Immutable Deployment

Immutable infrastructure and continuous deployment

Introduction

• Mutable Server Infrastructure

• Immutable Server Infrastructure

Practical Differences: Embracing the Cloud

Conceptual Differences: Pets vs Cattle

Benefits

• Known-good server state and fewer deployment failures
• No configuration drift or snowflake servers
• Consistent staging environments
• Easy horizontal scaling
• Simple rollback and recovery processes

Recommendation and Requirements

• Servers in a cloud computing environment
• Full automation of your entire deployment pipeline
• Service-oriented architecture
• Stateless, volatile application layer
• Persistent data layer

Process overview

Artifact deployment script

Make changes to code

Create ELB

Create Route53

Build artifact

Bake AMI

Create LC

Create OR Update ASG

One Time Setup

Deploy new version

Deployment Flow

Env

Rolling Blue/Green

Ansible Immutable Deployment script

- name: provision new instance

hosts: localhost

vars_files:

- extra_vars/{{ env }}_all.yml

- extra_vars/{{ evn }}_backend/build.yml

roles:

- role: launch_instance

​

- name: deploy artifact

hosts: {{ env }}_backend_build

remote_user: admin

become_method: sudo

become: yes

become_user: root

roles:

- deploy-backend

- name: deploy new release

hosts: localhost

vars:

release: "{{ backend_release }}"

vars_files:

- extra_vars/{{ env }}_all.yml

- extra_vars/{{ env }}_backend/build.yml

roles:

- create-ami

- create-launch-configuration

- update-autoscaling

​

- clean up

hosts: localhost

vars_files:

- extra_vars/{{ env }}_all.yml

roles:

- terminate_instance

- delete-old-ami