Ansible

An introduction to configuration and state management

How to Navigate Through this Presentation

  • Space to progress incrementally
  • Arrow keys to navigate
  • Alt + Click to zoom in on a slide (Again to zoom out)
  • Orange text is a link

Building Information

Important stuff like bathrooms/emergency exits and meeting points for anyone that hasn't visited before.

What we'll cover

  • What is Ansible
  • Foundation principals (building blocks)
  • Making it work (Playbooks and Modules)
  • Making it right (Refactoring)
  • Troubleshooting and Validation
  • Real World Examples (Time Allowing)

Questions!

What Is Ansible

Configuration Management

Stores the state of infrastructure as code.

  • Reproducible
  • Reduces Human Error
  • Easier to find issues (peer review/automated testing/static analysis)
  • Auditing (Who/What/When/Where)

Why not just use a script?

  • Cross Platform
  • Automation ready
  • Templating and Variables
  • Modular and Reusable
  • Idempotence (State management)
  • "Intuitive"

Why Ansible?

Ansible vs. other CM tools

Positives:

  • Agentless
  • SSH as connection protocol
  • Playbooks can be run from anywhere, not just the "Master" server/s
  • "Batteries Included"

Negatives:

  • Performance on large scale
  • Windows not supported as control.

Environment Setup

Topology

Control Machine Setup

  • Installation via most package managers
  • Also available via python-pip
  • Windows as a control machine is not supported (except via Docker)
pip install ansible

Documentation

Installation on Ubuntu

Documentation

sudo apt-get update
sudo apt-get install software-properties-common
sudo apt-add-repository --yes --update ppa:ansible/ansible
sudo apt-get install ansible -y
ansible --version # Should be > 2.9

Remote Host Setup

ssh-keygen -f $HOME/.ssh/id_rsa -t rsa -b 4096 -N "" 
ssh-copy-id $REMOTE_HOST
ssh $REMOTE_HOST
  • Ansible requires SSH access to remote hosts
    • Can be password/less
    • Possible to run in pull-mode
  • Requires "python-simplejson" package installed
ansible all -b -K -m raw -a "apt-get install -y python-simplejson"

The Basics

Before we dive in

Ansible's configuration lives in "/etc/ansible".

sudo chown -R training:training /etc/ansible

In order to change files in this directory, we need to have permissions to do so

Inventory

  • /etc/ansible/hosts
  • Where we define the hosts we want to work on
  • Can be static or dynamic
  • Comprised of groups of entries of hostnames
  • Can be in INI or YAML format
  • Can also include extra detail if needed

Documentation

ansible --list-hosts all

Hosts File Layout

  • One host per line
  • Either hostname or IP
  • Can be grouped with a header in square brackets
[loadbalancer]
john-proxy01

[webserver]
john-web01
john-web02

[database]
john-database01

[control]
john-control01

More Hosts File Config

  • Parent/Children Relationships
[demo_app:children]
loadbalancer
webserver
database
  • Variables
[control]
john-control01 ansible_connection=local
[loadbalancer]
johns-proxy01 # Is the same as
johns-proxy01.$DOMAIN # Is also the same as
192.168.0.10 # Is also the same as
some_stupid_hostname ansible_host=johns-proxy01

Referencing groups

  • Default groups (all/ungrouped)
  • Globbing works too!
  • Reference your groups
  • Individual hosts
  • Multiple groups
  • Indexing
  • Negation

Documentation

ansible --list-hosts all
ansible --list-hosts "*"
ansible --list-hosts control
ansible --list-hosts john-proxy01
ansible --list-hosts control,webserver
ansible --list-hosts webserver[0]
ansible --list-hosts \!control

Ad-hoc Commands

  • Simple commands that complete a single action
  • Great to learn how Ansible works
  • Also for commands that don't need to run twice
  • There is usually a better way (playbooks)
ansible all -m ping
ansible all -m command -a "hostname" # Is the same as
ansible all -a "hostname"
ansible all -a "/bin/false"

Documentation

ansible $HOSTS -m $MODULE -a $MODULE_ARGUMENTS

More on Ad-Hoc

  • More options are available
ansible control -b -K -m copy -a \
"dest=/etc/sudoers.d/sudo_nopasswd mode=0660 \
content='%sudo ALL=(ALL) NOPASSWD: ALL' validate='visudo -cf %s'"

ansible all -b -m ping
ansible control -m copy -a "dest=/tmp/foo content=''" -C
ansible control -m copy -a "dest=/tmp/foo content=''"
ansible control -m copy -a "dest=/tmp/foo content=''"

ansible control -m ping -b
  • Let's fix that

The Playbook

What are Playbooks?

