Ansible lamp stack contd..
- Lamp stack playbook for yaml
---
- name: 'Install and configure lamp'
hosts: ubuntu
become: yes
tasks:
- name: install apache2 and update ubuntu package definitions
apt:
name: apache2
update_cache: yes
state: present
- name: enable and start apache2
service:
name: apache2
enabled: yes
state: started
- name: install php
apt:
name: php
state: present
- name: install libapache2-mod-php
apt:
name: libapache2-mod-php
state: present
- name: install php-mysql
apt:
name: php-mysql
state: present
- name: install php-cli
apt:
name: php-cli
state: present
- name: restart apache
service:
name: apache2
state: restarted
- Lamp stack playbook for centos
---
- name: install lamp stack on Centos
become: yes
hosts: centos
tasks:
- name: install apache
yum:
name: httpd
state: present
- name: start and enable apache
service:
name: httpd
enabled: yes
state: started
- name: install php
yum:
name: php
state: present
- name: install php-mysql
yum:
name: php-mysql
state: present
- name: install php-fpm
yum:
name: php-fpm
state: present
- name: restart apache
service:
name: httpd
state: restarted
- For installing php modules we have used the same task with different values. consider the below statement
# repeating statements
print(1)
print(2)
print(3)
print(4)
# using loops
for index in range(1,4):
print(index)
- Now we need to find out if the loops are supported by ansible and if yes how? Refer Here for ansible documentation
- name: add several users
user:
name: "{{ item }}"
state: present
groups: "wheel"
loop:
- testuser1
- testuser2
- The above example is equivalent to
- name: add testuser1
user:
name: testuser1
state: present
group: wheel
- name: add testuser2
user:
name: testuser2
state: present
group: wheel
- Consider the following lines in centos yaml
- name: install php
yum:
name: php
state: present
- name: install php-mysql
yum:
name: php-mysql
state: present
- name: install php-fpm
yum:
name: php-fpm
state: present
- These can be replaced with
- name: install php packages
yum:
name: "{{ item }}"
state: present
loop:
- php
- php-mysql
- php-fpm
- If the similar concept is applied to ubuntu.yaml
- name: install php packages
apt:
name: "{{ item }}"
state: present
loop:
- php
- libapache2-mod-php
- php-mysql
- php-cli
- By adopting above changes our lamp_centos.yaml will be
---
- name: install lamp stack on Centos
become: yes
hosts: centos
tasks:
- name: install apache
yum:
name: httpd
state: present
- name: start and enable apache
service:
name: httpd
enabled: yes
state: started
- name: install php packages
yum:
name: "{{ item }}"
state: present
loop:
- php
- php-mysql
- php-fpm
- name: restart apache
service:
name: httpd
state: restarted
- lamp_ubuntu.yaml will be looking as shown below
---
- name: 'Install and configure lamp'
hosts: ubuntu
become: yes
tasks:
- name: install apache2 and update ubuntu package definitions
apt:
name: apache2
update_cache: yes
state: present
- name: enable and start apache2
service:
name: apache2
enabled: yes
state: started
- name: install php packages
apt:
name: "{{ item }}"
state: present
loop:
- php
- libapache2-mod-php
- php-mysql
- php-cli
- name: restart apache
service:
name: apache2
state: restarted
- Now execute these playbooks to verify if they are working or not
- Do i really need two files, cant i write something like
if node is centos
execute the centos tasks
else if node is ubuntu
execute the ubuntu tasks
- How to find if the node is ubuntu or centos?
