Ansible - AWS : creating an ELB & registers an EC2 instance from the ELB

Ansible 2.0

Ansible is a configuration management tool, and unlike Chef and Puppet, it uses a push mechanism to push the desired changes on the servers using ssh-agent.

In this article, we'll create an EC2 instance, ELB and attach the instance to ELB.

Requirements (on host that executes module):

1. python >= 2.6
2. boto - Ansible's EC2 module uses python-boto library to call AWS API, and boto needs AWS credentials in order to function. So we need the boto installed on our local host. Though there are many ways to set our AWS credentials, in this tutorial, we'll create a file under our user home folder (~/.boto):

   [Credentials]
   AWS_ACCESS_KEY_ID=KID...CWU
   AWS_SECRET_ACCESS_EY=3qv...DSP
   

Here is our playbook (site.yml) to create an instance:

---
- name: A simple Load Balanced AWS server
  hosts: localhost 
  connection: local
  gather_facts: False
  tasks:
    - name: Create security group
      ec2_group:
        name: "demo_security_group"
        description: "demo security group"
        region: "{{ region }}"
        rules:
          - proto: tcp  # ssh
            from_port: 22
            to_port: 22
            cidr_ip: 0.0.0.0/0
          - proto: tcp  # http
            from_port: 80
            to_port: 80
            cidr_ip: 0.0.0.0/0
          - proto: tcp  # https
            from_port: 443
            to_port: 443
            cidr_ip: 0.0.0.0/0
        rules_egress:
          - proto: all
            cidr_ip: 0.0.0.0/0
      register: demo_firewall

    - name: Create an EC2 instance
      ec2:
        key_name: "{{ pem_key }}"
        region: "{{ region }}"
        group_id: "{{ demo_firewall.group_id }}"
        instance_type: "{{ instance_type }}"
        image: "{{ ami }}"
        wait: yes
        instance_tags:
            env: "{{ env }}"
        count_tag: env
        exact_count: 1
        vpc_subnet_id: subnet-66d25311
        assign_public_ip: yes
      register: ec2

    - name: wait for the servers to appear on the network
      wait_for: host={{ item.public_dns_name }} port=22 delay=10 timeout=180 state=started
      with_items: ec2.tagged_instances

    - name: add server ip addresses to hosts group
      add_host: hostname={{ item.public_ip }} groupname=launched
      with_items: ec2.tagged_instances

- name: webservers (installs nginx ...)
  hosts: launched
  remote_user: ubuntu
  become: true
  become_method: sudo
  gather_facts: True
  roles:
    - web

- name: spin up the load balancer and add the servers to it
  hosts: 127.0.0.1
  connection: local
  gather_facts: False
  tasks:
    - name: setup a simple load balancer
      ec2_elb_lb:
        name: aws-elb-demo
        state: present
        region: us-east-1
        zones:
          - us-east-1a
        listeners:
          - protocol: http
            load_balancer_port: 80
            instance_port: 80
      register: aws-elb-demo

    - name: add the webservers to the load balancer
      local_action: ec2_elb
      args:
        instance_id: "{{ item.id }}"
        ec2_elbs: aws-elb-demo
        state: present
        region: us-east-1
      with_items: ec2.tagged_instances

Let's run the playbook:

$ ansible-playbook site.yml  --private-key /home/k/.ssh/einsteinish.pem
 [WARNING]: provided hosts list is empty, only localhost is available

PLAY [A simple Load Balanced AWS server] ***************************************

TASK [Create security group] ***************************************************
ok: [localhost]

TASK [Create an EC2 instance] **************************************************
ok: [localhost]

TASK [wait for the servers to appear on the network] ***************************
ok: [localhost] => (item={u'kernel': None, u'root_device_type': u'ebs', u'private_dns_name': u'ip-172-31-44-178.ec2.internal', u'public_ip': u'52.90.145.182', u'private_ip': u'172.31.44.178', u'id': u'i-0503d03ac7b282a0c', u'ebs_optimized': False, u'state': u'running', u'virtualization_type': u'hvm', u'architecture': u'x86_64', u'ramdisk': None, u'block_device_mapping': {u'/dev/sda1': {u'status': u'attached', u'delete_on_termination': True, u'volume_id': u'vol-0ee7cb23a0ba4c219'}}, u'key_name': u'einsteinish', u'image_id': u'ami-49c9295f', u'tenancy': u'default', u'groups': {u'sg-480a6d37': u'demo_security_group'}, u'public_dns_name': u'ec2-52-90-145-182.compute-1.amazonaws.com', u'state_code': 16, u'tags': {u'env': u'demo'}, u'placement': u'us-east-1c', u'ami_launch_index': u'0', u'dns_name': u'ec2-52-90-145-182.compute-1.amazonaws.com', u'region': u'us-east-1', u'launch_time': u'2017-04-03T04:29:09.000Z', u'instance_type': u't2.nano', u'root_device_name': u'/dev/sda1', u'hypervisor': u'xen'})