  • The meat of Ansible!
  • Everything is either in or referenced by a playbook
  • Usually live in /etc/ansible/playbooks
  • A way to group and order tasks
  • Written in YAML
  • Consists of the target hosts and the tasks you would like to run against those hosts.

Documentation

YAML?

  • File optionally starts with "---" and ends with "..."
  • Consists of (In Ansible) dictionaries and lists

Documentation

Lists with '-'

  • 2 spaces on each new line

Dictionaries are denoted with ':'

---
Fruits:
  - Apple
  - Banana
  - Pear
---
Key: Value
---
foo: "{{ variable }}"

Variables like '"{{  }}"'

My First Playbook

mkdir playbooks
vim playbooks/hostname.yml
ansible-playbook playbooks/hostname.yml
---
- hosts: all
  tasks:
    - name: Print server hostname
      command: hostname
ansible all -a "hostname"

Static Checks

Documentation

  • "--syntax-check" checks a YAML file for compatibility with Ansible
    • Doesn't run the playbook
    • Great for use in CI testing
ansible-playbook playbooks/hostname.yml --syntax-check

Make It Work

But How?

As we write a playbook to provision each application, we'll approach it in 4 steps:

  • Packages
  • Service Management
  • System Configuration
  • Application Configuration

And at each step, we'll approach it in the same way:

  • Pick a module
  • Find what arguments it needs
  • Try it!

Anatomy of a Module

Lets take a look at the 'apt' module as an example:

  • Synopsis
  • System Requirements
  • Options
    • Name
    • Required?
    • Default?
    • Choices
    • Comments
  • Examples

Packages - apt

Documentation

---
- hosts: loadbalancer
  tasks:
    - name: Install nginx
      apt:
        name: nginx
        state: present

playbooks/loadbalancer.yml

---
- hosts: database
  tasks:
    - name: Install mysql-server
      apt:
        name: mysql-server
        state: present

playbooks/database.yml

ansible-playbook playbooks/loadbalancer.yml

Become

playbooks/loadbalancer.yml

playbooks/database.yml

ansible-playbook playbooks/loadbalancer.yml
ansible-playbook playbooks/database.yml
---
- hosts: loadbalancer
  become: true
  tasks:
    - name: Install nginx
      apt:
        name: nginx
        state: present
---
- hosts: database
  become: true
  tasks:
    - name: Install mysql-server
      apt:
        name: mysql-server
        state: present

Documentation

loop

playbooks/webserver.yml

ansible-playbook playbooks/webserver.yml
---
- hosts: webserver
  become: true
  tasks:
    - name: Install apache2
      apt:
        name: apache2
        state: present

Documentation

---
- hosts: webserver
  become: true
  tasks:
    - name: Install apache2
      apt:
        name: apache2
        state: present
    - name: Install libapache2-mod-wsgi
      apt:
        name: libapache2-mod-wsgi
        state: present
    - name: Install python-pip
      apt:
        name: python-pip
        state: present
    - name: Install python-virtualenv
      apt:
        name: python-virtualenv
        state: present
    - name: Install python-mysqldb
      apt:
        name: python-mysqldb
        state: present
---
- hosts: webserver
  become: true
  tasks:
    - name: Install web server packages
      apt:
        name: "{{ item }}"
        state: present
      loop:
        - apache2
        - libapache2-mod-wsgi
        - python-pip
        - python-virtualenv
        - python-mysqldb
        - virtualenv

Services

playbooks/loadbalancer.yml

Documentation

---
- hosts: loadbalancer
  become: true
  tasks:
    - name: Install nginx
      apt:
        name: nginx
        state: present
---
- hosts: loadbalancer
  become: true
  tasks:
    - name: Install nginx
      apt:
        name: nginx
        state: present

