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Training/Hands on to create ansible

  1. vagrant ssh acs 1.mkdir exercise1; cd exercise1

Create Inventory Compoenent

  1. vi inventory

Basic Ansible Command

ansible -i -m -u -k -v (-vv debug level2/ -vvv debug level3)

Add the ip of the web server and db server

  1. 192.168.33.20 , 192.168.33.33

  2. ping the ip. eg ansible 192.168.33.20 -i inventory -u vagrant -m ping -k ansible all -i inventory -u vagrant -m ping -k ansible all -i inventory -u vagrant -m ping -k -vvv

    ansible all -i inventory -u vagrant -m command -a "/sbin/reboot" ansible all -i inventory -u vagrant -m command -a "/usr/sbin/yum update -y" or ansible all -i inventory -u vagrant -m -a "/usr/sbin/yum update -y"

  3. Module has 2 types : command(run a python executable) and shell (can use shell variable)

Inventory Fundamentals

  1. Inventory Features - Behavioral parameters, Groups, Groups of Groups, Assign Variables, Scaling out using multiple files, Static/Dynamic Inventory File

Example of Inventory File

web1 ansible_ssh_host=192.168.33.20 ansible_ssh_user=vagrant ansible_ssh_pass=vagrant

run ansible web1 -i inventory -m ping

Setting Group

web1 ansible_ssh_host=192.168.33.20 ansible_ssh_user=vagrant ansible_ssh_pass=vagrant db1 ansible_ssh_host=192.168.33.30 ansible_ssh_user=vagrant ansible_ssh_pass=vagrant

[webservers] web1 db1

Setting with Group of Groups

web1 ansible_ssh_host=192.168.33.20 ansible_ssh_user=vagrant ansible_ssh_pass=vagrant db1 ansible_ssh_host=192.168.33.30 ansible_ssh_user=vagrant ansible_ssh_pass=vagrant

[webservers] web1

[dbservers] db1

[datacenter:children] webservers dbservers

run command ansible datacenter -i inventory -m ping

Sharing variables

web1 ansible_ssh_host=192.168.33.20 db1 ansible_ssh_host=192.168.33.30

[webservers] web1

[dbservers] db1

[datacenter:children] webservers dbservers

[datacenter:vars] ansible_ssh_user=vagrant ansible_ssh_pass=vagrant

run command ansible datacenter -i inventory -m ping

Scaling out with Multiple Files

Using directories to manage

|__production | | | |--------group_vars | | \all | | \db | |--------host_vars | | \web1 | |--------inventory_prod |__test | | | |--------group_vars | | \all | | \db | |--------host_vars | | \web1 | |--------inventory+test

Order of Operations (Precedence)

  1. Group_Vars - All
  2. Group_Vars - GroupName
  3. Host_Vars Hostname (The highest precedence)

--The most specific version of that variable is actually going to take the highest level of precedence.

-- variable files are written in YAML file

Eg of variable file

file : group_vars/dc1-west

ntp: ntp-west.company.com syslog: logger-west-company.com

Demo : Scaling out with Multiple Files

Create the group variable username in the group_vars file

run command ansible webservers -i inventory_prod -m user -a "name={{username}} password=12345" --sudo

Ansible Configuration

To configure fingerprint for ssh

  1. touch ansible.cfg
  2. [defaults] host_key_checking=False
  3. ansible web1 -i inventory_prod -m ping

Ansible Environment Variable Takes Precedence over Ansible Configuration

  1. export ANSIBLE_HOST_KEY_CHECKING=True
  2. ansible web1 -i inventory_prod -m ping

Ansible Modules.

There are 3 kinds of modules : Core, Extras and Deprecated

  1. To list modile run ansible-doc -l
  2. To list modile run ansible-doc -s
  3. To list modile run ansible-doc

Copy Module

Copies a file from local box to remote system Has "backup" capability Can do validation remotely

Fetch Module

Pulls a file from remote host to local system Can use md5 checksums to validate

Apt Module

Manages installed applications on Debian-based systems Can install, update or delete packages Can update entire system

Yum Module

Manages installed applications on Redhat-based systems Can install, update or delete packages Can update entire system

Service Module

Can stop, start and restart services Can enable services to start on boot

Demo: Using Modules to Install/Start

  • Browse module documentation
  • Install Web Server(Yum module)
  • Start Web Server(Service module)
  • Install db server(Yum module)
  • Start db server(Service module)
  • Stop firewalls (Service module)

Install Web Server(Yum module)

run command ansible webservers -i inventory -m yum -a "name=httpd state=present" --sudo

Start Web Server(Service module)

run command ansible webservers -i inventory -m service -a "name=httpd enabled=yes state=started" --sudo

Install db server(Yum module)

run command ansible dbservers -i inventory -m yum -a "name=mysql-server state=present" --sudo

check the db state. run command service mysqld status

Start db server(Service module)

ansible dbservers -i inventory -m service -a "name=mysqld state=started" --sudo

Stop firewalls (Service module)

  1. Browse http://192.168.33.20/
  2. run command to stop firewall ansible webservers:dbservers -i inventory -m service -a "name=iptables state=stopped" --sudo

Host/Group Target Patterns

  1. OR (group1:group2)_
  2. NOT (!group2)
  3. Wildcard (web*.ex.com)
  4. Regex (~web[0-9]+)
  5. Complex Patterns AND (group1:&group2). Specific for intersection

Demo: Using Setup Module

  • Gather facts on remote systems
  • Used in Playbooks
  1. run command ansible web1 -i inventory -m setup
  2. run command ansible web1 -i inventory -m setup -a "filter=ansible_eth*"
  3. run command ansible web1 -i inventory -m setup -a "filter=ansible_mounts"
  4. run command ansible all -i inventory -m setup --tree ./setup

Plays and Playbooks

Plays map hosts to tasks A play can have multiple tasks A playbook can have multiple plays

  1. run command to execute playbook ansible-playbook playbook.yml

Example

refer to example.yml

Demo: Basic Playbook

  • Write a playbook
  • Add play to install web server
  • Add play to install db server
  • Add play to start services
  • Fail a play
  • Retry a failed play
  1. Create ansible.cfg. Refer to PlaybookDemo/ansible.cfg
  2. run command ansible-playbook web_db.yml
  3. in the case of failure can just rerun the fail case eg: run command ansible-playbook web_db.yaml --limit @/home/vagrant/web_db.yaml.retry
  • Templates
    • Creates and copies dynamic files
    • Uses Jinja2 Engine

Demo: Advanceed Playbook Usage