The Power of Jinja2 Templates

Kamen Tarlov Middleware Engineer and co-founder

Agenda• About Me

• Introduction to Jinja2 Templates

• Jinja2 IF and Loop Statements

• Jinja2 Template Skeleton

• Ansible and Jinja2 in action

• Questions and Answers

• Middleware Engineer and co-founder

• Experience with MW Technologies and Configuration Management

• Ansible, Puppet ..

• Openstack

About Me

Introduction to Jinja2 templates• Why do we need templates?

• Library for Python and Django

• Jinja2 works with Python 2.6.x, 2.7.x and >= 3.3

• easy_install Jinja2

• pip install Jinja2

• Out of the box with Ansible

• File Extension – j2: sample.j2

• Variables in {{ var }}

• Statements in {% if/for %}

• Optimised performance

Jinja2 Template Skeleton{% for vhost in apache_vhosts %}<VirtualHost *:80> ServerName {{ vhost.servername }} DocumentRoot {{ vhost.documentroot }}{% if vhost.serveradmin is defined %} ServerAdmin {{ vhost.serveradmin }}{% endif %} <Directory "{{ vhost.documentroot }}"> AllowOverride All Order allow,deny Allow from all </Directory></VirtualHost>{% endfor %}

IF STATEMENT

LOOP

VARIABLE

Variables in Ansible

• Variables defined in configuration file

• Yaml Format

• Flexible

• Supports Arrays

vars: apache_vhosts: - {servername: “demojinja2.itgix.com", documentroot: "/www/domain"} - {servername: " demojinja3.itgix.com ", documentroot: "/www/otherdomain", serveradmin: "webmaster@otherdomain.tld"}

ANSIBLE PLAYBOOK ---- - hosts: all user: centos sudo: true tasks: - include_vars: './apache_vhosts.yaml' - name: ensure apache is installed yum: name=httpd state=present - name: make sure apache is running action: service name=httpd state=started enabled=true - name: add template to configuration directory template: 'src=./01-vhost.conf.j2 dest=/etc/httpd/conf.d/01-vhost.conf owner=apache group=apache mode=0755' - name: create document root directories file: path={{ item.documentroot }} state=directory owner=apache group=apache mode=0755 with_items: '{{ apache_vhosts }}' - name: upload index files template: 'src=./{{ item.servername }}.j2 dest=/var/www/html/{{ item.servername }}/index.html owner=apache group=apache mode=0755' with_items: '{{ apache_vhosts }}' - name: restart ansible service service: name=httpd state=restarted

Ansible and Jinja2 in action

THANK YOU!