    - name: Ensure nginx service is started
      service:
        name: nginx
        state: started
        enabled: yes
ansible-playbook playbooks/loadbalancer.yml
wget -qO- http://johns-proxy01

curl Is Better

playbooks/control.yml

---
- hosts: control
  become: true
  tasks:
    - name: Install curl
      apt:
        name: curl
        state: present
ansible-playbook playbooks/control.yml
curl http://johns-proxy01

Give this a go:

  • Create a "control" playbook, which will apply to your ansible (local) machine.
    • In this playbook, include a task to install the package "curl".

Finishing Services

playbooks/webserver.yml

ansible-playbook playbooks/database.yml
ansible-playbook playbooks/webserver.yml
---
- hosts: webserver
  become: true
  tasks:
    - name: Install web server packages
      apt:
        name: "{{ item }}"
        state: present
      loop:
        - apache2
        - libapache2-mod-wsgi
        - python-pip
        - python-virtualenv

    - name: Ensure apache2 service is started
      service:
        name: apache2
        state: started
        enabled: yes
---
- hosts: database
  become: true
  tasks:
    - name: Install mysql-server
      apt:
        name: mysql-server
        state: present

    - name: Ensure mysql service is started
      service:
        name: mysql
        state: started
        enabled: yes

playbooks/database.yml

curl http://johns-web01
curl http://johns-web02

Apache2 Module

playbooks/webserver.yml

---
- hosts: webserver
  become: true
  tasks:
    - name: Install web server packages
      apt:
        name: "{{ item }}"
        state: present
      loop:
        - apache2
        - libapache2-mod-wsgi
        - python-pip
        - python-virtualenv

    - name: Ensure apache2 service is started
      service:
        name: apache2
        state: started
        enabled: yes

    - name: Ensure mod-wsgi module is enabled
      apache2_module:
        name: wsgi
        state: present

Documentation

Handlers

playbooks/webserver.yml

  tasks:
    - name: Ensure mod-wsgi module is enabled
      apache2_module:
        name: wsgi
        state: present

  handlers:
    - name: Restart apache2
      service:
        name: apache2
        state: restarted

Documentation

  tasks:
    - name: Ensure mod-wsgi module is enabled
      apache2_module:
        name: wsgi
        state: present
      notify: Restart apache2

  handlers:
    - name: Restart apache2
      service:
        name: apache2
        state: restarted
ansible-playbook playbooks/webserver.yml

Prepare Files

mkdir -p demo/app

demo/app/demo.wsgi

activate_this = '/var/www/demo/.venv/bin/activate_this.py'
execfile(activate_this, dict(__file__=activate_this))

import os
os.environ['DATABASE_URI'] = 'mysql://demo:demo@$IP_ADDRESS/demo'

import sys
sys.path.insert(0, '/var/www/demo')

from demo import app as application

demo/demo.conf

<VirtualHost *>
    WSGIDaemonProcess demo threads=5
    WSGIScriptAlias / /var/www/demo/demo.wsgi

    <Directory /var/www/demo>
        WSGIProcessGroup demo
        WSGIApplicationGroup %{GLOBAL}
        Order deny,allow
        Allow from all
    </Directory>
</VirtualHost>

demo/app/demo.py

from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
import os, socket

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = os.environ['DATABASE_URI']
db = SQLAlchemy(app)
hostname = socket.gethostname()

@app.route('/')
def index():
  return 'Hello, from sunny %s!\n' % hostname

@app.route('/db')
def dbtest():
  try:
      db.create_all()
  except Exception as e:
      return e.message + '\n'
  return 'Database Connected from %s!\n' % hostname

if __name__ == '__main__':
  app.run()

demo/app/requirements.txt

Flask==0.10.1
Flask-SQLAlchemy==2.0

Change the $IP_ADDRESS

Copy

playbooks/webserver.yml

Documentation

tasks:
  - name: Copy demo application source
    copy:
      src: ../demo/app/
      dest: /var/www/demo
      mode: 0755
    notify: Restart apache2
ansible-playbook playbooks/webserver.yml
tasks:
  - name: Copy demo application source
    copy:
      src: ../demo/app/
      dest: /var/www/demo
      mode: 0755
    notify: Restart apache2

