Playbook Example
In here I will examile a real use case example by creating and executing Ansible playbooks. I will install Nginx in all hosts and explore the different options for targeting OS variations with Ansible packages.
Use Ansible to install and configure project website, taking into account variances between the linux distributions of Nginx on both CentOS and Ubuntu.
Use Jinja2 templates to customise the website.
Let's first create our ansible config file ansible.cfg:
[defaults]
inventory = hosts
host_key_checking = FalseNext our group vars for centos and ubuntu hosts:
group_vars/centos:
---
ansible_user: root
...group_vars/ubuntu:
---
ansible_user: root
...Next our host file hosts:
[control]
ubuntu-c
[centos]
centos[1:3]
[ubuntu]
ubuntu[1:3]
[linux:children]
centos
ubuntuNext our playbook itself for installing EPEL on CentOS hosts:
---
# YAML documents begin with the document separator ---
# The minus in YAML this indicates a list item. The playbook contains a list
# of plays, with each play being a dictionary
-
# Hosts: where our play will run and options it will run with
hosts: linux
# Vars: variables that will apply to the play, on all target systems
# Tasks: the list of tasks that will be executed within the play, this section
# can also be used for pre and post tasks
tasks:
- name: Install EPEL
yum:
name: epel-release
update_cache: yes
state: latest
when: ansible_distribution == 'CentOS'
# Handlers: the list of handlers that are executed as a notify key from a task
# Three dots indicate the end of a YAML document
...Now we can execute the playbook:
$ ansible-playbook nginx_playbook.yaml
PLAY [linux] *****************************************************************************************************************
TASK [Gathering Facts] ******************************************************************************************************************************
ok: [centos2]
ok: [centos1]
ok: [centos3]
ok: [ubuntu1]
ok: [ubuntu2]
ok: [ubuntu3]
TASK [Install EPEL] ******************************************************************************************************************************
skipping: [ubuntu1]
skipping: [ubuntu2]
skipping: [ubuntu3]
changed: [centos1]
changed: [centos3]
changed: [centos2]
PLAY RECAP *******************************************************************************************************************
centos1 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
centos2 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
centos3 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
ubuntu1 : ok=1 changed=0 unreachable=0 failed=0 skipped=1 rescued=0 ignored=0
ubuntu2 : ok=1 changed=0 unreachable=0 failed=0 skipped=1 rescued=0 ignored=0
ubuntu3 : ok=1 changed=0 unreachable=0 failed=0 skipped=1 rescued=0 ignored=0Now let's install Nginx in all hosts by slightly modifying the playbook nginx_playbook.yaml:
---
# YAML documents begin with the document separator ---
# The minus in YAML this indicates a list item. The playbook contains a list
# of plays, with each play being a dictionary
-
# Hosts: where our play will run and options it will run with
hosts: linux
# Vars: variables that will apply to the play, on all target systems
# Tasks: the list of tasks that will be executed within the play, this section
# can also be used for pre and post tasks
tasks:
- name: Install EPEL
yum:
name: epel-release
update_cache: yes
state: latest
when: ansible_distribution == 'CentOS'
- name: Install Nginx CentOS
yum:
name: nginx
update_cache: yes
state: latest
when: ansible_distribution == 'CentOS'
- name: Install Nginx Ubuntu
apt:
name: nginx
update_cache: yes
state: latest
when: ansible_distribution == 'Ubuntu'
# Handlers: the list of handlers that are executed as a notify key from a task
# Three dots indicate the end of a YAML document
...Once we execute it, the output should be something similar to below:
$ ansible-playbook nginx_playbook.yaml
PLAY RECAP *******************************************************************************************************************
centos1 : ok=3 changed=2 unreachable=0 failed=0 skipped=1 rescued=0 ignored=0
centos2 : ok=3 changed=2 unreachable=0 failed=0 skipped=1 rescued=0 ignored=0
centos3 : ok=3 changed=2 unreachable=0 failed=0 skipped=1 rescued=0 ignored=0
ubuntu1 : ok=2 changed=1 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0
ubuntu2 : ok=2 changed=1 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0
ubuntu3 : ok=2 changed=1 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0or we can simply use Nginx module for that like below in nginx_playbook.yaml:
---
# YAML documents begin with the document separator ---
# The minus in YAML this indicates a list item. The playbook contains a list
# of plays, with each play being a dictionary
-
# Hosts: where our play will run and options it will run with
hosts: linux
# Vars: variables that will apply to the play, on all target systems
# Tasks: the list of tasks that will be executed within the play, this section
# can also be used for pre and post tasks
tasks:
- name: Install EPEL
yum:
name: epel-release
update_cache: yes
state: latest
when: ansible_distribution == 'CentOS'
- name: Install Nginx
package:
name: nginx
state: latest
# Handlers: the list of handlers that are executed as a notify key from a task
# Three dots indicate the end of a YAML document
...Next let's add a task to restart Nginx in our playbook:
---
# YAML documents begin with the document separator ---
# The minus in YAML this indicates a list item. The playbook contains a list
# of plays, with each play being a dictionary
-
# Hosts: where our play will run and options it will run with
hosts: linux
# Vars: variables that will apply to the play, on all target systems
# Tasks: the list of tasks that will be executed within the play, this section
# can also be used for pre and post tasks
tasks:
- name: Install EPEL
yum:
name: epel-release
update_cache: yes
state: latest
when: ansible_distribution == 'CentOS'
- name: Install Nginx
package:
name: nginx
state: latest
- name: Restart nginx
service:
name: nginx
state: restarted
# Handlers: the list of handlers that are executed as a notify key from a task
# Three dots indicate the end of a YAML document
...Now let's had a handler to add a http health check to make sure Nginx is running:
---
# YAML documents begin with the document separator ---
# The minus in YAML this indicates a list item. The playbook contains a list
# of plays, with each play being a dictionary
-
# Hosts: where our play will run and options it will run with
hosts: linux
# Vars: variables that will apply to the play, on all target systems
# Tasks: the list of tasks that will be executed within the play, this section
# can also be used for pre and post tasks
tasks:
- name: Install EPEL
yum:
name: epel-release
update_cache: yes
state: latest
when: ansible_distribution == 'CentOS'
- name: Install Nginx
package:
name: nginx
state: latest
- name: Restart nginx
service:
name: nginx
state: restarted
notify: Check HTTP Service
# Handlers: the list of handlers that are executed as a notify key from a task
handlers:
- name: Check HTTP Service
uri:
url: http://{{ ansible_default_ipv4.address }}
status_code: 200
# Three dots indicate the end of a YAML document
...Next let's create group vars for HTML location for Nginx in different hosts, and create a jinja template for HTML.
First let's nodify the playbook to deploy the HTML file inside Nginx:
---
# YAML documents begin with the document separator ---
# The minus in YAML this indicates a list item. The playbook contains a list
# of plays, with each play being a dictionary
-
# Hosts: where our play will run and options it will run with
hosts: linux
# Vars: variables that will apply to the play, on all target systems
# Tasks: the list of tasks that will be executed within the play, this section
# can also be used for pre and post tasks
tasks:
- name: Install EPEL
yum:
name: epel-release
update_cache: yes
state: latest
when: ansible_distribution == 'CentOS'
- name: Install Nginx
package:
name: nginx
state: latest
- name: Restart nginx
service:
name: nginx
state: restarted
notify: Check HTTP Service
- name: Template index.html-base.j2 to index.html on target
template:
src: index.html-base.j2
dest: "{{ nginx_root_location }}/index.html"
mode: 0644
# Handlers: the list of handlers that are executed as a notify key from a task
handlers:
- name: Check HTTP Service
uri:
url: http://{{ ansible_default_ipv4.address }}
status_code: 200
# Three dots indicate the end of a YAML document
...Next our group vars for centos and ubuntu hosts:
group_vars/centos:
---
ansible_user: root
nginx_root_location: /usr/share/nginx/html
...group_vars/ubuntu:
---
ansible_user: root
nginx_root_location: /var/www/html
...Now let's add the ansible_managed variable in the ansible.cfg:
[defaults]
inventory = hosts
host_key_checking = False
ansible_managed = Managed by Ansible - file:{file} - host:{host} - uid:{uid}Now we can use the ansible_managed variable inside any of our templates.
Now let's load out variables in the playbook.
---
# YAML documents begin with the document separator ---
# The minus in YAML this indicates a list item. The playbook contains a list
# of plays, with each play being a dictionary
-
# Hosts: where our play will run and options it will run with
hosts: linux
# Vars: variables that will apply to the play, on all target systems
vars_files:
- vars/logos.yaml
# Tasks: the list of tasks that will be executed within the play, this section
# can also be used for pre and post tasks
tasks:
- name: Install EPEL
yum:
name: epel-release
update_cache: yes
state: latest
when: ansible_distribution == 'CentOS'
- name: Install Nginx
package:
name: nginx
state: latest
- name: Restart nginx
service:
name: nginx
state: restarted
notify: Check HTTP Service
- name: Template index.html-logos.j2 to index.html on target
template:
src: index.html-logos.j2
dest: "{{ nginx_root_location }}/index.html"
mode: 0644
# Handlers: the list of handlers that are executed as a notify key from a task
handlers:
- name: Check HTTP Service
uri:
url: http://{{ ansible_default_ipv4.address }}
status_code: 200
# Three dots indicate the end of a YAML document
...Add unarchive task in the playbook to unarchive the code of our hidden game.
- name: Unarchive playbook stacker game
unarchive:
src: playbook_stacker.zip
dest: "{{ nginx_root_location }}"
mode: 0755Last updated