TASK [add server ip addresses to hosts group] **********************************
changed: [localhost] => (item={u'kernel': None, u'root_device_type': u'ebs', u'private_dns_name': u'ip-172-31-44-178.ec2.internal', u'public_ip': u'52.90.145.182', u'private_ip': u'172.31.44.178', u'id': u'i-0503d03ac7b282a0c', u'ebs_optimized': False, u'state': u'running', u'virtualization_type': u'hvm', u'architecture': u'x86_64', u'ramdisk': None, u'block_device_mapping': {u'/dev/sda1': {u'status': u'attached', u'delete_on_termination': True, u'volume_id': u'vol-0ee7cb23a0ba4c219'}}, u'key_name': u'einsteinish', u'image_id': u'ami-49c9295f', u'tenancy': u'default', u'groups': {u'sg-480a6d37': u'demo_security_group'}, u'public_dns_name': u'ec2-52-90-145-182.compute-1.amazonaws.com', u'state_code': 16, u'tags': {u'env': u'demo'}, u'placement': u'us-east-1c', u'ami_launch_index': u'0', u'dns_name': u'ec2-52-90-145-182.compute-1.amazonaws.com', u'region': u'us-east-1', u'launch_time': u'2017-04-03T04:29:09.000Z', u'instance_type': u't2.nano', u'root_device_name': u'/dev/sda1', u'hypervisor': u'xen'})

PLAY [webservers (installs nginx ...)] *****************************************

TASK [setup] *******************************************************************
ok: [52.90.145.182]

TASK [web : Installs nginx web server] *****************************************
changed: [52.90.145.182]

TASK [web : Upload default index.html for host] ********************************
changed: [52.90.145.182]

RUNNING HANDLER [web : start nginx] ********************************************
ok: [52.90.145.182]

PLAY [spin up the load balancer and add the servers to it] *********************

TASK [setup a simple load balancer] ********************************************
ok: [localhost]

TASK [add the webservers to the load balancer] *********************************
changed: [localhost -> localhost] => (item={u'kernel': None, u'root_device_type': u'ebs', u'private_dns_name': u'ip-172-31-44-178.ec2.internal', u'public_ip': u'52.90.145.182', u'private_ip': u'172.31.44.178', u'id': u'i-0503d03ac7b282a0c', u'ebs_optimized': False, u'state': u'running', u'virtualization_type': u'hvm', u'architecture': u'x86_64', u'ramdisk': None, u'block_device_mapping': {u'/dev/sda1': {u'status': u'attached', u'delete_on_termination': True, u'volume_id': u'vol-0ee7cb23a0ba4c219'}}, u'key_name': u'einsteinish', u'image_id': u'ami-49c9295f', u'tenancy': u'default', u'groups': {u'sg-480a6d37': u'demo_security_group'}, u'public_dns_name': u'ec2-52-90-145-182.compute-1.amazonaws.com', u'state_code': 16, u'tags': {u'env': u'demo'}, u'placement': u'us-east-1c', u'ami_launch_index': u'0', u'dns_name': u'ec2-52-90-145-182.compute-1.amazonaws.com', u'region': u'us-east-1', u'launch_time': u'2017-04-03T04:29:09.000Z', u'instance_type': u't2.nano', u'root_device_name': u'/dev/sda1', u'hypervisor': u'xen'})

PLAY RECAP *********************************************************************
52.90.145.182              : ok=4    changed=2    unreachable=0    failed=0   
localhost                  : ok=6    changed=2    unreachable=0    failed=0   

where the "einsteinish.pem" is my private key.

Since we installed nginx, we should see a default page

Github source available here.

Here are other files.

web/tasks/main.yml:

- name: Installs nginx web server
  apt: pkg=nginx state=installed update_cache=true
  notify:
    - start nginx

- name: Upload default index.html for host
  copy: src=static_files/index.html dest=/usr/share/nginx/www/ mode=0644

web/handlers/main.yml:

- name: start nginx
  service: name=nginx state=started

web/static_files/main.yml:

<html>
  <head>
    <title>This is a sample page</title>
  </head>
  <body>
    <h1>Here is a heading!</h1>
    <p>Here is a regular paragraph.  Wow!</p>
  </body>
</html>

group_vars/all:

region: us-east-1
instance_type: t2.nano
ami: ami-49c9295f  # Ubuntu 14.04 LTS
app_code_user: "ubuntu" # remote user
env: demo
pem_key: einsteinish # key.pem

Ansible 2.0