  - name: Copy apache2 virtualhost configuration
    copy:
      src: ../demo/demo.conf
      dest: /etc/apache2/sites-available
      mode: 0755
    notify: Restart apache2

pip

playbooks/webserver.yml

Documentation

tasks:
  - name: Install python-pip dependencies
    pip:
      requirements: /var/www/demo/requirements.txt
      virtualenv: /var/www/demo/.venv
    notify: Restart apache2
ansible-playbook playbooks/webserver.yml

File

playbooks/webserver.yml

Documentation

tasks:
  - name: De-activate default apache site
    file:
      path: /etc/apache2/sites-enabled/000-default.conf
      state: absent
    notify: Restart apache2

  - name: Activate demo apache site
    file:
      src: /etc/apache2/sites-available/demo.conf
      dest: /etc/apache2/sites-enabled/demo.conf
      state: link
    notify: Restart apache2
ansible-playbook playbooks/webserver.yml
curl http://johns-web01
curl http://johns-web02
curl http://johns-proxy01

Jinja2 Templates

templates/nginx.conf.j2

Documentation

mkdir templates
vim templates/nginx.conf.j2
upstream demo {
    server johns-web01;
    server johns-web02;
}
server {
    listen 80;

    location / {
        proxy_pass http://demo;
    }
}
upstream demo {
{# Enter a server line for each host in the webservers group in Ansible #}
{% for server in groups.webserver %}
    server {{ server }};
{% endfor %}
}
server {
    listen 80;

    location / {
        proxy_pass http://demo;
    }
}

Template Module

playbooks/loadbalancer.yml

Documentation

---
tasks:
  - name: Configure nginx site
    template:
      src: ../templates/nginx.conf.j2
      dest: /etc/nginx/sites-available/demo
      mode: 0644
    notify: Restart nginx

  - name: De-activate default nginx site
    file:
      path: /etc/nginx/sites-enabled/default
      state: absent
    notify: Restart nginx

  - name: Activate demo nginx site
    file:
      src: /etc/nginx/sites-available/demo
      dest: /etc/nginx/sites-enabled/demo
      state: link
    notify: Restart nginx

handlers:
  - name: Restart nginx
    service:
      name: nginx
      state: restarted
ansible-playbook playbooks/loadbalancer.yml
curl http://johns-proxy01
#Run it a couple times!
---
tasks:
  - name: Configure nginx site
    template:
      src: ../templates/nginx.conf.j2
      dest: /etc/nginx/sites-available/demo
      mode: 0644
    notify: Restart nginx

  - name: De-activate default nginx site
    file:
      path: /etc/nginx/sites-enabled/default
      state: absent
    notify: Restart nginx

  - name: Activate demo nginx site
    file:
      src: /etc/nginx/sites-available/demo
      dest: /etc/nginx/sites-enabled/demo
      state: link
    notify: Restart nginx

handlers:
  - name: Restart nginx
    service:
      name: nginx
      state: restarted

lineinfile

playbooks/database.yml

ansible-playbook playbooks/database.yml
tasks:
  - name: Ensure mysql is listening on all addresses
    lineinfile:
      dest: /etc/mysql/mysql.conf.d/mysqld.cnf
      regexp: "^bind-address"
      line: "bind-address = 0.0.0.0"
    notify: Restart mysql

handlers:
  - name: Restart mysql
    service:
      name: mysql
      state: restarted

Documentation

ssh -t johns-database01 "grep -R bind-address /etc/mysql"
curl http://johns-app01/db
curl http://johns-proxy01/db

mysql_db

playbooks/database.yml

Documentation

ansible-playbook playbooks/database.yml
---
- hosts: database
  become: true
  tasks:
    - name: Install mysql-server
      apt:
        name: mysql-server
        state: present
        update_cache: yes
---
- hosts: database
  become: true
  tasks:
    - name: Install packages
      apt:
        name: "{{ item }}"
        state: present
        update_cache: yes
      loop:
        - mysql-server
        - python-mysqldb

Give this a go:

  • Modify the apt task in the database playbook to include the package "python-mysqldb" in the form of a loop.
    - name: Create demo database
      mysql_db:
        name: demo
        state: present

    - name: Create demo user
      mysql_user:
        name: demo
        password: demo
        priv: demo.*:ALL
        host: '%'
        state: present

curl http://johns-proxy01/db

It Lives!

