terça-feira, 3 de janeiro de 2017

Automating Infrastructure on Premise or Cloud with Ansible

Ansible Tasks are idempotent. Without a lot of extra coding, bash scripts are usually not safety run again and again. Ansible uses "Facts", which is system and environment information it gathers ("context") before running Tasks.

Design Principles

  • Have a dead simple setup process and a minimal learning curve
  • Manage machines very quickly and in parallel
  • Avoid custom-agents and additional open ports, be agentless by leveraging the existing SSH daemon
  • Describe infrastructure in a language that is both machine and human friendly
  • Focus on security and easy auditability/review/rewriting of content
  • Manage new remote machines instantly, without bootstrapping any software
  • Allow module development in any dynamic language, not just Python
  • Be usable as non-root
  • Be the easiest IT automation system to use, ever.

Ansible by default manages machines over the SSH protocol.

Once Ansible is installed, it will not add a database, and there will be no daemons to start or keep running. You only need to install it on one machine (which could easily be a laptop) and it can manage an entire fleet of remote machines from that central point. When Ansible manages remote machines, it does not leave software installed or running on them, so there’s no real question about how to upgrade Ansible when moving to a new version.

Playbooks could be considered the main concept in Ansible.

Playbooks are Ansible’s configuration, deployment, and orchestration language. They can describe a policy you want your remote systems to enforce, or a set of steps in a general IT process.

At a basic level, playbooks can be used to manage configurations of and deployments to remote machines. At a more advanced level, they can sequence multi-tier rollouts involving rolling updates, and can delegate actions to other hosts, interacting with monitoring servers and load balancers along the way.

Playbooks are designed to be human-readable and are developed in a basic text language.

Playbooks are expressed in YAML format and have a syntax, which intentionally tries to not be a programming language or script, but rather a model of a configuration or a process.

In my example, set two virtual machines with Vagrant, where the first I put Ansible installed and the second I applied some configurations.


Configure multi-machine like this in my previous post

Vagrantfile to multi-machine:

 Vagrant.configure(2) do |config|  
  config.vm.box = "ubuntu/trusty64"  
  config.vm.define "machine1" do |node1|  
    node1.vm.network "private_network", ip: "192.168.0.101"  
    node1.vm.hostname = "machine1"  
    node1.vm.provider "virtualbox" do |v|  
     v.memory = 1024  
     v.cpus = 1  
   end  
  end  
  config.vm.define "machine2" do |node2|  
    node2.vm.network "private_network", ip: "192.168.0.102"  
    node2.vm.hostname = "machine2"  
    node2.vm.provider "virtualbox" do |v|  
     v.memory = 1024  
     v.cpus = 1  
   end  
  end  
 end  

On machine1 install Ansible with these commands below:

#vagrant ssh machine1

If ask for password put “vagrant"

Commands to Install Ansible:

  1.  sudo apt-get install software-properties-common
  2.  sudo apt-add-repository ppa:ansible/ansible
  3.  sudo apt-get update
  4.  sudo apt-get install ansible

Edit /etc/ansible/hosts  and add IPs (192.168.0.101 , 192.168.0.102)

To check if everything ok run this command: 

ansible all -m ping -s -k -u vagrant

Result should be:
machine2 | SUCCESS => {
    "changed": false,
    "ping": "pong"

}

First Playbook is to install java and tomcat in second machine.

playbook-tomcat.yml :

 - hosts: machine2  
  vars:  
   http_port: 80  
   max_clients: 200  
  remote_user: vagrant  
  tasks:  
   - name: updates a server  
    apt: update_cache=yes  
   - name: upgrade a server  
    apt: upgrade=full  
   - name: install java   
    apt: name=default-jdk state=latest  
   - name: install tomcat  
    apt: name=tomcat7 state=latest  
   - name: make sure apache is running  
    service: name=tomcat7 state=started  

ansible-playbook playbook-tomcat.yml -sudo -u vagrant --ask-pass


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