ANSIBLE CHEAT SHEET Learn DevOps from experts at edureka.co
Ansible Architecture
Inventory Files & Hosts Patterns
Ad-Hoc Commands
SSH Key Generation & Install Ansible
What is Ansible?
ungrouped.example.com #An ungrouped host
[webservers] #A group called webservers
beta.example.com ansible_host = 10.0.0.5 #ssh to 10.0.0.5
github.example.com ansible_ssh_user = abc #ssh as user abc
[clouds]
cloud.example.com fileuser = alice #fileuser is a host variable
[moscow]
beta.example.com #Host (DNS will resolve)
telecom.example.com #Host(DNS will resolve)
[dev1:children] #dev1 is a group containing
webservers #All hosts in group webservers
clouds #All hosts in group clouds
Playbooks
#Add Ansible repository
$sudo apt-add-repository ppa:ansible/ansible
#Run the update command
$sudo apt-get update
#Install Ansible package
$sudo apt-get install ansible
#Check Ansible Version
$ ansible –version
Ansible uses SSH to communicate between the nodes.
SSH Key Generation
Install Ansible
To install Ansible in Debian Linux, follow the following steps:
#Setting Up SSH Command
$ sudo apt-get install openssh-server
#Generating SSH Key
$ ssh-keygen
#Copy the SSH Key on the Hosts
$ ssh-copy-id hostname
#Check the SSH Connection
$ ssh <nodeName>
Ansible’s inventory lists all the platforms you want to automate across. Ansible can at a single instance work on multiple hosts in the
infrastructure.
Setup & Hosts Connection
#Set up hosts by editing the hosts' file in the Ansible directory
$sudo nano /etc/ansible/hosts
#To check the connection to hosts
#First change the directory to /etc/Ansible
$ cd /etc/ansible
#To check whether Ansible is connecting to hosts, use ping command
$ ansible –m ping <hosts>
#To check on servers individually
$ ansible -m ping server name
#To check a particular server group
$ ansible -m ping servergroupname
Follow the below steps to set hosts and then check their connection.
Ansible Hosts Patterns
The below is an example inventory file, which you can refer to understand the various parameters.
Parallelism & Shell Commands
Ad-Hoc commands are quick commands which are used to perform the actions, that won’t be saved for later.
#To set up SSH agent
$ ssh-agent bash $ ssh-add ~/.ssh/id_rsa
#To use SSH with a password instead of keys, you can use --ask-pass (-K)
$ ansible europe -a "/sbin/reboot" -f 20
#To run /usr/bin/ansible from a user account, not the root
$ ansible europe -a "/usr/bin/foo" -u username
#To run commands through privilege escalation and not through user account
$ ansible europe -a "/usr/bin/foo" -u username --become [--ask-become-pass]
#If you are using password less method then use --ask-become-pass (-K) to interactively get the password to be use
#You can become a user, other than root by using --become-user
$ ansible europe -a "/usr/bin/foo" -u username --become --become-user otheruser [--ask-become-pass]
File Transfer
#Transfer a file directly to many servers
$ ansible europe -m copy -a "src=/etc/hosts dest=/tmp/hosts"
#To change the ownership and permissions on files
$ ansible webservers -m file -a "dest=/srv/foo/a.txt mode=600" $ ansible webservers -m file -a "dest=/srv/foo/b.txt
mode=600 owner=example group=example"
#To create directories
$ ansible webservers -m file -a "dest=/path/to/c mode=755 owner=example group=example state=directory“
#To delete directories (recursively) and delete files
$ ansible webservers -m file -a "dest=/path/to/c state=absent
Manage Packages
#To ensure that a package is installed, but doesn’t get updated
$ ansible webservers -m apt -a "name=acme state=present"
#To ensure that a package is installed to a specific version
$ ansible webservers -m apt -a "name=acme-1.5 state=present"
#To ensure that a package at the latest version
$ ansible webservers -m apt -a "name=acme state=latest"
#To ensure that a package is not installed
$ ansible webservers -m apt -a "name=acme state=absent
Manage Services
#To ensure a service is started on all web servers
$ ansible webservers -m service -a "name=httpd
state=started"
#To restart a service on all web servers
$ ansible webservers -m service -a "name=httpd
state=restarted"
#To ensure a service is stopped
$ ansible webservers -m service -a "name=httpd
state=stopped
Sample Playbooks
#Every YAML file starts with ---
---
- hosts: webservers
vars: http_port: 80
max_clients: 200
remote_user: root
tasks:
-name: ensure apache is at the latest version
apt: name=httpd state=latest
-name: write the apache config file
template: src=/srv/httpd.j2 dest=/etc/httpd.conf
notify: -
-restart apache
-name: ensure apache is running (and enable it at boot)
service: name=httpd state=started enabled=yes
handlers:
-name: restart apache
service: name=httpd state=restarted
Writing Playbooks
#Generate the SSH Key and connect hosts to control
machine before writing and running playbooks.
#Create a Playbook
$vi <name of your file>.yml
#To write the playbook refer to the snapshot here.
#Run the playbook
$ ansible-playbook <name of your file>.yml
Deploying From Source Control
#GitRep:https://foo.example.org/repo.git #Destination:/src/myapp
$ ansible webservers -m git -a "repo=https://foo.example.org/repo.git dest=/src/myapp version=HEAD"
Ansible is a continuous deployment and
configuration tool which provides large productivity
gains to a wide variety of automation challenges.
DEVOPS
CERTIFICATION
TRAINING
Ansible Hosts Patterns
all All hosts in inventory
* All hosts in inventory
ungrouped All hosts in inventory not appearing within a group
10.0.0.* All hosts with an IP starting 10.0.0.*
webservers The group webservers
webservers:!moscow Only hosts in webservers, not also in group
moscow
webservers:&moscow Only hosts in the group’s webservers and moscow
INVENTORY API
PLUGINS
HOST
Network
MODULES
Example Inventory File
