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readme.md

Ansible

IAAC - provision servers and configure servers with right software.

Create Template -> Provision Server -> Install Software -> Configure Software -> Deploy App

Ansible is IAAC tool used for configuration management (install and configure software).

Install ansible

https://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html

pip install ansible
ansible --version

Create EC2 instance for ansible

https://us-east-1.console.aws.amazon.com/ec2

Ansible talks to servers via ssh keys to manage software.

Go to AWS and create EC2 instance.

check 09-multiple-ec2-instances folder.

export AWS_SECRET_ACCESS_KEY=XXXX 
export AWS_ACCESS_KEY_ID=XXXX
terraform init
terraform apply
...

http_server_public_dns = [
  "ec2-54-158-89-105.compute-1.amazonaws.com",
  "ec2-18-234-187-237.compute-1.amazonaws.com",
]

Setup Ansible project

Any change with ansible is something called play and all of them are stored in playbook

All ansible scripts are stored in playbook folder.

Ansible configuration stored in ansible.cfg.

Ansible EC2 AWS instance config (ip, etc.) stored in ansible_hosts file.

ansible --version 
config file = /Users/fox/files/myprojects/devops-master-class/ansible/ansible.cfg

# able to ping all servers
chmod 400 ~/aws/aws_keys/default-ec2.cer
ansible -m ping all
...
3.93.240.150 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}

Ansible commands

# run command on all servers
ansible all -a 'whoami'
# ssh to ec2 host
ssh -vvv -i ~/aws/aws_keys/default-ec2.cer ec2-user@3.80.29.192

Ansible host file and host groups

# add host name to ansible_hosts

dev1 ansible_host=3.80.29.192
dev2 ansible_host=3.93.240.150
qa1 ansible_host=18.208.145.16

# on all devices
ansible all -a 'python --version'
# on dev devices only
ansible dev -a 'python --version'
# run on a group 
ansible first -a 'python --version'
ansible groupofgroups -a 'python --version'
ansible devsubset -a 'python --version'
ansible --list-host all
ansible --list-host \!first

Add ping playbook

# first play
- hosts: all
  tasks:
    # first task
    - name: Ping All Servers
      action: ping
    # second task
    - debug: msg="First"
# second play
# run only on dev hosts
- hosts: dev
  tasks:
    - debug: msg="First"
# run playbook
ansible-playbook playbooks/01-ping.yaml

This is a play that can have multiple tasks.

Understand control node, managed nodes and Inven

Scripts -> Ansible -> Server1/2/3

  • Control node - machine where ansible is running, where you control all hosts.
  • Other servers are management nodes.
  • Inven what we have in ansible_host file.
# first play
- hosts: qa
  tasks:
    # first task
    - name: Execute shell commands
      shell: uname
      register: uname_result
    # second task
    # {{ var }}
    - debug: msg="{{ uname_result }}"
ansible-playbook playbooks/02-shell.yaml
PLAY [qa] ********************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************

TASK [Execute shell commands] ************************************************************************************
changed: [qa1]

TASK [debug] *****************************************************************************************************
    "msg": {
        "changed": true,
        "cmd": "uname",
        "delta": "0:00:00.038775",
        "end": "2022-04-10 18:49:09.096328",
        "failed": false,
        "msg": "",
        "rc": 0,
        "start": "2022-04-10 18:49:09.057553",
        "stderr": "",
        "stderr_lines": [],
        "stdout": "Linux",
        "stdout_lines": [
            "Linux"
        ]
    }
}

PLAY RECAP *******************************************************************************************************
qa1                        : ok=3    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Ansible variables

Variables are read via {{ var }} syntax.

# first play
- hosts: dev
  vars_files:
    - variables.yaml
  tasks:
    # first task
    - name: Var Value
      debug: msg="Value is {{ var1 }}"

Use from var command line

ansible-playbook playbooks/03-vars.yaml -e var1=CMDVal

Read vars from file

# variables.yaml

var1: "Yaml Value"

Ansible Facts

Facts are general info about ansible controller and managed hosts collected in setup.