Make It Right

What's Not Right?

  • One playbook for each tier
  • Playbooks specific to our site
  • What if another team wants to use our code?
    • How much code could they use for their site?
    • What about different port numbers?
  • How many teams do you have?
    • What if a vulnerability needs fixing for all teams?

Roles

  • A role is a folder structure where we function specific
    • Tasks
    • Handlers
    • Files
    • Templates
  • /etc/ansible/roles/$ROLE
  • Compose our infrastructure as a collection of roles
  • Allows for easier code reuse
  • Know where to look to make a change/fix an issue

Documentation

Creating Roles - galaxy init

Documentation

ansible-galaxy init roles/control
ansible-galaxy init roles/nginx

Give this a go:

  • Create skeleton roles for the rest of the infrastructure
ansible-galaxy init roles/control
ansible-galaxy init roles/nginx
ansible-galaxy init roles/apache2
ansible-galaxy init roles/mysql
ansible-galaxy init roles/demo_app

Importing Roles - Tasks

roles/control/tasks/main.yml

---
- name: Install curl
  apt:
    name: curl
    state: present

playbooks/control.yml

---
- hosts: control
  become: true
  tasks:
    - name: Install curl
      apt:
        name: curl
        state: present
---
- hosts: control
  become: true
  roles:
    - control

Importing Roles - Handlers

roles/mysql/tasks/main.yml

playbooks/database.yml

---
- hosts: database
  become: true
  roles:
    - mysql
---
- hosts: database
  become: true
  tasks:
    - name: Install packages
      ...
    
  handlers:
    - name: Restart mysql
      service:
        name: mysql
        state: restarted

roles/mysql/handlers/main.yml

---
- name: Restart mysql
  service:
    name: mysql
    state: restarted
---
- name: Install packages
  apt:
    name: "{{ item }}"
    state: present
  loop:
    - mysql-server
    - python-mysqldb

- name: Ensure mysql is listening on all addresses
  lineinfile:
    dest: /etc/mysql/mysql.conf.d/mysqld.cnf
    regexp: "^bind-address"
    line: "bind-address = 0.0.0.0"
  notify: Restart mysql

- name: Ensure mysql service is started
  service:
    name: mysql
    state: started
    enabled: yes

- name: Create demo database
  mysql_db:
    name: demo
    state: present

- name: Create demo user
  mysql_user:
    name: demo
    password: demo
    priv: demo.*:ALL
    host: '%'
    state: present

nginx Role

roles/nginx/tasks/main.yml

---
- name: Install nginx
  apt:
    name: nginx
    state: present

- name: Configure nginx site
  template:
    src: templates/nginx.conf.j2
    dest: /etc/nginx/sites-available/demo
    mode: 0644
  notify: Restart nginx

- name: De-activate default nginx site
  file:
    path: /etc/nginx/sites-enabled/default
    state: absent
  notify: Restart nginx

- name: Activate demo nginx site
  file:
    src: /etc/nginx/sites-available/demo
    dest: /etc/nginx/sites-enabled/demo
    state: link
  notify: Restart nginx

- name: Ensure nginx service is started
  service:
    name: nginx
    state: started
    enabled: yes

playbooks/loadbalancer.yml

---
- hosts: loadbalancer
  become: true
  roles:
    - nginx

roles/nginx/handlers/main.yml

---
- name: Restart nginx
  service:
    name: nginx
    state: restarted

Give this a go:

  • Import the loadbalancer playbook into a role
  • Modify the playbook file to include the new role

