Runs arbitrary commands using a shell
raw	Runs commands directly on top of SSH without using Python
copy	Copies files or lines of text to files
yum	Manages packages on RHEL family-managed hosts
service	Manages the current state of systemd and system-V services
ping	Checks whether managed hosts are in a manageable state

# raw  is used to do it over ssh without the python  so can be used for installing things for ansible
ansible -u root -i inventory ansible3 --ask-pass -m raw -a “yuminstall python3"

Execution Modes

Check Mode

Some modules don't support the check mode check_mode: yes yes can be used with any task it also overwrites the entire playbook

Diff mode --diff

Display changes in file contents

ansible-playbook playbook.yml --diff

#  Output:
# --- before: /etc/myconfig.conf
# +++ after: /etc/myconfig.conf
# @@ -1,3 +1,3 @@
#  setting1 = true
# -setting2 = old_value
# +setting2 = new_value
#  setting3 = enabled

Mange task tags and list task

List the task

ansible     --list-task <playbook>
ansible     --list-task <playbook>