- Ansible has concept of gathering a facts. Facts are information about nodes. facts can be collected by using a module called as setup. Refer Here
- Execute the following commands
ansible -i hosts -m setup centos
ansible -i hosts -m setup ubuntu
- Lets evaluate playbook vs adhoc command
- name: testing
setup:
filter: "*distribution*"
ansible -m setup -a "filter=*distribution*" all
- So now we have some thing to verify or use as condition in playbook. For centos machine the value of ansible_distribution is "Centos" and for ubuntu node the value is "Ubuntu"
if ansible_distribution == "Centos"
run centos tasks
else if ansible_distribution == "Ubuntu"
run ubuntu tasks
- For ansible conditionals refer here
- IF the fact name is ansible_something this can be used in playbook as ansible_facts[‘something’]. our key is ansible_distribution so we will be using ansible_facts[‘distribution’]
- name: "shut down Debian flavored systems"
command: /sbin/shutdown -t now
when: ansible_facts['os_family'] == "Debian"
- Our resulting playbook with combined yaml files will be
---
- name: install apache
hosts: all
become: yes
tasks:
- name: install httpd
yum:
name: httpd
state: present
when: ansible_facts['distribution'] == "CentOS"
- name: start and enable httpd
service:
name: httpd
enabled: yes
state: started
when: ansible_facts['distribution'] == "CentOS"
- name: install php packages httpd
yum:
name: "{{ item }}"
state: present
loop:
- php
- php-mysql
- php-fpm
when: ansible_facts['distribution'] == "CentOS"
- name: restart httpd
service:
name: httpd
state: restarted
when: ansible_facts['distribution'] == "CentOS"
- name: install apache2 and update ubuntu package definitions
apt:
name: apache2
update_cache: yes
state: present
when: ansible_facts['distribution'] == "Ubuntu"
- name: enable and start apache2
service:
name: apache2
enabled: yes
state: started
when: ansible_facts['distribution'] == "Ubuntu"
- name: install php packages
apt:
name: "{{ item }}"
state: present
loop:
- php
- libapache2-mod-php
- php-mysql
- php-cli
when: ansible_facts['distribution'] == "Ubuntu"
- name: restart apache
service:
name: apache2
state: restarted
when: ansible_facts['distribution'] == "Ubuntu"
- Now lets execute the playbook
ansible-playbook -i hosts lamp.yaml
- In ansible there is a generic module called as package.
- This module when executed on centos will execute yum & when executed on ubuntu machines will execute apt-get, so shall we use this module
---
- name: install apache
hosts: all
become: yes
tasks:
- name: install httpd
package:
name: httpd
state: present
when: ansible_facts['distribution'] == "CentOS"
- name: start and enable httpd
service:
name: httpd
enabled: yes
state: started
when: ansible_facts['distribution'] == "CentOS"
- name: install php packages httpd
package:
name: "{{ item }}"
state: present
loop:
- php
- php-mysql
- php-fpm
when: ansible_facts['distribution'] == "CentOS"
- name: restart httpd
service:
name: httpd
state: restarted
when: ansible_facts['distribution'] == "CentOS"
- name: update Ubuntu packages
apt:
update_cache: yes
when: ansible_facts['distribution'] == "Ubuntu"
- name: install apache2
package:
name: apache2
state: present
when: ansible_facts['distribution'] == "Ubuntu"
- name: enable and start apache2
service:
name: apache2
enabled: yes
state: started
when: ansible_facts['distribution'] == "Ubuntu"
- name: install php packages
package:
name: "{{ item }}"
state: present
loop:
- php
- libapache2-mod-php
- php-mysql
- php-cli
when: ansible_facts['distribution'] == "Ubuntu"
- name: restart apache
service:
name: apache2
state: restarted
when: ansible_facts['distribution'] == "Ubuntu"
- Now executing this will get the same results
- But in our playbook we use different package task for ubuntu and centos. Cant we use one package task rather than two package tasks?. What is difference in
- name: install httpd
package:
name: httpd
state: present
when: ansible_facts['distribution'] == "CentOS"
- name: install apache2
package:
name: apache2
state: present
when: ansible_facts['distribution'] == "Ubuntu"
- Lets compare the above statements to
if machine is ubuntu
print("ubuntu")
else if machine is centos
print("centos")
or
def print_message(message):
print(message)
- To achieve this we need to use variable message. So lets see if ansible supports variables. Refer Here
Summary
- Today we have introduced
- Looping statements using loop
- conditional statements using when
- information about nodes using facts and setup module
- We have discussed about generic os packager module package