Importing Roles - Templates

roles/nginx/tasks/main.yml

- name: Configure nginx site
  template:
    src: ../templates/nginx.conf.j2
    dest: /etc/nginx/sites-available/demo
    mode: 0644
  notify: Restart nginx
- name: Configure nginx site
  template:
    src: nginx.conf.j2
    dest: /etc/nginx/sites-available/demo
    mode: 0644
  notify: Restart nginx
mv templates/nginx.conf.j2 roles/nginx/templates

apache2 Role

roles/apache2/tasks/main.yml

roles/demo_app/tasks/main.yml

- name: Install web server packages
  apt:
    name: "{{ item }}"
    state: present
  loop:
    - libapache2-mod-wsgi
    - python-pip
    - python-virtualenv
- name: Install web server packages
  apt:
    name: "{{ item }}"
    state: present
  loop:
    - apache2
- name: Ensure apache2 service is started
  service:
    name: apache2
    state: started
    enabled: yes
- name: Ensure mod-wsgi module is enabled
  apache2_module:
    name: wsgi
    state: present
  notify: Restart apache2
- name: Copy demo application source
  copy:
    src: demo/app/
    dest: /var/www/demo
    mode: 0755
  notify: Restart apache2

- name: Copy apache2 virtualhost configuration
  copy:
    src: demo/demo.conf
    dest: /etc/apache2/sites-available
    mode: 0755
  notify: Restart apache2

- name: Install python-pip dependencies
  pip:
    requirements: /var/www/demo/requirements.txt
    virtualenv: /var/www/demo/.venv
  notify: Restart apache2
- name: Activate demo apache site
  file:
    src: /etc/apache2/sites-available/demo.conf
    dest: /etc/apache2/sites-enabled/demo.conf
    state: link
  notify: Restart apache2
- name: De-activate default apache site
  file:
    path: /etc/apache2/sites-enabled/000-default.conf
    state: absent
  notify: Restart apache2

apache2 Role Continued

playbooks/webserver.yml

---
- hosts: webserver
  become: true
  roles:
    - apache2
    - demo_app

roles/apache2/handlers/main.yml

---
- name: Restart apache2
  service:
    name: apache2
    state: restarted

roles/demo_app/handlers/main.yml

---
- name: Restart apache2
  service:
    name: apache2
    state: restarted

Importing Roles - Files

mv demo/* roles/demo_app/files

roles/demo_app/tasks/main.yml

- name: Copy demo application source
  copy:
    src: app/
    dest: /var/www/demo
    mode: 0755
  notify: Restart apache2

- name: Copy apache2 virtualhost configuration
  copy:
    src: demo.conf
    dest: /etc/apache2/sites-available
    mode: 0755
  notify: Restart apache2

Site Playbook - Include

playbooks/site.yml

---
- hosts: control
  become: true
  roles:
    - control

- hosts: database
  become: true
  roles:
    - mysql

- hosts: loadbalancer
  become: true
  roles:
    - nginx

- hosts: webserver
  become: true
  roles:
    - apache2
    - demo_app

Documentation

ansible-playbook playbooks/site.yml
---
- import_playbook: database.yml
- import_playbook: webserver.yml
- import_playbook: loadbalancer.yml

Refactoring with Variables

Facts

roles/mysql/tasks/main.yml

- name: Ensure mysql is listening on all addresses
  lineinfile:
    dest: /etc/mysql/my.cnf
    regexp: "^bind-address"
    line: "bind-address = 0.0.0.0"
  notify: Restart mysql

Documentation

ansible -m setup john-database01
ansible-playbook playbooks/database.yml
- name: Ensure mysql is listening on all addresses
  lineinfile:
    dest: /etc/mysql/my.cnf
    regexp: "^bind-address"
    line: "bind-address = {{ ansible_default_ipv4.address }}"
  notify: Restart mysql

Role Defaults

roles/mysql/tasks/main.yml

- name: Create demo database
  mysql_db:
    name: demo
    state: present

- name: Create demo user
  mysql_user:
    name: demo
    password: demo
    priv: demo.*:ALL host='%'
    state: present

Documentation

- name: Create database
  mysql_db:
    name: demo
    state: present

- name: Create user
  mysql_user:
    name: demo
    password: demo
    priv: demo.*:ALL host='%'
    state: present
- name: Create database
  mysql_db:
    name: "{{ db_name }}"
    state: present