- hosts: qa
  tasks:
    - name: Kernel
      debug: msg="{{ ansible_kernel }}"
    - name: Hostname
      debug: msg="{{ ansible_hostname }}"
    - name: Distrib
      debug: msg="{{ ansible_distribution }}"
    - debug: var=ansible_architecture
ansible-playbook playbooks/04-facts.yaml

PLAY [qa] ********************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************
ok: [qa1]

TASK [Kernel] ****************************************************************************************************
    "msg": "5.10.102-99.473.amzn2.x86_64"
}

TASK [Kernel] ****************************************************************************************************
ok: [qa1] => {
    "msg": "ip-172-31-84-123"
}

TASK [Kernel] ****************************************************************************************************
ok: [qa1] => {
    "msg": "Amazon"
}
ok: [qa1] => {
    "ansible_architecture": "x86_64"
}

PLAY RECAP *******************************************************************************************************
qa1                        : ok=4    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0  
# list of servers ansible managing right now
# you can get vars from there like 'ansible_kernel' and 'ansible_hostname'
ansible qa -m setup

Install http server on hosts

Install Apache on all dev servers.

- hosts: dev
  become: true
  tasks:
    - yum:
        # install httpd on ec2 instances
        name:
          - httpd
        state: present
    # we are starting httpd server
    - service: name=httpd state=started enabled=yes
    # copy msg to index.html file
    - raw: 'echo Welcome | sudo tee /var/www/html/index.html'
ansible-playbook playbooks/05-install-apache.yaml

Check http://3.80.29.192 via web, http server should run.

Reuse ansible playbooks

- import_playbook: 01-ping.yaml
- import_playbook: 02-shell.yaml
- import_playbook: 03-vars.yaml
# check all tasks
ansible-playbook playbooks/06-playbooks.yaml --list-tasks
# run only on qa env 
ansible-playbook -l qa playbooks/01-ping.yaml

Conditional and loops

- hosts: qa
  vars:
    system: "Cisco"
    color: "Red"
  tasks:
    - debug: var=ansible_system
    - debug: var=color
      # run when system is Linux
      when: system == 'Linux'
    # execute loop with multiple items, each item with name and country
    - debug: var=item
      with_items:
      - name: Sam
        country: US
      - name: Luke
        country: GB
ansible-playbook playbooks/07-conditionals-loops.yaml

ok: [qa1] => (item={'name': 'Sam', 'country': 'US'}) => {
    "ansible_loop_var": "item",
    "item": {
        "country": "US",
        "name": "Sam"
    },
    "item.name": "Sam"
}
ok: [qa1] => (item={'name': 'Luke', 'country': 'GB'}) => {
    "ansible_loop_var": "item",
    "item": {
        "country": "GB",
        "name": "Luke"
    },
    "item.name": "Luke"
}

EC2 dynamic inventory

Multiple EC2 servers we created via terraform.

pip install boto3

Create 01-aws_ec2.yaml dynamic inventory file.

plugin: aws_ec2
region:
  - us-east-1
# add groups
keyed_groups:
  - prefix: arch # will group based on architecture
    key: 'architecture'
  - prefix: tag
    key: 'tags' # will group based on tag
  - key: tags.Env
    separator: ''
  - key: instance_type
    prefix: instance_type
# list of servers info
ansible-inventory --list
# group instances
ansible-inventory --graph
ansible-playbook playbooks/08-dynamic.yaml

Create EC2 with ansible

https://us-east-1.console.aws.amazon.com/ec2

You can use ansible for provision servers.

- hosts: localhost
  tasks:
    # create ec2 instances
    - ec2:
        # taken from Key Pairs
        key_name: default-ec2
        instance_type: t2.micro
        # AMI - simple template for all the software.
        image: ami-0c02fb55956c7d316
        region: us-east-1
        # how many instances
        count: 1
        # took from launch instance -> Configure Instance -> subnet id
        vpc_subnet_id: subnet-03e9bbe7f48e853a7
        assign_public_ip: yes
        # security group
        group: ["http_server_sg"]
        instance_tags: {type: http, Environment: QA}
        wait: yes
      register: ec2_output
    - debug: var=ec2_output
ansible-playbook playbooks/09-create-ec2.yaml

Declarative configuration for ansible

...
  exact_count: 2
  count_tag: {type: http}  # create instances wih tag 'http'
...

Delete EC2 instances

cd 09-multiple-ec2-instances
terraform destroy