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Leveraging Ansible to automate AWS instance management
Ansible is an open-source software automation tool suited for instance configuration and provisioning, enabling an Infrastructure as Code approach to the Cloud.
In this page we provide a set of ansible-playbooks templates to perform the most common task to tune EC2 instance types with Akamas, such as:
- EC2 instance creation
- EC2 instance termination
- EC2 instance resizing
Refer to the Ansible documentation and to the Ansible ec2 module for more details, and make sure to check the concepts behind inventory management to build a robust automation.
The orchestrator requires access to an account or role linked to the correct policies; this requires managing AWS Policies and having access to the required security groups.
The following example playbook provisions an EC2 instance using the latest Ubuntu 18-04 LTS image and then waits for it to be available.
The playbook requires the following set of arguments:
- key: the name of the SSH key pair to use
- Name: the instance name
- security_group: the name of the AWS security group
- region: the selected AWS region
You can update the
ec2_ami_info task to query for a different AMI family or specify directly the id under ec2.image.- intance_type: type of instance to provision
- volume_size: size of the attached volume
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# Launch an ubuntu instance and wait for ssh
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- name: Create an instance request
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hosts: localhost
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gather_facts: False
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tasks:
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- name: query api
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ec2_ami_info:
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filters:
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name: "ubuntu/images/hvm-ssd/ubuntu-bionic-18.04-amd64-server-*"
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owner-id: "099720109477" # Canonical Group Limited
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register: amis
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- name: sort by creation date
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set_fact:
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sorted_amis: "{{ amis.images | sort(attribute='creation_date') }}"
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- name: get latest
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set_fact:
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latest_ami: "{{ sorted_amis | last }}"
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- name: Launch instance
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ec2:
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key_name: "{{ key }}"
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instance_type: "{{ instance_type | default('m5.xlarge') }}"
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group:
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- <your-security-groups>
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image: "{{ latest_ami.image_id }}"
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count: "{{ count | default('1') }}"
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wait: yes
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wait_timeout: 500
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region: "{{ region }}"
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spot_wait_timeout: 600
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instance_initiated_shutdown_behavior: terminate
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ebs_optimized: yes
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volumes:
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- device_name: /dev/sda1
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volume_type: gp2
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volume_size: "{{ volume_size | default('20') }}"
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delete_on_termination: yes
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instance_tags:
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Name: "{{ Name }}"
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CNAME: "{{ Name }}.<your-domain>"
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register: ec2
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- name: Wait for SSH to come up
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wait_for:
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host: "{{ item.public_dns_name }}"
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port: 22
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delay: 60
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timeout: 320
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state: started
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with_items: "{{ ec2.instances }}"
To apply the EC2 parameters from the AWS Optimization Pack selected by the Akamas engine you can generate the playbook arguments through a template like the following one, where
ec2 is the name of the component:ansible-playbook -i inventory --extra-vars "instance_type=${ec2.aws_ec2_instance_type}.${ec2.aws_ec2_instance_size}" provision.yaml
The following playbook terminates all instances with the specified name (or any other tag).
It requires the following arguments:
- instance_name: the name instances name
- region: the selected AWS region
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# Terminate an aws instance
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- name: Terminate instance
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hosts: localhost
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gather_facts: False
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tasks:
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- name: retrieve instance info
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ec2_instance_info:
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filters:
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"tag:Name": "{{ instance_name }}"
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register: ec2
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- name: terminate the instance
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ec2:
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state: absent
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instance_ids:
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- "{{ item.instance_id }}"
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region: "{{ region }}"
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with_items: "{{ ec2.instances }}"
Instance resizing is a little trickier to deploy as it requires you to install AWS CLI and setup the required credentials.
The following playbook provides a simple way to stop, update and restart your instance: it is intended as a building block for more elaborate workflows.
It makes use of a list of arguments:
- instance_name: your instance name
- region: the selected AWS region
For a successful workflow it requires:
- The instance to exist
- The instance to be unique
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# Change instance type, requires AWS CLI
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- name: Resize the instance
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hosts: localhost
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gather_facts: no
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connection: local
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tasks:
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- name: save instance info
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ec2_instance_info:
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filters:
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"tag:Name": "{{ instance_name }}"
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register: ec2
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- name: stop the instance
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ec2:
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region: "{{ region | default('us-east-2') }}"
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state: stopped
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instance_ids:
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- "{{ ec2.instances[0].instance_id }}"
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instance_type: "{{ ec2.instances[0].instance_type }}"
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wait: True
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- name: Change the instances ec2 type
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shell: >
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aws ec2 modify-instance-attribute --instance-id "{{ ec2.instances[0].instance_id }}"
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--instance-type "{{ new_instance_type }}"
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delegate_to: localhost
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- name: restart the instance
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ec2:
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region: "{{ region }}"
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state: running
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instance_ids:
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- "{{ ec2.instances[0].instance_id }}"
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wait: True
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register: ec2
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- name: wait for SSH to come up
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wait_for:
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host: "{{ item.public_dns_name }}"
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port: 22
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delay: 60
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timeout: 500
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state: started
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with_items: "{{ ec2.instances }}"
To apply the EC2 parameters from the AWS Optimization Pack selected by the Akamas engine you can generate the playbook arguments through a template like the following, where
ec2 is the name of the component:ansible-playbook -i inventory --extra-vars "new_instance_type=${ec2.aws_ec2_instance_type}.${ec2.aws_ec2_instance_size}" resize.yaml