- name: Create user
  mysql_user:
    name: demo
    password: demo
    priv: "{{ db_name }}.*:ALL host='%'"
    state: present
- name: Create database
  mysql_db:
    name: "{{ db_name }}"
    state: present

- name: Create user
  mysql_user:
    name: "{{ db_user }}"
    password: "{{ db_password }}"
    priv: "{{ db_name }}.*:ALL"
    host: "{{ db_host }}"
    state: present

roles/mysql/defaults/main.yml

---
db_name: mydb
db_user: mydbuser
db_password: mydbpass
db_host: mydbhost

group_vars

Documentation

ansible-playbook playbooks/database.yml

group_vars/all/vars.yml

---
db_name: demo
db_user: demo
db_password: demo
db_host: "%"
mkdir -p group_vars/all
vim group_vars/all/vars.yml

group_vars - Continued

group_vars/all/vars.yml

---
db_name: demo
db_user: demo
db_password: demo
db_host: "%"
site_name: demo

Give this a go:

  • Replace the references to our site "demo" in the loadbalancer role with a variable:
    • Three references in the tasks file
    • Two references in the template
  • You can call the variable whatever you want to!
  • Remember to add definitions for this variable in group_vars
upstream {{ site_name }} {
{% for server in groups.webserver %}
    server {{ server }};
{% endfor %}
}
server {
    listen 80;

    location / {
        proxy_pass http://{{ site_name }};
    }
}
- name: Configure demo nginx site
  template:
    src: nginx.conf.j2
    dest: /etc/nginx/sites-available/demo
    mode: 0644
  notify: Restart nginx

- name: De-activate default nginx site
  file:
    path: /etc/nginx/sites-enabled/default
    state: absent
  notify: Restart nginx

- name: Activate demo nginx site
  file:
    src: /etc/nginx/sites-available/demo
    dest: /etc/nginx/sites-enabled/demo
    state: link
  notify: Restart nginx

roles/nginx/tasks/main.yml

- name: Configure nginx site
  template:
    src: nginx.conf.j2
    dest: "/etc/nginx/sites-available/{{ site_name }}"
    mode: 0644
  notify: Restart nginx

- name: De-activate default nginx site
  file:
    path: /etc/nginx/sites-enabled/default
    state: absent
  notify: Restart nginx

- name: Activate nginx site
  file:
    src: "/etc/nginx/sites-available/{{ site_name }}"
    dest: "/etc/nginx/sites-enabled/{{ site_name }}"
    state: link
  notify: Restart nginx

roles/nginx/templates/nginx.conf.j2

upstream demo {
{% for server in groups.webserver %}
    server {{ server }};
{% endfor %}
}
server {
    listen 80;

    location / {
        proxy_pass http://demo;
    }
}

ansible-vault

Documentation

ansible-vault create group_vars/all/vault.yml

group_vars/all/vault.yml

...
vault_password_file = ~/.ansible/.vault_password_file
...

~/.ansible_vault_password

really_super_secure_password_here

ansible.cfg

---
vault_db_password: demo

group_vars/all/vars.yml

---
db_name: demo
db_user: demo
db_password: "{{ vault_db_password }}"
db_host: "%"

Troubleshooting

Troubleshooting

--check (-C)/--diff (-D)

Documentation

  • "--check" does a dry run of the playbook (doesn't change anything).
    • Great for continuous integration checks before merging new code into master branch
  • "--diff" shows the difference in the configuration
    • Most effective when used with --check

--verbose (-v)

ansible-playbook playbooks/control.yml -vvvv
  • Simply shows more verbose output of the tasks as they are run.
  • More verbose output can be requested by adding extra "v" characters:
    • "-v" shows stdout and stderr
    • "-vv" does the same as -v (?)
    • "-vvv" shows the commands run by Ansible
    • "-vvvv" shows connection debugging

We're all done!

We're all done!

Extra Topics

  • Ansible Galaxy
  • Real world examples

Time Allowing

Ansible

By mwadman

Made with Slides.com

Ansible

An introduction to configuration and state management using Ansible.

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