Dynamic Inventory with Ansible
How to setup dynamic inventory with Ansible
Using dynamic inventory for Ansible
Video Tutorial
Initial Setup
Prerequisites:
- Install and setup Ansible
- Install boto (version>=2.24.0)
Make sure the ec2.py you are using should have –profile option . Use the latest ec2.py and boto with version>=2.24.0
Make the script executable by command chmod +x ec2.py
Configure the file ec2.ini file to work for particular region as shown below. this would decrease the execution time as the search for the resource would get limited to a particular region.
regions = us-east-1
Change ansible configuration file, ansible.cfg, to point to ec2.py as a host file
[defaults]
remote_user = root
host_key_checking = False
inventory = ./inventory/ec2.py
Now test the setup by running ./ec2.py –list. This should give the list of resources in the region we have se specified. If you get an error like below
region name: ap-south-1 likely not supported, or AWS is down.
Add the ap-south-1 region in the regions_exclude in ec2.ini file.
regions_exclude = us-gov-west-1,cn-north-1,ap-south-1
This will remove the error and will list the resources as expected.
Writing Playbook
First, define some default variable in a file all.yml in group_vars directory
mkdir group_vars
vi group_vars.all.yml
Add the following variables
---
# group_vars/all.yml
image: ami-7243e611
subnet: subnet-417fff25
region: ap-southeast-1
zone: ap-southeast-1a # zone that the master AMI will be configured in
keypair: mykey
security_groups: sample_subnet
instance_type: t2.micro
volumes:
- device_name: /dev/xvda
device_type: gp2
volume_size: 8 # size of the root disk
delete_on_termination: true
Let’s create a role to launch an ec2 instance
mkdir -p roles/launch/tasks
vi roles/launch/tasks/main.yml
# roles/launch/tasks/main.yml
- name: Launch new instance
ec2:
region: "{{ region }}"
vpc_subnet_id: "{{ subnet }}"
keypair: "{{ keypair }}"
zone: "{{ zone }}"
group: "{{ security_groups }}"
image: "{{ image }}"
instance_type: "{{ instance_type }}"
instance_tags:
Name: "{{ name }}"
volumes: "{{ volumes }}"
wait: yes
assign_public_ip: yes
register: ec2
- name: Add new instances to host group
add_host:
name: "{{ item.public_dns_name }}"
groups: "{{ name }}"
ec2_id: "{{ item.id }}"
with_items: "{{ ec2.instances }}"
- name: Wait for instance to boot
wait_for:
host: "{{ item.public_dns_name }}"
port: 22
delay: 30
timeout: 300
state: started
with_items: "{{ ec2.instances }}"
vi launch_instance.yml
---
# launch_instance.yml
- hosts: localhost
connection: local
gather_facts: no
roles:
- role: launch
name: "{{ group_name }}-role-name"
Now simply run the playbook launch_instance.yml with the following command.
AWS_PROFILE=personal ansible-playbook -i hosts -e group_name=example launch_instance.yml -vvvv
This will launch the instance and you can also verify if the resources in the list of dynamic inventory got updated or not by running the following command
./ec2.py --list --profile personal --refresh-cache
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